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View Full Version : OT: setting up to power the heat from a generator without backfeeding or switching



gellfex
11-29-2012, 10:09 PM
In the aftermath of Sandy I realized I had no good way to power the boiler from the generator extension cord, so I simply tore down the switch box, disconnected the feed from the panel and wired on a cord with a plug. I'm thinking the simplest thing to do is just make the cord permanent and wire the power from the panel to a receptacle, so I can simply pull the plug out and connect it to the generator when the need arises. I figure the boiler safety switches should be downstream of this connection so they would work when connected to the generator too.

Is this well conceived, or wildly illegal to have a cord permanently part of the gas boiler circuit? For complex reasons a generator transfer switch for the panel would not be a good solution here.

loose nut
11-29-2012, 10:30 PM
People do it but it can be dangerous for the lineman fixing things. I have been told that dangerous levels of power can leak out through the ground??? Can't say to the validity of that, best ask an electrician about it. I believe that is why they use disconnect breakers made that purpose.

Duffy
11-29-2012, 10:45 PM
Feeding through your panel without transfer switch is A BAD THING! If the utility linemen find out, (NOT the hard way,) they will likely do evil things to you.
However, wiring your boiler, (I assume it is gas-fired,) through a dedicated receptacle seems reasonable. Possibly STRANGE in the eyes of conventional thinkers, but your fridge, freezer, microwave, even your stove or welder have dedicated receptacles. When you have to rely on your generator, you just plug into cords from it. If your generator cannot handle the WHOLE load, then you have to develope some system of rotation for the appliances. I have seen freezers and frigs run on the equator and they only got power about 4-5 hours in the evening each day. This was routine practice, but it DID require a certain level of discipline, (no checking to see if the frig light works!)

Wheels17
11-29-2012, 11:08 PM
When we purchased our house, it already had a two pole double throw switch box, overrated for the job at 30 amps, wired in the furnace circuit. The panel feed is connected to one set of contacts, and there's a short pigtail with a plug hanging out of the bottom of the box on the other poles. Both the neutral and the hot are switched. The grounds are not. Don't know whether it would be legal today for a new installation, but it certainly is easy to connect and safe for any linemen that are working on the system.

When we lose power, I set the generator out up front and run a long 12 gauge cord from the generator, through the cat door, and down to the box. Plug it in, throw the switch and go. I also run a cord in to the refrigerator, and one to a carbon monoxide detector near the cat door.

The carbon monoxide detector is very important. We got hit with an ice storm a few years ago and lost all power for several days. I had been running the cords in through the front door with the generator about 15 feet away from the door. The setup worked fine for 2 days, on the third day, the alarm went off. The wind had shifted, and even thought the generator was well away, the exhaust made it's way in through the crack. Never had the problem using the cat door.

I did upset my wife, though. She said "Oh well, guess I can't do the wash". There are six receptacles on the generator and plenty of extension cords. 2 more through the cat door and the washer and dryer were working too!!

gellfex
11-29-2012, 11:30 PM
Feeding through your panel without transfer switch is A BAD THING! If the utility linemen find out, (NOT the hard way,) they will likely do evil things to you.
However, wiring your boiler, (I assume it is gas-fired,) through a dedicated receptacle seems reasonable. Possibly STRANGE in the eyes of conventional thinkers, but your fridge, freezer, microwave, even your stove or welder have dedicated receptacles. When you have to rely on your generator, you just plug into cords from it. If your generator cannot handle the WHOLE load, then you have to develope some system of rotation for the appliances. I have seen freezers and frigs run on the equator and they only got power about 4-5 hours in the evening each day. This was routine practice, but it DID require a certain level of discipline, (no checking to see if the frig light works!)

The thing that makes this setup a little more peculiar than just a dedicated outlet is that I propose feeding the power from the plug cord through the circuit for the local and top of the stairs boiler shut-off switches. If those switches are there for safety, might as well use them, no?

I did as you describe in the tropics for the brief 30 hrs we were without power during Sandy, just ran the genny till the handy digital readouts on the fancy fridge read back to normal temps, then shut it off for 8 hrs or so. Except for the while on the 2nd night I just wanted to watch TV and see what was up! At least I wasn't disturbing my neighbors since the massive diesel generator at the school next door had been roaring continuously, drowning out my measly 5500W unit.

LKeithR
11-30-2012, 12:59 AM
I have my generator set up in a container which I use for a small shop and storage purposes. I wired a sub-panel into the container and installed a 30 amp breaker which feeds a 3-prong male receptacle. The sub-panel in the container is fed from the main power panel which means it's directly connected to all the power on the property. When the power goes out I throw the main breaker, isolating our system from the grid, open the container doors, start the generator and connect it to the plug with a cord, throw the breaker on the sub-panel and, voila!, I have power throughout our entire system. No need to run cords anywhere else. My generator is only a 6500 W so we do have to stagger the load but otherwise it works really well...

oldtiffie
11-30-2012, 01:08 AM
I would not even consider doing any of what is proposed or done. I'd have Licenced Electrical Conractor sort it out.

J Tiers
11-30-2012, 01:21 AM
I would not even consider doing any of what is proposed or done. I'd have Licenced Electrical Conractor sort it out.

D**n , you ARE a prissy S*B sometimes........ a real stickler for rules and regs. You should have been an MP.

You do what you have to do to deal with what the reality is at the moment. Rules and regs are all very well, but in many cases they stop applying in exceptional circumstances.

After a storm, your "licensed and certified professional nose-blower" will have his own problems, and won't be really interested in having you call him up on the phone (which doesn't work) so he can drive over to your place using gas (which he cannot buy because the pumps do not work) that he needs for his genset, over roads that are blocked by flooding and downed trees, power lines, etc, to do your work. He can get all the work he needs or wants without leaving his own neighborhood.

darryl
11-30-2012, 01:34 AM
I like the idea of having a receptacle fed from the main panel into which the desired load is then plugged. If you could isolate the fridge circuit the same way, that would be good also. There may be some kitchen lights wired along with the socket the fridge plugs into, and that's your way to keep the fridge working, plus have some lights in the kitchen, without having to have the generator feeding the main panel. There is no chance that a failure to flip a breaker or switch would put the main panel live. If you have to physically pull a plug out of a socket and push it into another one, or an extension cord from the genny, then the action is equal to that of a transfer switch, without the cost of installing a transfer switch. It may be an unusual way of doing it, but it does prevent your own generated power from ending up at the main panel.

I think you would want to mount a few receptacles near the main panel which are fed from your genny, plus one light socket that's hard-wired. Put a long life, low wattage bulb in there. You'll know when the genny is running, plus it automatically gives you light to see by as you transfer the plugs from the important loads. You can always run an inside extension cord from one of those receptacles to power up some other thing if need be. I'm imagining that the wire from these receptacles is permanently run and is accessible from outside, probably coiled up on a rack like your garden hose, ready to plug into the generator. No need to go fishing through windows, etc, to get your power inside.

A grey area for me would be what kind of wire to use for the plugs. It will have to feed the runs of house wiring somehow, so the house wiring (furnace circuit, fridge circuit) would have to go into a junction box, but then a short length of flexible wire with a plug on it would have to exit the junction box. Not sure of the legality of that-

lakeside53
11-30-2012, 01:43 AM
The OP asked if he could put a plug on his bolier so he could plug it into a generator. Sure. But... now the rest of the house is being contemplated by others. Some of of what us being discussed is fine, but... just put in a generator panel in and be done with it. It takes about 4-5 hours for a basic 8 circuit panel and generator inlet (some are part of the panel), maybe 6-7 hours for a 16. It's not expensive, and really not difficult - they sell them for "end-user installs". You of course may require a permit in your area. ;)

EVERYONE in my neighborhood has one! We don't need a hurricane to loose power -175 foot tall trees see to that at 40mph.

$249 for a 6-10 circuit 20 amp; $399 for a 8-16 30 amp.
http://www.homedepot.com/Electrical-Breakers-Distribution-Load-Centers/GenTran/h_d1/N-5yc1vZ1xg1Zbm0kZ4pb/h_d2/Navigation?langId=-1&storeId=10051&catalogId=10053&ef_id=JLdPaVLJL38AAA@l:20121130063955:s&cm_mmc=SEM|RPM&skwcid=TC-14433-6157610799-bb-646577005#/?c=1&4pb=4pb

lakeside53
11-30-2012, 01:48 AM
..... A grey area for me would be what kind of wire to use for the plugs. It will have to feed the runs of house wiring somehow, so the house wiring (furnace circuit, fridge circuit) would have to go into a junction box, but then a short length of flexible wire with a plug on it would have to exit the junction box. Not sure of the legality of that-



That is illegal... or put it this way -try getting it inspected and permitted! It's one thing not to have a permit, but another to not do it to code... Do what you have to do in an emergency, but don't plan a solution this way.

lakeside53
11-30-2012, 01:58 AM
I have my generator set up in a container which I use for a small shop and storage purposes. I wired a sub-panel into the container and installed a 30 amp breaker which feeds a 3-prong male receptacle. The sub-panel in the container is fed from the main power panel which means it's directly connected to all the power on the property. When the power goes out I throw the main breaker, isolating our system from the grid, open the container doors, start the generator and connect it to the plug with a cord, throw the breaker on the sub-panel and, voila!, I have power throughout our entire system. No need to run cords anywhere else. My generator is only a 6500 W so we do have to stagger the load but otherwise it works really well...

I don't know about Canada, but around here that is considered dangerous and most certainly illegal. Systems have to be fool proof with interlocked mains<> generator breakers or a physical transfer switch.

danlb
11-30-2012, 03:53 AM
The only thing wrong with the OP's plan (putting a pigtail with plug and socket on the heater) might be that code requires a hardwired connection for some reason or another.

I've considered doing the same for my AC, since it is fed directly from my meter (not the main panel) , and the generator transfer switch is between the meter and the main panel. There was no EASY way to redirect the AC to the circuit coming off the transfer switch.

Dan

Abner
11-30-2012, 07:43 AM
The reason for the DPDT switches is to make it physically impossible to back feed power into the grid. The key words are physically impossible. Your ability to connect and disconnect it correctly is not even considered nor will it be in any code book that I'm aware of. Keep that in mind- physically impossible will be the minimum standard.

Small loads like your boiler could be run off a pig tail by using a DPDT electric relay. I have my pump set up this way.

I agree with using the generator panel or a transfer switch.

bruto
11-30-2012, 09:44 AM
I think some people are misreading the original post. The poster is not intending to backfeed the system, but, if I read correctly, to remove the heater entirely from the system by making it, like some other accessories, a plug-in item that he unplugs in emergencies and plugs into the generator. A bit messy and not optimal, but easy and safe. If the number of circuits allows it, a user installed transfer switch like the one proposed by Lakeside above would be much nicer.

Bill736
11-30-2012, 10:04 AM
The idea of using plugs on appliances to connect to a generator in an emergency is fine, and my power company is fine with it too. There's no backfeed into the power grid , and I use a ground rod next to my generator to achieve a true three wire circuit. As I understand the OP, however, the complication is also using existing boiler cutoff switches in the circuit. If those switches are in any way still connected to the normal house wiring, and there's no transfer panel to isolate the power grid, then yes, it could create a hazard. I don't fully understand how the boiler cutoff switches are wired, however. You might also wind up with a voltage in parts of your house that you weren't expecting. Perhaps you could install a remote cutoff switch that is only part of the plug-in emergency circuit, and is non-functional otherwise. In that case, using appropriate heavy gauge wire, and switch, that can carry the full boiler current for the required distance is important.

Rosco-P
11-30-2012, 10:09 AM
I think some people are misreading the original post. The poster is not intending to backfeed the system, but, if I read correctly, to remove the heater entirely from the system by making it, like some other accessories, a plug-in item that he unplugs in emergencies and plugs into the generator. A bit messy and not optimal, but easy and safe. If the number of circuits allows it, a user installed transfer switch like the one proposed by Lakeside above would be much nicer.

Still a bad idea and any electrical inspector or electrician would probably have an issue with it. The storm has passed, install a transfer switch or transfer panel before the next one hits and be done with it.

gellfex
11-30-2012, 11:17 AM
The idea of using plugs on appliances to connect to a generator in an emergency is fine, and my power company is fine with it too. There's no backfeed into the power grid , and I use a ground rod next to my generator to achieve a true three wire circuit. As I understand the OP, however, the complication is also using existing boiler cutoff switches in the circuit. If those switches are in any way still connected to the normal house wiring, and there's no transfer panel to isolate the power grid, then yes, it could create a hazard. I don't fully understand how the boiler cutoff switches are wired, however. You might also wind up with a voltage in parts of your house that you weren't expecting. Perhaps you could install a remote cutoff switch that is only part of the plug-in emergency circuit, and is non-functional otherwise. In that case, using appropriate heavy gauge wire, and switch, that can carry the full boiler current for the required distance is important.

You and Bruto are correct about what I'm saying. The safety switch circuit has no connection with the house wiring, it's simply a loop off the boiler. A transfer panel would be an huge PITA, it's 60' from genny to panel, and I feel I don't really need it. Running a few cords to the kitchen and the boiler is no problem for me, we've have very few real blackouts in 15 years. We didn't even lose power in the big one where half the Northeast was out. They showed shots on TV of the whole west bank of the Hudson opposite Manhattan and our neighborhood was the only one lit! I understand the backfeeding issue and and at no time have proposed it.

danlb
11-30-2012, 01:58 PM
Just as a point of discussion:

There are several kinds of transfer switches. Some are installed next to your main panel and you wire individual circuits to it. Other switches go in line between the power meter and the main panel, and power the whole house from the generator.

Mine is the second style. It's a two foot tall box, with the incoming at the bottom and the outgoing at the top. It would not have required any extra wire if it were not for the fact that we have a requirement that it be mounted below a certain height.

Adding the whole house switch was a 1.5 hour endeavor.

My biggest problem is that I now need to find a way to vent the exhaust away from the area where I'd like to run the genny. The fumes permeate the garage if I run it in the space between the houses.


Dan