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View Full Version : OT- T5HO electronic ballast: Will it function without dedicated ground?



chipmaker4130
04-15-2013, 05:52 PM
The new solid-state ballasts are new to me. Since I couldn't afford to install high intensity lighting throughout my shop, I decided to mount a couple of 4' 4 tube T5HO fixtures on a trolley for the top rail of my crane. Then I can move the 'bright spot' to any point in the shop! The trolley and lights are mounted, and they allow the chainfall to pass unobstructed underneath. The Phillips ballast instruction sheet says the unit must be grounded for proper operation, but the retractable cord reels I got only have two conductors. (Didn't notice that since the source cord is a three-prong unit) The units could ground through the bearings, but they're riding for now on a painted surface. Adding a real ground would be a pain. What do you think? Thanks.

http://i156.photobucket.com/albums/t18/chipmaker4130/0415131526_zpsbfc31bdc.jpg (http://s156.photobucket.com/user/chipmaker4130/media/0415131526_zpsbfc31bdc.jpg.html)

http://i156.photobucket.com/albums/t18/chipmaker4130/0415131526a_zps9c89db57.jpg (http://s156.photobucket.com/user/chipmaker4130/media/0415131526a_zps9c89db57.jpg.html)

macona
04-15-2013, 06:06 PM
They will work just fine. 8 lamps is a heck of a lot of light. 4 lamps is equal to a 400 watt metal halide.

chipmaker4130
04-15-2013, 06:40 PM
Thanks Macona. I'm going to wire them up for either 2 or 4 bulbs per fixture since that's already a feature of the ballast. What I'm hoping for is enough light with everything on to weld stuff without flipping up my helmet for each start! I have a nice auto-darkening 3n1 helmet but unless I'm outdoors in daylight I still can't see well enough.

MaxHeadRoom
04-15-2013, 06:42 PM
Depends if you are concerned with safety and operating within the code?
Max.

chipmaker4130
04-15-2013, 10:57 PM
Hi Max. I do care about safety. The rails and beam are grounded but the trolley and lamp fixtures are not. They are 10' off the floor and the grip for moving them is non conductive. This is a home project which doesn't require a building permit and in my area that makes compliance with code optional.

lakeside53
04-15-2013, 11:46 PM
You can have optional complience with the NEC? What does your insurance company think about that?

chipmaker4130
04-16-2013, 12:08 AM
I didn't ask them! Around here, if a job on private property for private use is done by a paid contractor or if it requires a building permit (and therefore inspections) compliance with code is mandatory. For me, in this case, I'm the only one responsible for my safety. What a concept, eh? In addition, this is not a 'hard wired' installation. Its more like a drop light on an extension cord. Although I haven't entirely given up on working out a way to ground the fixtures I am confident they will be safe enough as they are. Failure of the ballast is not likely to allow leakage and the wiring and sockets are top quality, not to mention the fact that I'd have to make contact with the unit after an isolation failure. I suppose I'm playing the odds a little, but the odds are, in my opinion good enough for now.

darryl
04-16-2013, 12:59 AM
I've always wondered why there isn't more use of extremely bright spot lights for welding. I suppose that once you get an arc started, you have all the light you need. But wouldn't it be handy to be able to see what you're doing through the visor before you strike an arc?

dp
04-16-2013, 01:30 AM
If you have too much light the helmet will darken. :)

This actually reminds me of a story and since I wrote the story I'm going to link it here again. Pretty much my first MIG experience. What could go wrong?

http://hawglydavidson.com/vbgstories/how_hard_could_it_be.html

Barrington
04-16-2013, 05:39 AM
The grounding requirement isn't all about safety. It's also necessary to to reduce emissions, both radiated and back through the power leads.

Also, without a grounded fitting, lamp starting may be compromised, and it's possible that the auto cutout at end of lamp life may occur much earlier.

While the safety aspect may seem unimportant with the lamps out of reach, the heavy filtering required on these electronic ballasts results in significant leakage to chassis/ground. This can give an alarming jolt in the right circumstances - without any fault being present.

In a few years time when the lack of grounding is long forgotten and you're up a stepladder and your bare sweaty arm brushes against the fitting... what will you drop and how far will you fall ?

Cheers

.

Stern
04-16-2013, 08:28 AM
OK, may be a wee bit of work, but how about this. Secure to the top of the beam, a copper strip (which would be grounded) and have a "springed" arm "wipe" the plate to form a "movable" ground contact. Would solve the grounding issue and not effect movement.

OR

Just run a separate ground wire along the power cable you already have.

J Tiers
04-16-2013, 08:32 AM
Regardless of the folks derailing this discussion into a *safety nazi* discussion, if the manufacturer suggests that grounding is needed "for proper operation", they *may have* some reason why they said it..... and reasons why they said "for proper operation", and not "for compliance with safety regulations".

back when nothing was grounded, fluorescent lights worked fine..... it's perfectly possible that the issue is mostly emissions. But that isn't just a minor consideration, and besides, the lights DO usually start better with a grounded case. Right now, you are depending on the filter to "ground" the case to the neutral line.... might, as Barrington says, affect lamp life, etc.

Electronic ballasts can be fussy, as well as being noisy, blasting the entire area with intense EMI even when the (usually minimum possible) EMI filters are in place.

MaxHeadRoom
04-16-2013, 10:16 AM
I guess I come under the title of Safety 'Storm Trooper', back when florescent's were 'not grounded, they were not electronic.
Have built a couple of electronic ballast based on the commercial style, the common circuit is a DC supply followed by a DC to HF AC convertor, whether the manufacturer builds isolation into the convertor varies.
Electronic ballast do not necessarily need a earth ground to operate, as born out by the many portable DC type available which are built exactly the same way as their mains counterpart.
Some studies done in the past have put 50/60Hz fluorescents in a 'noisier' class than most electronic!.
Incidentally when Flourescents were first introduced in the UK and used on the factory floor, the pronounced 50hz flicker caused some accidents due to the stroboscopic effect making the rotation of a tool appear stationary, the
cure was to wire the fixtures in 3 phase banks.
Max.

chipmaker4130
04-16-2013, 12:41 PM
I appreciate all the info. So perhaps there is an operational element to the requirement for ground? The mfg data lists grounding in two separate parts of the document: 'troubleshooting/proper operation' and 'safety'. That's why I asked the question. I have considered various ways to implement a good ground, the one Stern mentioned is where I was headed. I was, however, thinking about a solid copper strip or bar. Very expensive. Just now it occured to me that I could use some of the rigid copper tubing around the shop as the conducting rail on top of the beam. That may be better in that I could arrange the wipers to the side or even slightly under the curve to avoid bad contact due to dust and dirt! When I get home this weekend I'll pursue that.

garagemark
04-16-2013, 01:17 PM
You could also use aluminum strips. Would be much cheaper.

Toolguy
04-16-2013, 01:24 PM
Maybe you could use a spring loaded contact to run on the bottom of your pipe/bar/ground rod.

MaxHeadRoom
04-16-2013, 01:27 PM
Any chance you can replace the 2 cond. to 3 cond. cord?
Max.

chipmaker4130
04-16-2013, 01:33 PM
Max, I'd like to do it that way but the retract reels were supplied with only a 2 slipring/brush assembly. While modification is possible, there would be way too much time and expense involved.

chipmaker4130
04-16-2013, 02:41 PM
. . .This actually reminds me of a story. . .http://hawglydavidson.com/vbgstories/how_hard_could_it_be.html

Great story, and well written. Thanks!

rohart
04-16-2013, 06:00 PM
I built myself a swing out and over 300W lamp for my bench for welding, but eventually I gave up on autodarkening helmets. Partly because they kept flashing me, and partly because I thought I'd see better with fixed lenses. I was right.

So I made myself a good pedal, with variable ranges and a switch incorporated. It runs through a bench box that turns it off too. So my procedure is: get fairly comfortable, get foot ready, set electrode dead right, make sure foot switch is off, turn on bench top switch, flip visor down and hit the foot switch.

As well as seeing better, the number 8 is no more expensive than the others, while an autodark down to 8 gets pricey. The better you get, the fewer times you have to stop to clean up, too.

But I like the light anyway. I've got 5 four ft tubes in my single garage, and it's not enough.

Don Young
04-16-2013, 09:30 PM
Many flourescent tubes rely on internal starter electrodes positioned near the glass at the ends of the tube. These first ionize the gas with a high intensity field from the electrode to the grounded body of the fixture rather than completely from end to end. With this starting system, starting can be absent or intermittent if the fixture is not grounded. I have some of these fixtures and went through a lot of unnecessary troubleshooting trying to get them to start reliably before I found out about the need for grounding.

macona
04-17-2013, 01:12 AM
Yes, some lamps will only fire up in proximity to a reflector, they need the capacitance of it to light up. In situations like signs where the tube is suspended in mid air they run a strip of meta ribbon suspended next to the tube. In the U lamps seen in a lot of 2'x2' fixtures they have a metalized strip that is on the glass itself to help with ignition.

But with the standard programmed start T5 ballasts I have never seen this issue. I have ran them in my aquarium even suspended quite far from a reflector. I had 6 T5HO lamps plus a 175w metal halide on my 120 Gal salt water tank.