Backfeed generator through dryer outlet?

[beerguzzler50]

Let me start by saying I know this is very dangerous and I don't plan on doing it (I have a new generator and new uninstalled transfer switch) so save your flames. I plan on installing my transfer switch when I get some time in the next month or two.

I read a post suggesting that in a power outage, you could flip your main breaker off to prevent anything going to the lines and killing a line worker, and use a suicide cord from your generator to you clothes dryer outlet (240 vac) and then your main panel would serve as your switch for what circuits are using the generator--and that this would power both 240 and 120 outlets.

As dangerous as this is, is this even possible?

[louie]

Yes, but not recommended because of the potential danger involved (both to the homeowner and to the line workers in the event someone forgets to turn off the main). You would be limited by the size of the breaker you are feeding through (in this case the clothes dryer), but it would make your whole panel live just as if it were being fed through the main.

[Jim & Lil]

I had asked this hypothetical question a few years ago and glad you mentioned the flames...LOL...Cause I sure got my fair share of those asking that question.. One thing that was constructive in my replies is that even with your main braker shut off, you may be still feeding power down the line via the neutral wire....another constructive reply was to also ask in alt.energy.homepower They are a very knowledgable group... Hope that was of some help.... Jim

[Me]

Yes, it is possible......BUT only a person with your special qualifications (beerguzzler50) should even THINK about doing it, let alone actually TRYING to do it....... I think the "I was drunk at the time" defense might actually work for you.

Me

[nicksanspam]

Sounds possible, and safe, unless you guzzle too much beer. You might hang a big tag on the generator that says "Turn off the main breaker!"

That seems a very unlikely hazard, since it requires 1) a grid power failure, and 2) a hot to neutral connection that doesn't blow your own breaker, and 3) a neutral wire that doesn't end up attached to ground somewhere outside your house.

Nick

[BobG]

Also, the line splicers ground the lines they're splicing. That will make your generator extremely unhappy for a few seconds should you forget to pull the main.

[JoeSixPack]

[zxcvbob]

I would do it in an emergency if there was an extended power outage, but I'd probably pull the electric meter first to make absolutely sure I wasn't backfeeding the power lines.

Yeah, I know about breaking the seal on the meter, but ya gotta do what ya gotta do if it's really an emergency.

-Bob

[JoeSixPack]

[Toller]

I've done it. Lots of other people have also. But there actually have been fatalities as a result of doing it.

I put in a transfer switch because it just made me uncomfortable.

[maradcliff]

I'd like an explanation of how you could feed power down line thru the neutral?

[JoeSixPack]

For the added piece of mind, a generator/main selector switch is a modest investment. Power failures can result in stress and confusion that make things like leaving the main breaker on a virtual certtainty at some point. Why take the chance to save a few bucks.

Unless I'm mistaken, some 240V outlets do not have the neutral wire connected to the mains. Only a ground wire, which is insufficient to power the 120V circuits. This would result in 240 service only in the house wiring, when feeding in from a generator.

[barry]

I'm surprised nobody's mentioned being sure to have (2) hot leads and neutral, so you can power 117v circuits.

I've done this sort of thing many times over the years, but via single

117v 15a or 20a branch circuit. Main opened first, ditto all breakers (which are accurately labelled as to which load). Of course circuit is chosen so as to power selected "phase" which luckily has covered the necessary loads. Then one breaker at a time on, and maybe rotated as necessary. (Refrigerator does not need power 100% of time, nor does furnace blower. Yada, yada.)

At a friend's house, opening main breaker one time, caused it to fail to close forever more. Which sped up replacement.

HTH, J

[nicksanspam]

I've heard that's never actually happened. Can you name one?

Nick

[Pete C.]

You are partially mistaken. Some older 240v outlets indeed do not have a neutral connection, however newer ones do (code change). Since the ground and neutral are required by code to be bonded at the service entrance panel you will get the same functionality even if you're feeding an older dryer outlet with no dedicated neutral i.e. using the ground as a neutral.

The ground on the circuit may be a gauge lighter wire than the main conductors which would limit your circuit capacity if you had a large generator (~7kw or larger), but most people doing a dryer outlet backfeed will have 5kw or smaller generators in which case even a reduced gauge ground on a dryer outlet has adequate capacity.

Additionally since not only are the ground and neutral requited by code to be bonded at the service entrance panel, there is also a required ground rod (or two) connection at the service entrance panel which makes it all but impossible to backfeed any power down the line if the main breaker is off. The additional grounding of the utility system neutral every few poles provides yet another level of protection.

The true risks are 1. Forgetting to shut off the main breaker, and 2. Forgetting the danger of the double-male "suicide" cord and proper connection / disconnection sequences.

Pete C.

[Toller]

A couple years ago I asked the same question. Someone came up with at least one example. It does seem unlikely; if your main breaker is closed, your genny should stall immediately when it tries to power the neighborhood. The only way you could kill a lineman is if YOUR line if down and he is fixing it, or if (and even this is a reach) you plugged in while he what handling a nearby line. Of course, even then he is supposed to be protected from live wires by insulation.

Still, a transfer switch avoids the embarrassing chance of continuing to run on generator after you have power back. I did that for an hour once before someone called me.

[Tony Wesley]

I've heard the moon is made of green cheese

[JoeSixPack]

If the neutral isn't properly grounded at the service tap, it is forced back up the line to the next good grounding point. Not a serious danger unless people or equipment are connected in parallel to this defacto circuit. I think it's possible that someone in an adjacent residence could be at risk of getting a shock by being connected to both a good ground and the ground terminal of an outlet, if the resistence to ground is greater at their junction box. An example might be having one hand on a water tap and the other on the metal case of an appliance with a 3-prong plug, and feeling a tingle of current that originated from your neighbor's generator.

[JoeSixPack]

Couldn't you wire in a light on the power main side to tell you when the power is back on?

[Solar Flare]

When they turn the power back on you can generate your own gasoline as your unit regenerates. This can be syphoned off for your car usage at a very cheap rate.