PDA

View Full Version : Wiring, conduit or no conduit



tiptop
12-31-2008, 11:53 AM
Hello All, my shop expansion project is moving right along. I called my insurance agent and found out that it would be cheaper to drop it from my homeowners policy and insure it as a separate structure. He then told me that if my wiring was in conduit it would be considerably cheaper yet and if I added a liability clause I could do commercial work. This is the direction I plan on taking it eventually. Fortunately I do not have many circuits in the old shop so changing over will not be to bad.
My question is, which conduit is the preferred style for a commercial structure, PVC or steel? My preference would be PVC as it is a lot easier to work with.

Jay

Carld
12-31-2008, 12:31 PM
Gray PVC is best as you can bend it with heat to make special bends. It's easy to work with and is legal to use. I love the stuff and my shop is totaly wired with it.

if you heat it to bend it get a heat gun, don't use a torch.

alanganes
12-31-2008, 12:49 PM
I have my garage shop wired with the grey PVC stuff. It is just to easy to work with it seemed almost a no-brainer for me, even though I have benders and such for doing EMT.

So long as the it will meet the requirements of the insurance co. to give you the discount, I'd second the PVC .

Luke55
12-31-2008, 12:50 PM
Pvc is the best choice in humid or dry environment. When conduits are subject to be hit by machinery or meterial, metal conduits are required. liquitight or TEC wire can be used too. Always depend on your local electrical code and insurance requirements.

Doozer
12-31-2008, 12:55 PM
Metal conduit is required for commercial insurance.
The wires can start on fire inside metal conduit, and not burn the place down.
Not so with PVC conduit.
--Doozer

GKman
12-31-2008, 01:07 PM
I hated working with thinwall conduit until I found offset connectors. They have the correct offset so that boxes and conduit both fit tight against the wall without bending an offset in the conduit. Makes a nice looking job easily.

I've seen enough mental illness that your byline makes me want to puke.

Al Flipo
12-31-2008, 03:28 PM
You should go with steel and not plastic, rent a bender end you will end up with a nice looking job.

alanganes
12-31-2008, 03:52 PM
I've seen enough mental illness that your byline makes me want to puke.

I too have dealt with enough MENTAL illness amongst people I know to agree with that sentiment, but you may want to carefully re-read the OP's tag line...

:)

aboard_epsilon
12-31-2008, 04:06 PM
Don't know about your plastic conduit ..

but ours is square with snap on lids ..

and all different sizes ..

so in my workshop i have a massive one holding some twenty twin and earths that serves as the main loom.. off it I branch smaller conduits.

at any time i can add more runs without having to thread them down pipes or change the main loom conduit .

all the best.markj

kf2qd
12-31-2008, 04:10 PM
I would say go with thin wall metal conduit. The bender is inexpensive and you never know what other uses you will come up with for it. The first few bends take a little thought but after that you can bend just about any shape you might need. 1/2 & 3/4 thin wall and rigid are both easy to bend by hand so there is not much expense there for the bender. Just make sure to ream the inside of the tube at any cut - and don't use a pipe cutter, use a hacksaw - those burrs from a pipe cutter will take forever to remove - and if you don't get it removed can shred insulation.

Bob Ford
12-31-2008, 04:13 PM
Use metal conduit. Do you need help? I am Retired Electrician.

Bob

barts
12-31-2008, 05:11 PM
My question is, which conduit is the preferred style for a commercial structure, PVC or steel? My preference would be PVC as it is a lot easier to work with.


Go with EMT; it's easy to install, resists all but the most egregious misuse and helps prevent rather than accelerate fires.

When I build my shop for retirement, it will be entirely wired w/ EMT on the surface of the "finish" walls & ceiling, including subpanels, etc.

New machinery arrives, tools accumulate - it's good to be able to add outlets or dedicated power drops where you need them w/o a lot of fuss.

- Bart

Peter.
12-31-2008, 05:25 PM
Don't know about your plastic conduit ..

but ours is square with snap on lids ..

and all different sizes ..

so in my workshop i have a massive one holding some twenty twin and earths that serves as the main loom.. off it I branch smaller conduits.

at any time i can add more runs without having to thread them down pipes or change the main loom conduit .

all the best.markj

I use that also - it makes for easy additions to the wiring. I only have two circuits though one power ring and one lighting. Plastic round conduit is very prevalent over there though.

dp
12-31-2008, 05:27 PM
I used 1/2" metal conduit here. It took about 2 tries to get the bending right and it went quickly from there. In perfect hindsight I wish now I'd have wired the place with larger conduit and heavier wire. 14g doesn't cut it when the table saw spools up.

K Barton
12-31-2008, 05:55 PM
Hello Jay: Have been following your posts on your shop addition, I have finally made the jump to register on the "BBS" and this is my first post. I would go with EMT 3/4" trade size as a minimumn haveing seen you set up during the scrapeing class that Forest taught this summer, it looks like your shop is comming along well, & that you have aquired more metal since then.

Ken

Steve Stube
12-31-2008, 06:05 PM
In perfect hindsight I wish now I'd have wired the place with larger conduit and heavier wire. 14g doesn't cut it when the table saw spools up.

Oh but Dennis folks brag about how easy it is to change things around with exposed conduit - so you really don't have a problem, right? ;)

One regret I have about my shop build is using any #14 romex wire. Although my #14 is only in lighting circuits I under estimated lighting requirements for my older eyes. Hindsight, no #14 ever again.

lazlo
12-31-2008, 07:15 PM
In perfect hindsight I wish now I'd have wired the place with larger conduit and heavier wire. 14g doesn't cut it when the table saw spools up.

I'm not an electrician, but you really need to match the wiring ampacity with the circuit it's feeding. The NEC rates 14AWG copper as 15A max.

I've done all my own wiring in the shop, and running 6 gage wire for a 60A circuit is a PITA, but I sleep better at night knowing I'm not going to have an electrical fire :)

http://www.okonite.com/engineering/nec-ampacity-tables.html

jdunmyer
12-31-2008, 07:26 PM
Go with EMT. When you buy the benders, they come with instructions that are really pretty adaquet.

Besides the benders, get an electrician's deburring tool to use after cutting the conduit with a fine-tooth hacksaw. If you can borrow or rent a Greenlee offset bender, it'll speed things up a bit, but I've done a fair amount of EMT work and only got one recently. They run about $150.00 or more new, about half that on eBay. You probably only really need the 1/2" size. You should also have an automatic wire stripper.

Do get a book to tell you about grounding, using those little pigtail wires. Use only stranded wire, of course.

Bendng conduit is easy, and you'll waste surprisingly little of it while learning.

Here's how we wired my wife's woodshop: http://www.oldengine.org/members/jdunmyer/woodshop/index.htm

rockrat
12-31-2008, 08:21 PM
Metal and ground, ground, ground. My insurance guy told me he doesn't want to see the place if there is PVC conduit for the 3 phase.

Besides, if I'm welding and there is conduit somewhere that a hot little bugger can get to, then it better be metal. I wonder, after seeing all the glowing chips flying off a mill, if there has been a "thermal event" related to PVC. I would imagine that there has been.

rock~

dp
12-31-2008, 08:47 PM
I'm not an electrician, but you really need to match the wiring ampacity with the circuit it's feeding. The NEC rates 14AWG copper as 15A max.

That's the value of hindsight. When I wired it I was not thinking of any machines being in there - that just happened over time :)

Back then I had only bench tools like belt sanders, routers, etc. All the machinery started showing up when my wife dragged home an old Craftsman wood lathe that had never been used. Things just kinda spiraled out of that. Sound familiar?

wierdscience
12-31-2008, 09:10 PM
Another vote for EMT.A hicky bender and a box of fittings and get to it.It pays to run bigger conduit now than add another run later for one more run of wire.3/4 is the smallest I consider,1" a good trade between cost and future flexibility.

lugnut
12-31-2008, 09:31 PM
Jay I think you should take a good look at the Newport/Oregon electrical code. I know they use a lot of the plastic conduit. It sure would be a lot simpler to run. I have benders for the metal conduit (that you can have) if you go that route.
Mel

J Tiers
12-31-2008, 10:57 PM
Another vote for EMT.....

It is tougher, probably a little safer, critters can't chew it, etc.

The PVC however, is flame retardant, so that shouldn't be a big issue. And with it, you HAVE to run ground wires, none of this "use the raceway" nonsense.

If you just don't want to do either, you may be able to use type MC, it is armored cable with a grounding conductor. I like it because it is easy to install, and is also vermin-proof.... there have been a few fires started by mice etc chewing the NM cables. I don't want to join the list. You can get 12 ga MC.

Lu47Dan
01-01-2009, 12:06 AM
Another vote for EMT , I have worked on a lot of construction sites and see very little PVC conduit . Mostly used as underground conduit . Benders , reamer , fish tape , and a roll of pulling tape won't set you back too much money . Buy unistrut and the correct clamps for securing your runs and it will make the job look more professional also .
I regret burying all the wiring in the walls of my shop years ago , I can not mount anything on the walls of the shop without worrying about hitting a hidden wire today . You forget over time which side of the stud did you ran the wire on . With the remodel of the front part to my shop into a machine room I have decided to go with EMT for all circuits , nothing smaller than 12ga wire .
Dan

clutch
01-01-2009, 02:16 AM
I'm going to vote for EMT also. It isn't that hard to run if you read the instructions that come with your bender. I'd use 3/4" to leave capacity to expand for that circuit you later need.

There are rules on how many current carrying conductors, wire size, % of fill and such. You just can't cram it full.

I get out the NEC book and look it up or call my brother the master electrician if I am being lazy. :D

Insulate, put up drywall, and have your conduit on the show side. It is a shop, no need to hide wires in walls.

Clutch

doctor demo
01-01-2009, 04:55 AM
Don't know about your plastic conduit ..

but ours is square with snap on lids ..

and all different sizes ..

so in my workshop i have a massive one holding some twenty twin and earths that serves as the main loom.. off it I branch smaller conduits.

at any time i can add more runs without having to thread them down pipes or change the main loom conduit .

all the best.markj
Mark, I would agree with You on the ''raceway '' with snap lids. I used 4'' X4'' in 10' lengths and run 1/2 and 3/4 inch emt off of it to My individual circuts. Now when I want to change or add something all I have to do is pop off the lid and do what ever work needed and pop the lid back on.

Steve

Your Old Dog
01-01-2009, 06:41 AM
My question is, which conduit is the preferred style for a commercial structure, PVC or steel? My preference would be PVC as it is a lot easier to work with.

Jay

I disagree, I used steel and it was much simpler to work with. I bought a Home Depot bender, made my bends first and cut off the excess after the bends were made to avoid all the math. It worked great and looks neat. As I'm a one man shop operating only one piece of equipment at a time I put in wall plugs all over the place. Gee it's great not having to unplug something to plug something else in! I'd go with steel. I went 1/2 inch but should have went 3/4 as others have said. This is a workshop only so all my wiring is at eyelevel and easy to install. Very few of my cords touch the floor so it make cleanup a snap.


..............I've done all my own wiring in the shop, and running 6 gage wire for a 60A circuit is a PITA, but I sleep better at night knowing I'm not going to have an electrical fire :)


In the same vain as lazlo's remark, that's why I don't want anything on my floor except table legs. I always worry that a spark will get some place and fester while I'm sleeping. Must be fear developed from being a tv newsphotographer. I have seen the "other" people this stuff happens to and they look exactly like us.

John Stevenson
01-01-2009, 07:30 AM
3" x 3" steel box section here with 1/4 turn screwed lids all round every shop at roof level. 3/4" steel conduit drop downs with all screwed fittings, mostly all straight runs into isolator boxes mounted behind the machine or into metal clad dual sockets.

http://www.stevenson-engineers.co.uk/files/sockets2.jpg

Not a particularly good shot just one out of a folder I have but you can see the top box runs going round 2 walls and the two boxes behind the Bridgy

No bender used or needed, just a die stock with 3/4" conduit die, and a step drill for drilling the box section.

If there are any conduit runs with bends in that is because they already had them in as all my gear was scrounged off industrial demolition sites. I just sorted thru a big pile and used it as it fitted.

Every length of box section has an internal bolt as as well as the straps holding it all together, a big 6mm earth cable runs from bolt to bolt. This way the earth's to the drop runs only have to run from the nearest bolt to the isolator or socket in the correct loading gauge.

The sockets on the benches run in front, again in steel conduit as I hate trailing leads running over a bench.

http://www.stevenson-engineers.co.uk/files/sockets1.jpg

Just out of the pic on the right is another double plug on the same ring.
The clips we use are high enough to keep the conduit lined up with the knock outs so you don't have to use offsets or put kinks in, note the connecting sleeve next to the clip where I probably have been using up old pieces.
Just a handful of sleeves, ferrule nuts and the die holder. Couldn't be easier and my shop has been changed around no end, in fact non of the pic's show the shop as it is today.

.

Carld
01-01-2009, 08:49 AM
I am not an electrician by profession but have done a lot of it. Having done both metal conduit and PVC conduit I can't see where anyone can say the metal is easier than PVC. It just is not true and there is very little fire hazzard with the PVC. Unless metal is mandated by code or insurance company the PVC is easier for the average person to do.

It may be easy for someone that bends conduit everyday to use metal but the average person would waste a lot of conduit getting it right. Even the pro's make mistakes on the bends.

John Stevenson
01-01-2009, 09:00 AM
Carld,
Why do you need bends, just been out in the shop and taken a look round and there are only 5 bends in my three shops. these are all pre bent lengths of conduit and were used because they were there or the holes were already in the box section with it being used.

There is no reason why all my shops could not have been done with all straight lengths.

The only bend I have that is needed is the one on the front of the bench where it bends 90 degrees to go up the wall to the box and this is done with a screwed elbow that is tighter and tucks away better than a formed bend.
They even have a hinged cover on them so you can pull the cables in two straight pulls as opposed to getting them round the bend.

No reason why PVC couldn't have been used instead of steel, [ except for the hard use bit on the front of the benches ] , just querying why bends are needed ?

.

Stephenwp
01-01-2009, 09:29 AM
I hated working with thinwall conduit until I found offset connectors. They have the correct offset so that boxes and conduit both fit tight against the wall without bending an offset in the conduit.

To offset from the wall into a box, put the bender on the very end of the conduit and make an 8 degree bend. Flip the conduit 180 degress, slide the bender just past the first bend, and make another 8 degree bend. In other words, two opposite 8 degree bends, close together. It's easy, cheaper, and even looks much better than offset adapters. Try it with the handle on the ground and the bending die in the air.

http://images.cableorganizer.com/greenlee/benders/bending_handle-down.jpg

aboard_epsilon
01-01-2009, 09:30 AM
For the three phase i use these boxes ...and re-enforced shilded cables called SY cable
http://img.photobucket.com/albums/v190/aboard_epsilon/workbench/BOX.jpg

http://img.photobucket.com/albums/v190/aboard_epsilon/workbench/FARBOX.jpg

http://img.photobucket.com/albums/v190/aboard_epsilon/workbench/SOCKET.jpg

cont..

aboard_epsilon
01-01-2009, 09:31 AM
some of the cables drop down into multi outlet boxes i made
http://img.photobucket.com/albums/v190/aboard_epsilon/drill/full.jpg

http://img.photobucket.com/albums/v190/aboard_epsilon/trunk4.jpg

aboard_epsilon
01-01-2009, 09:32 AM
whilst the single phase system is here .

http://img.photobucket.com/albums/v190/aboard_epsilon/trunk1.jpg

lighted switch is emergency lights charger
http://img.photobucket.com/albums/v190/aboard_epsilon/trunk2.jpg

3x3 trunking runs full length of purlins
http://img.photobucket.com/albums/v190/aboard_epsilon/trunk3.jpg

all the best.markj

Malc-Y
01-01-2009, 09:55 AM
I am with John Stevenson all the way on this. I too have fitted all of my workshop with secondhand 3/4" steel conduit that I have scrounged from demolished buildings and from work when re-wiring has been carried out. I also have a few bends but they alresdy in the conduit when I obtained it. I mainly use screwed angle pieces and T pieces and cut and thread lengths as required. All my outlets are double metalclad 13amp sockets as shown on the front of John's bench but mine are on the wall with a straight run coming down from the 3/4" ring main running round the workshop at the top of the walls. this is fed from my main consumer unit via a circiut breaker and a residual current breaker to a distribution box in the workshop with two circuit breakers in it, one for power and one for lighting. For my 3 phase supply I use a 10hp rotary phase converter which is fed from an entirely seperate supply from the main consumer unit. I used 10mm 3core SWA (steel wire armoured) cable that I installed myself but had it connected at both ends by a qualified electrician who carried out all the earth tests and issued a safety certificate. At the consumer unit, the power is fed via a 40amp circuit breaker and at the workshop end a two pole 30amp isolating switch and then a flexible conduit to the phase converter. I have several 3/4" conduit dies and stocks that can be had for next to nothing here as the modern standard uses 20mm conduit. Adaptors are available to connect 3/4" to 20mm so a mixture of the different standards is easy although all mine is currently 3/4". I have a total of 7 double 13amp outlet sockets around my workshop, which is 12' x 25', and this is just about adequate, I don't like using extension leads if at all possible.

Malc. :cool:

lazlo
01-01-2009, 10:15 AM
Pardon the interruption, but like any good tool porn, my brain shut down when I saw Epsilon's picture.

What drill press is that? Is that a Vari-speed (Reeve's Drive) feed mechanism, or is it a gearhead?

aboard_epsilon
01-01-2009, 10:44 AM
its a 1930-40s british-thompson-houston/ jones-and-shipman collaboration gearheaded drill press ...the first three phase machine i purchased, about 6 years ago.

cost 100

6 speeds about 40 - 960 rpm mt2.........no power feed .......but makes up for this with its versiltilty ........table winds up and down on substatial ways ....all the way to the bottom..........as well ,that quill head moves up and down about a foot.

it has inbuilt fllood coolant .but is missing pump.

i maybe think it was made during the war ...because the castings are unfinished ..and rough....no filler.

but overall its in nice condition .

http://img.photobucket.com/albums/v190/aboard_epsilon/drill/half.jpg

http://img.photobucket.com/albums/v190/aboard_epsilon/drill/quill.jpg


allo the best.markj

jkilroy
01-01-2009, 11:13 AM
Don't bend the pipe for any 90, put ell's and boxes everywhere, sure makes pulling wire later a lot easier. Never seen that SY cable, don't know if they have that in the states, or if its legal. Closest we have here might be SO cord.

aboard_epsilon
01-01-2009, 11:18 AM
Don't bend the pipe for any 90, put ell's and boxes everywhere, sure makes pulling wire later a lot easier. Never seen that SY cable, don't know if they have that in the states, or if its legal. Closest we have here might be SO cord.

its in a lot of pro shops in the UK ..that are inspected regularly by government inspectors


http://www.tlc-direct.co.uk/Images/Products/size_3/MF6SLASH4.JPG

all the best.markj

J Tiers
01-01-2009, 11:35 AM
J Kilroy.....

The closest we have is type MC cable..... armored cable with a true grounding wire. Available in various varieties and conductor counts.

This is NOT the same thing as the old armored cable that just had the little "tracer wire".

Why would anyone do all the bends for EMT? It has to be supported, but support clips are available that support it at the height of the usual surface box opening.

if you want it against the wall (and I like that best for shops, as do some inspectors), the offsets work fine. or I suppose you can bend it also. I do that. But bending it also limits runs, since the bends may count against the total bending allowed in one run.

Bmyers
01-01-2009, 12:17 PM
http://www.tlc-direct.co.uk/Images/Products/size_3/MF6SLASH4.JPG

we call that VFD cable in the states and it still has to be in conduit

jkilroy
01-01-2009, 12:20 PM
Looks expensive, I'll stick with SO :D

aboard_epsilon
01-01-2009, 12:38 PM
it's not expensive...thats why i use it .. ..it a quid a metre for the 1.5

quid = pound

all the best.markj

Peter.
01-01-2009, 12:59 PM
Got no 3-phase in my workshop but if I did it would be done with the armour cable. It's VERY tough for a flexible cable - we use it to power our demolition robots and they give it a lot of abuse in severe conditions.

Bmyers
01-01-2009, 01:01 PM
Unfortunately the US is not as progressive about new products. That would be great stuff if you can use it non protected

dave5605
01-01-2009, 01:05 PM
I probably mess with EMT conduit once every couple of years. All you need is a EMT conduit bender and about 5 minutes to get productive. I use one of those machinest deburring tools to do the deburring. Many years ago all the electricians did was jamb the handles of their channel lock pliers in the conduit and give a few twists of the head.

Here is a PDF file that gives you lots of info.
http://www.mikeholt.com/documents/freestuff/BendingRoundRaceways.pdf

For your basic 90 degree bends its a matter of knowing how much the conduit length 'grows'. A test bend will tell you. Its different based on the conduit size and your particular bender. Once you have that measurement you can reliably make 90 degree bends all day long and have the length between bends correct.

You can legally (according to 1990 code book I have) put up to 7 #12 wires in a 1/2" conduit or 5#10 wires. That assumes the insulation is type TW. THW insulation allows 4#12 or 4#10 in 1/2" conduit. So changing out #14 wire shouldn't be a big problem (other than the time and wire cost)

THWN and THHN insulation lets you do 10#12 or 6#10. That's because the insulation is thinner.

All those numbers are based on the max fill allowed of 40% for 3 or more wires in the conduit.

Life can be a lot (and I mean a LOT) easier in pulling wires in the conduit if you get some wire pulling compound at you local lowe's/home depot/whatever.

Slop it on (don't be stingy here) the wires as they are being pulled through the conduit. One person slops it on while another 'pulls'.

40 years ago the slang term for the wire pulling compound was 'goose grease'. Very appropriate.

Here is a typical table on wire fill in conduit that you can find on the WWW. I noticed it allows about 1 wire less than I listed above.
http://www.elliottelectric.com/References/Conduit_Fill_Table.aspx

Bmyers
01-01-2009, 01:14 PM
You can legally (according to 1990 code book I have) put up to 7 #12 wires in a 1/2" conduit or 5#10 wires. That assumes the insulation is type TW. THW insulation allows 4#12 or 4#10 in 1/2" conduit. So changing out #14 wire shouldn't be a big problem (other than the time and wire cost)

As you put more wires in a conduit the current rating of the wires has to be derated.

jdunmyer
01-01-2009, 01:48 PM
Another hint when wiring: use the deeper 4X4 boxes, always. There's lots more room to work. Also, when pulling wires, leave yourself plenty to work with, you'll often trim some off when making connections, but it won't amount to a lot in the end, and it's a LOT easier to work with.

One problem with using MC or even plastic conduit is that it must be supported/clamped OFTEN. Even then, the MC will sag and look like crap (to my way of thinking)

I've worked with both EMT and PVC, and the former is no harder to work with than the latter, IMO. Again, IMO, you end up with a better looking job.

If you don't use raceway, use larger conduit like 1" for your main runs, and install junction boxes at appropiate points. When we did the woodshop, we installed 3 large J-boxes upstairs, then ran conduits from there, along the walls, and dropped down into the shop itself. Made a professional-looking job and was easy to do, both the conduit and the wiring.

Cheeseking
01-01-2009, 02:31 PM
I dunno, I'm partial to EMT
What's the saying? Good - Fast - Cheap: Pick any two! :D

datsun280zxt
01-01-2009, 04:56 PM
AS my dad taught me when I was helping him wire stuff around the house/shop when I was younger...they don't make anything smaller than #12 wire...no matter what you see on the shelf at the store, it doesn't exist. I moved and had to wire up a new shop a while back and was very glad to to have listened to him. On the runs that I was told that #12 was okay, but getting towards borderline, I ran #10, and so on. I recently had to purchase a new air compressor, and I was shure glad I ran that larger wire , or I would've been doing it again, because I bought a bigger unit this time.

On the issue of pvc vs. metal conduit vs. no conduit ....metal everytime. I've done the pvc, and disliked it over time as it gets hot in my shop and the stuff just droops too much no mater how well it's supported. I am kinda picky about that kind of thing tho. In the shop mentioned above, I ran everything in the walls, and I already have regretted it a couple of times (and its been less than 2 years). I put outlets everywhere (or so I thought) but realized I needed many more. I'll now be running metal conduit on the outside of my walls to complement my hidden wiring in the walls. The new bigger shop (30x40) will use all metal with minimum 3/4 conduit. Its just seems to be the smart way to go in a shop.

TECHSHOP
01-01-2009, 06:47 PM
First, I do the "electrical math" as per the code, but I want the greatest "peace of mind" that I won't burn a motor up or the shop down.

So, I use the next larger wire size and pull it through EMT "two sizes too big". As much as doing that may add to the intial "cost of the job", it beats the "rework to upgrade" (best case) or "replace a shop full of machines" (worst case) price.

John Stevenson
01-01-2009, 08:05 PM
http://www.tlc-direct.co.uk/Images/Products/size_3/MF6SLASH4.JPG

we call that VFD cable in the states and it still has to be in conduit
Here it is allowed to be stand alone up to 600 volts, that braiding is tough.

It will stand heavy stuff being dropped on it.
On the first post I did that Bridgeport has about 4 meters of that same cable coiled round the ram because it was destined for a move and when it was moved the excess was cut off.

Another slight alteration, after reading Malc y's post I realised that my conduit is the current 20mm stuff, not much difference as it's still available from demo and scrap yards for peanuts as it classes as light iron and isn't worth a lot.

.

tiptop
01-02-2009, 12:00 AM
I would like to say thanks for the responses to everyone. I talked to my buddy down at the building department and he concurred with you folks that EMT was the way to go. I had originally wired the old shop with exposed 12 ga. romex. Then when I started adding machine tools I went with EMT. This time because of costs I thought I would skimp. But you all are right, this is not a place to skimp on.
John I really like your steel box section. I had seen them before but had totally forgotten about them. They call them steel enclosed wireway or auxiliary gutters here. I remember working with them and the ease to open them up and add a run or delete one. It makes the conduit runs short and a lot less bends also. I will be looking for some of this at the local scrappers and on craigs list.

Jay

Steve Stube
01-02-2009, 01:05 AM
I wish you were closer Jay as I bought 40 foot of Square D LDB410KO for my shop build in 1982 and decided not to use it - been storing it since. Thanks for the reminder about Craigslist, maybe I can find a new home for it. I think shipping would be a killer.

Here is a link to Square D WireWay;
http://ecatalog.squared.com/catalog/174/html/sections/13/17413002.pdf

Paul Alciatore
01-02-2009, 01:27 AM
I also would recommend metal conduit.

But whatever kind you use, please do use a real ground wire. Do not ever rely on the conduit or on a shield style conductor for the ground. I have seen far too many conduit runs that had been hit by something and the circuit wires were still completely active while the ground connection was completely lost. Absolutely no protection and no way an operator at a remote location from the break could possibly know there was potential danger. So use real ground wires that are at least as long as or longer than the current carrying conductors. They should not be the shortest wires (the first to tear loose when hit).

rdfeil
01-02-2009, 02:36 AM
Jay,

All good advise above. I just wanted to add a couple of thoughts. I agree and suport the use of EMT conduit in a shop. If you are able to get wireway (also called gutter or trough ?sp) make sure you mount it at least 18 inches down from the celing. This leaves you enough room for the conduit ells to go up to the celing for lights and celing outlets. If you don't get wireway another good option is to get screw cover knockout pulling boxes, get at least 12 X 12 or larger. Mount 3 or 4 of these up near the celing on each wall. Interconnect them with large conduit 1 1/2 or 2 inch. This will give you a poor mans wireway. You can run the main wiring through the large conduit and boxes and come out of the boxes with smallar conduit for the machines and outlets, lights etc. This type of installation also is easy to add to as the large conduit is easy to pull new wires through and the boxes are close enough to everything to make for easy short conduit runs.

Not to be pushy but like has been said several times above.... Run dedicated ground wires to everything. Conduit is just to easy to loosen or seperate and there goes your ground and safety.

Also, use #12 wire as a minimum, this will allow 20 amp circuits and the cost is only slightly higher. Use THHN stranded wire, it pulls much easier and is just easier to work with. You can get diferent color wire if you want to make circuit identification easier. Just remember, green is ONLY for GROUND, and white is ONLY for 120/240 neutral and gray is ONLY for 277 neutral. All other colors are free game to use and it sure makes chasing things easier in the future. Also, it is perfectly legal to pull in more wire than you need to allow for future additions. Just coil it up in the boxes and label it as "SPARE" and do not connect it in the breaker panel, just mark as "SPARE" on that end also.

Good luck,
Robin

clutch
01-02-2009, 02:45 AM
I wish you were closer Jay as I bought 40 foot of Square D LDB410KO for my shop build in 1982 and decided not to use it - been storing it since. Thanks for the reminder about Craigslist, maybe I can find a new home for it. I think shipping would be a killer.

Here is a link to Square D WireWay;
http://ecatalog.squared.com/catalog/174/html/sections/13/17413002.pdf

I'm afraid to ask but what did that stuff cost a foot back then?

Clutch

ckelloug
01-02-2009, 03:08 AM
My shop is all done on MC cable. Our inspection department considers the MC cable equivalent to conduit and it is rated for commercial applications whereas Romex is not. MC is easier to deal with than conduit and it might be worth looking into if your insurance guys accept it the way our inspection department sees it.

John Stevenson
01-02-2009, 04:48 AM
Jay,

Not to be pushy but like has been said several times above.... Run dedicated ground wires to everything. Conduit is just to easy to loosen or seperate and there goes your ground and safety.

Good luck,
Robin

At one time in the UK it was allowable to use the trunking for earth, this was then changed in later regs for true bonding which is far better.

Our old truck garage was wired to current spec of the time by the electrical board as a contractor, later in years it was possible to get belts off some of the sockets because the slight corrosion on conduit to trunking joints were breaking the path down.

Trunking still has to be bonded but not allowed to be used for earth return. What most people do is what I have done and that is to install an earth ring in heavy cable from the Dizzy box to the first bonding point, then link to the next, then the next etc until you come back to the dizzy box.

This was you can get away with using short runs of lighter earth from the isolators or sockets to the nearest bonding point instead of having to run all the earth's back to the dizzy box.

Quicker, less cable and doesn't cram the trunking up as much.

.

J Tiers
01-02-2009, 10:46 AM
Unfortunately the US is not as progressive about new products. That would be great stuff if you can use it non protected

It is NOT progressive to allow unprotected cable in an area exposed to damage...... And the Brits complain about OUR wiring and say it's unsafe...... :rolleyes:

This is a poster-picture of "exposed" wiring in an "industrial" setting...... Would never be allowed here.


http://img.photobucket.com/albums/v190/aboard_epsilon/workbench/FARBOX.jpg

aboard_epsilon
01-02-2009, 11:12 AM
It is NOT progressive to allow unprotected cable in an area exposed to damage...... And the Brits complain about OUR wiring and say it's unsafe...... :rolleyes:

This is a poster-picture of "exposed" wiring in an "industrial" setting...... Would never be allowed here.

That's a shed

Im a diy / amiture

as above, the stuff is used for bomb disposal vehicals ..how much tougher do you want.

all the best.markj

J Tiers
01-02-2009, 11:43 AM
That's a shed

Im a diy / amiture


Same difference..... I see machines...... and "exposed" wiring is 'exposed' wiring.

Even here, you can do that with EMT (thin wall conduit), but you may not be able to do it with armored cable, let alone non-metallic cable.

it would be required to run the NM cable down the SIDE of the vertical stud, for partial protection. Bored holes would allow it to pass through the studs, and if the stud were not deep enough, there would have to be a protective plate on the surface if the wall were enclosed (to prevent pounding a nail into the cable).

John Stevenson
01-02-2009, 12:10 PM
And the Brits complain about OUR wiring and say it's unsafe...... :rolleyes:



We don't complain about your wiring, only the way you wire it :D :D

.

J Tiers
01-02-2009, 12:31 PM
We don't complain about your wiring, only the way you wire it :D :D

.

better look around at home, then...... if that exposed "NM type" cable is an example......

it looks like typical flex cord construction, which is not allowed to be used for wiring here... just as flex cords.

aboard_epsilon
01-02-2009, 12:37 PM
nm type cable wtf is that .......

the grey cable you see in the picture was temp wiring ........at the time off pic.

Boring holes in them studs with that diameter of SY-cable would seriously weaken them .so you have a (maybe) safer electrical system or a structurally unsafe building ..i had the choice.......this shed is not the main building its not used like the main building ..

This is an amiture forum populated by manly amiture machinists.........some don't have the cash to go full out on a no holds barred super safe working environment and have enough cash left to full-fill their hobby at the same time....you got to draw the line somewhere ...

It's safe enough for me ...I built and installed it all ......I'm not going to stick nails through it ...

BTW nearly every amiture machinists workshop I've visited in the GB .. are atrocious as regards safety issues .........

Things I've seen in most

One single 1mm flex suppling the whole workshop from the house .

Dangled extension leads with double adaptor plugs in double adaptor plugs ..

Lighting connected to the extension leads........with no switching ..plugging in turns on the light.

Twin core and earth non flex cable laying across floor to supply and the power to machines.

if you chose 10 UK amiture workshops at random and compared with mine ..and ordered them into most safest ...then mine would be 1st or 2nd in the rankings for safest.....

There are probably a lot of people here, viewing this thread that are in the same predicament as I ...that is, don't have two pennies to rub together .........you make do with what you have and can afford..and do it as safely as you can afford... .....we are not all rich and well off .

all the best.markj

John Stevenson
01-02-2009, 12:51 PM
It would be required to run the NM cable down the SIDE of the vertical stud, for partial protection. Bored holes would allow it to pass through the studs, and if the stud were not deep enough, there would have to be a protective plate on the surface if the wall were enclosed (to prevent pounding a nail into the cable).
You may know what NM is ? non metallic ?, we don't.

So what stop you pounding a nail thru a PVC pipe and into a live cable ?
That cable Mark has shown is quite robust, plus the external braid is bonded to the earth so if you were clumsy enough to drive a nail thru it, the nail would be earthed before it hit the conductor, result is the RCD trips.

.

barts
01-02-2009, 01:11 PM
You may know what NM is ? non metallic ?, we don't.

So what stop you pounding a nail thru a PVC pipe and into a live cable ?
That cable Mark has shown is quite robust, plus the external braid is bonded to the earth so if you were clumsy enough to drive a nail thru it, the nail would be earthed before it hit the conductor, result is the RCD trips.

.

In the US, most circuits are not on ground fault interrupters, which detect any leakage current to ground and trip.... is this also true in the UK? Or are all breakers GFI ?

- Bart

aboard_epsilon
01-02-2009, 01:18 PM
The tailings from the meter first go through an RCD......then each circuit /ring-main is protected by mcb.

all the best.markj

john hobdeclipe
01-02-2009, 01:25 PM
Here in Collin County, Texas, it's OK to use "flex" or "Greenfield" armored cable for exposed work in the shop, so that's what I have. Adding circuits as needed is quick and easy. Our insurance carrier never asked anything about the wiring...I guess they figure that whatever is OK with the county inspector is fine with them. Of course, If the shop were literally a commercial, money making enterprise, perhaps the insurance people would want to come out and look.

Only real downside to using this is that it isn't very good looking. But then again, neither am I.

barts
01-02-2009, 01:55 PM
The tailings from the meter first go through an RCD......then each circuit /ring-main is protected by mcb.

all the best.markj

I guess those of us in the States use different terminology... from a bit of googling, an RCD is the same as a GFI; evidently previous practice was to use one for the whole house, but this is no longer permitted, apparently.

And an mcd is a circuit breaker....

http://www.diydoctor.org.uk/projects/consumer_unit.htm

Thanks for the info -

- Bart

aboard_epsilon
01-02-2009, 02:06 PM
I've got three rcds ...there is a mcb box for the shed with rcd, same mainworkshop..but that was a total waste of time........as when i do make mistakes it trips the one for the main power at the house every time.

been thinking of bypassing the main one and suppling unprotected by main rcd.........just big mcb up to the main workshop and shed.....so the rcds work on their own independently in the workshop and shed..,

all the best.markj

John Stevenson
01-02-2009, 03:22 PM
We have a slightly different system in the UK and in fact all over Europe, Australia and the Far East.

It's 220 to 240 volt depending on location and regs, AC, that one live, one neutral, no split phase system.
earth is bonded to neutral on the electricity boards side of the meter.

Usually the incoming underground armoured cable has the armouring [ Earth ] and neutral bonded, they are also bonded at the sub stations as well.

They actually run three phase 440 volt everywhere in the UK, just taking our house as an example which is purely single phase [ the workshop is on a separate metered supply ] the main 3 phase cable runs from the nearest substation in a big ring back to the substation.

There might be from 3 to 10 rings depending on the size of the substation and how the buildings were developed over the years.

Cable is colour coded red, blue, yellow are phases, black is neutral, earth isn't in the cable but is present in the armoured wire.

Any phase to neutral is 220 - 240 volts and phase to phase is 440 volts.
So the first house get connected to red and black, second to yellow and black, third the blue and black and 4th back to red and black to equal the loading out.
This way running 440 volt three phase they can use smaller cable than if it was all on the same single phase ring.

In the UK it's possible to get a temporary true 3 phase supply by throwing an extension lead over to both neighbours and using their live phases and yours :D Also depends on the neighbours.

.

Steve Stube
01-02-2009, 03:30 PM
John, how close are your neighbors? and is that third phase across the road?

John Stevenson
01-02-2009, 03:47 PM
Close, everything in the UK is close :) if you have a large gap between yourself and your neighbour then he's in another county :D

Older properties in town probably have a pathway divides them, newer with garages have a driveway dividing them, some a double driveway but land is expensive here and at a premium

As to how the cables run it depends on location, on our road there is a cable runs up both sides of the road but not the same cable. Once we had a power cut but across the road didn't. This is an old area though so it's probably criss crossed with cables.

.

Steve Stube
01-02-2009, 05:16 PM
Thank you John for explaining, interesting.

Jay, now that we know my wireway has been stored far too long (e-mail w/picture sent) I will attempt to show you what I ended up doing instead. Nearly all my wiring is in the 2X6 stud spaces and floor joist but there are a few places that wouldn't have electrical service without running some conduit. One example is at the support posts. I know the photo is busy but somewhere in the middle you will see a 4" sq. steel post. I fed these boxes at the ceiling with 120 (20 amp), 240 (20 amp) and #8 3c/wg. The boxes are small and tight but workable. Bigger is better but I made it work in the 6X's even with # 6 romex triple pigtails in one spot. I used the screw lid boxes downstairs but I like the hinged door models a little better and used them at the second floor posts where they have the same power feeds. It is easy then to drop down the post with whatever you need. I have not even tapped into the #8 wire yet but it is there when the need arises.

http://img.photobucket.com/albums/v19/ceethese/Posted%20photos/Shoprandom12.jpg

tiptop
01-02-2009, 08:41 PM
Steve, thanks for the effort. Jay

J Tiers
01-02-2009, 11:54 PM
You may know what NM is ? non metallic ?, we don't.

Defined in a prior post... you must have missed it.

Yes. NM = non-metallic sheath cable also known as "Romex" which was a widely used brand. Generally resembles A-E's gray cable but is usually flat and has no shield braid. Only allowed in protected areas, run thru studs well below the wall surface.

other common types used here include:

"BX" cable, which is a prior type of flexible armored cable which used the armor as ground (obsolete now)

"MC" cable, like BX but has a dedicated earthing wire in it (replaced "BX"}

"conduits" include

"Greenfield", which is a flexible armor tube similar to type MC, thru which wires can be run where they must be flexible.

Various water-tight versions of "greenfield"

PVC conduit, "Non-metallic conduit". Good for areas where metallic conduit would be corroded, but NOT good for areas exposed to damage.

"EMT", or electrical metallic tubing... pretty similar to what you have in your shop.... OK for exposed work. Connections use fittings to attach into boxes etc. Can be weathertight or not, depending on boxes and fittings.

"conduit", which is just like water pipe only smooth inside.... approved for anything, basically, depending on corrosion conditions. Connections are screwed like pipe. Watertight, weathertight, OK for areas where flammable vapors are present, if the pipe is filled with a sealant where it exits the area.



So what stop you pounding a nail thru a PVC pipe and into a live cable ?
That cable Mark has shown is quite robust, plus the external braid is bonded to the earth so if you were clumsy enough to drive a nail thru it, the nail would be earthed before it hit the conductor, result is the RCD trips.

.

That's a point, and one reason I don't like PVC conduit. Although it's surprisingly hard to pound a nail into.... it skids off.

That braiding looks pretty loose and open, you might miss it..... probably not though.

Still, not allowed here.

ckelloug
01-03-2009, 12:25 AM
What JT's calling conduit is formally called either RMC: Rigid Metallic Conduit or IMC: Intermediate Metallic Conduit. There are tiny differences but like he says, it resembles cast iron water pipe.

wierdscience
01-03-2009, 12:42 AM
NM sheild wire is frowned on the instant it's tacked to an exposed wall.

However SEOW rubber cord is allowed to be used as a machine drop from either metallic conduit or bus-duct so long as the drop isn't over 12' in length and features a strain relief on each end.OSHA also requires a saftey disconnect switch within 25' of the machine the circuit is powering.

Here no NM cord or conduit is allowed over 220v(fire hazzard)everything over 220v is piped in metallic ridgid conduit.

That is for industrial applications.At home things are different.From having a rat inside a wall once that stripped three pairs of Romex to bare copper,Greenfield 12/3 or metallic conduit is it for me now.

J Tiers
01-03-2009, 01:50 AM
I quite appreciate the idea of low cost operation for the home shop type.....

I am a bit surprised though, since I understood it was illegal to do your own electrical over there, had to be done by approved electricians. So i would have supposed that shops and so forth would still be wired per all codes etc.

I do like the monster connection plugs in your shop though..... I've seen those before. Quite sensible, and better than some we have. I think they are actually UL listed and may be available here, but they are very spendy here.

Maybe the codes differ... as wierdscience mentioned, we would not allow the "NM" cable, or flex cord either, to be stapled on the surface like that. Flex cord can't be "permanently installed" like the "NM" cable.



We have a slightly different system in the UK and in fact all over Europe, Australia and the Far East.

It's 220 to 240 volt depending on location and regs, AC, that one live, one neutral, no split phase system.
earth is bonded to neutral on the electricity boards side of the meter.

Usually the incoming underground armoured cable has the armouring [ Earth ] and neutral bonded, they are also bonded at the sub stations as well.



As you are probably aware, the US 240V split is very similar, but has a lower voltage to ground for common circuitry, while preserving the higher voltage availability where needed.

Incoming is bonded to ground rod, earthing (green) wire system, and back to the transformer on the pole, as well as the earth system at each pole.

Distribution is usually at a high voltage, 2200 to 7000 volts, and each group of maybe 4 or 5 houses has a common transformer.

basically the same system, but a bit easier on the neutrals since if the loads are reasonably equal on both 120V, the neutral current is low. Still has to be same size wire, though.


Here no NM cord or conduit is allowed over 220v(fire hazzard)everything over 220v is piped in metallic ridgid conduit.

Interesting.... We have 440V 100A run all over in EMT..... perfectly acceptable.



What JT's calling conduit is formally called either RMC: Rigid Metallic Conduit or IMC: Intermediate Metallic Conduit. There are tiny differences but like he says, it resembles cast iron water pipe.

IMC is also threaded, but not as heavy as RMC.

The EMT cannot be threaded, you make all connections with fittings.

SDL
01-03-2009, 04:07 AM
I quite appreciate the idea of low cost operation for the home shop type.....

I am a bit surprised though, since I understood it was illegal to do your own electrical over there, had to be done by approved electricians. So i would have supposed that shops and so forth would still be wired per all codes etc.

I do like the monster connection plugs in your shop though..... I've seen those before. Quite sensible, and better than some we have. I think they are actually UL listed and may be available here, but they are very spendy here.



Over here you can still wire your own house or Workshop but it is meant to be inspected by a competent tester.

The differences being argued about here relate mainly to the difference between home shop and commercial wiring. Having commissioned equipment for drinking water plants in the UK and in Denver, Houston, Henderson, Cincinnati and Johns town USA I have seen a lot of both countries systems.

The CY type cable is intended as a flexible cable in Robotics and machine linking etc., it has replaced a lot of flexible conduit work and is available with up to 50 cores. http://www.eland.co.uk/electrical-cables/control-flexible/cable36/cy-control-cable.html. I have used it in by home shop as the cable from my mill to the outlet.

In full industrial situations the UK used to mainly use the square trunking with the removable lids that John showed, this would have conduit drops to isolators for machines etc. This has been superseded in most indutrial installations by armoured cables ( http://www.eland.co.uk/electricalcable/armouredcable/cable62/steel-wire-armoured-swa-bs6724-cable-lszh.html )on Cable tray.
I never have seen a site in the UK done with the big conduits (2" plus) used in the US.

At work we never used to understand why the consultants on US jobs wanted all the wiring details so early in a project before we had designed our equipment until i went to site and realised they put a lot of conduits under the slab and needed details before the foundation pour. In the UK it wasn't a problem until the shell was up.

The CY cable has been used in the US as we have shipped equipment using it between control panel and equipment but not as fixed power wiring.

Steve Larner

wierdscience
01-03-2009, 09:42 AM
Interesting.... We have 440V 100A run all over in EMT..... perfectly acceptable.

.

"ridgid metallic" here means anything but flexible conduit,greenfield,BX cable etc.The code here uses the term to pin down the definition.

The other loop hole are cords.We can only have a 12' cord drop,but we can have a 100' cord so long as the gauge/plugs are all to spec.

That's a common cheat here,conduit to an outlet box,then a cord from there.

J Tiers
01-03-2009, 11:06 AM
In full industrial situations the UK used to mainly use the square trunking with the removable lids that John showed, this would have conduit drops to isolators for machines etc. This has been superseded in most indutrial installations by armoured cables ( http://www.eland.co.uk/electricalcable/armouredcable/cable62/steel-wire-armoured-swa-bs6724-cable-lszh.html )on Cable tray.
I never have seen a site in the UK done with the big conduits (2" plus) used in the US.

At work we never used to understand why the consultants on US jobs wanted all the wiring details so early in a project before we had designed our equipment until i went to site and realised they put a lot of conduits under the slab and needed details before the foundation pour. In the UK it wasn't a problem until the shell was up.

Steve Larner

Busway is pretty common here, that is pre-wired sections of heavy solid conductor, braced against fault current forces, etc, often rated at 400A or more. Drops from it are via boxes that plug in at designated locations every few feet, with disconnect and fusing. Run busway down the middle, and take off drops as needed. Machines are easily moved, changed etc.

The "Wiring duct" is also common. But there are limits on fill, and wires must be de-rated for current due to having a lot of them in one enclosure.

if the positions of things are known and constant, conduit is used, in slab or not. if it is known that machines will be in a certain area, but that they will change, be moved, etc, busway is often used.

Ladder cable tray also.

jdunmyer
01-03-2009, 11:39 AM
Bussway is really nice, but FAR out of reach of the average home-shop guy. Unless you happen to be in the Right Place at the Right Time, so to speak, and you had better get all the buss plugs (swing jacks) you're going to need at the same time.

Wiring duct isn't quite so out of reach. :-)

John Stevenson
01-03-2009, 11:44 AM
You need tall ceilings as well for a bussway, the connectors they use here stick out a foot and the bussway is about 6" deep.

.

tiptop
01-03-2009, 11:57 AM
Hi All,
I think I have found 150' of 2-1/2" X 2-1/2" used wireway. I should know in a week or so. This should work well, I will have to cut it to go around a couple of corners but laying wire for runs will be easy.

Jay

J Tiers
01-03-2009, 08:22 PM
Bussway is really nice, but FAR out of reach of the average home-shop guy. Unless you happen to be in the Right Place at the Right Time, so to speak, and you had better get all the buss plugs (swing jacks) you're going to need at the same time.

Wiring duct isn't quite so out of reach. :-)

Oh, heck.... Busway isn't very useful to the HSM....... the quote in my post mentioned industrial stuff......

Even wiring duct is pretty much overkill for the HSM, but it is at least useful.... You DO need to upsize at least one gauge of wire to avoid limiting yourself due to having "more than 3 wires in a raceway" (meaning current conducting wires).

I'd just wire up with type MC, or EMT, and go (see earlier post for definitions). Type MC is much easier to move around later, so I prefer that for anything with a chance of being changed..