Home circuit breaker box question

Because some devices have 220 fed to them so you need to have both breakers adjacent. That's normal. Either get a split 220 generator properly installed or just unplug things and run them from the generator via extension cords.

Hard to say why. Maybe it has a solid state control? Remote?

If the generator delivers good 60 cycle power it should work fine.

Everything you suggest is nasty and could kill someone. Get a proper isolater switch from Home Depot etc. If you back feed power up the lines by forgetting something, you could kill a lineman or someone else one day.

N

NononononoNO! NEVER run emergency power that way!

For starters, circuit breakers don't work reliably in reverse. That's why they have a 'Line' and 'Load' side. If you get an overload while running your generator into an outlet, the breaker may not trip. This could easily start a fire, damage your generator, and cause your home insurance carrier not to honor claims related to any damage from such activity.

The other issue, and the reason you were missing power to some rooms, is that modern residential power lines are split-phase. You get two 'hots' which, between them, carry 220V, and a neutral line. The two hot leads are usually split inside the breaker box to avoid loading one side too heavily. Your generator was likely only providing power to one of the hots.

Another factor of Why You Don't Want To Do It This Way: It's in direct violation of the National Electrical Code, and probably local codes as well. If you get caught running things that way, you could have many more worries than just the risk of overload and a few dead rooms.

The ONLY way to correctly run emergency power, so that there is minimal risk to you and any power company folk who happen to be working on the lines, is to install a proper generator transfer switch. Such are readily available from home-improvement stores (I prefer Lowe's, personally) or industrial electric suppliers such as Platt Electric or Graybar.

They're not particularly difficult to install, but not all states or counties allow the homeowner to do electrical work, and you will have to have the completed installation inspected no matter what (if you expect your homeowner's insurance company to continue to honor your policy).

The thing to do is check with your local government's electrical or home inspection office. They will tell you if (a), you as the homeowner are allowed to do electrical work, and (b), what permit(s) you'll need to get a transfer switch going.

You may be better off leaving the job to a professional electrician.

And no, BTW. It would not be at all safe, for you or any power- line workers, to "jumper" anything in the box. Get a transfer switch. Period.

Happy tweaking.

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you need a generator with 2 phase out . that is 2 120 volt outs that are out of phase with a common/neutral. commercial power in the US for residents normally have a center tapped transformer that will give you 120 from outer tap to center and if you need 220 for dryer, the 2 outer only are used ! because they are out of phase from each other bye 180 degrees, you can get double your voltage. in houses, its common to split up the load and try to equally load the 2 120 lines coming in. this means you should have a generate that outputs 2 120 lines that are out of phase.

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Get a generator transfer switch, it's the only safe and legal way to do it and you'll save yourself a lot of headaches. You can get them at any hardware store, they have a number of switches that let you select individual circuits between line and generator.

Circuit breakers will work just fine in reverse, the current is AC so it's reversing rapidly anyway but either way it makes no difference at all. There's plenty of other reasons not to do what he's contemplating though.

}(snip) }For starters, circuit breakers don't work reliably in reverse.

Explain please...what's inside a curcuit breaker that needs to have the AC connected to the LINE to not malfunction?

Stan.

Firstly, I would have thought it would be mandatory for the main utility supply to have a supply disconnect switch at the entry point to the main distribution box, and it would not be something you could elect to add at your own discretion.

Also, you didn't say whether the disconnect switch allows selection of either the mains or generator supply or whether this is performed safely by following a defined manual sequence for change-over.

The main supply disconnect switch usually consists of make contacts only and this switch is either on or off. Assuming that only active and neutral are passing through the switch then it will consist of 2 make contacts.

In order to create a demarcation point for the house wiring and the new generator input socket you should follow the mains disconnect switch with a similarly rated switch which has double change-over contacts (break before make). One side of the contacts will connect to the active and neutral outputs from the main utility disconnect switch, while the other side will connect to the respective line and neutral pins on your generator input socket. The common side of the switch will connect to the house distribution circuit breakers and neutral link. The switch allows you to select either the main utility supply or the auxiliary generator supply without the possibility of accidentally connecting both the supplies together. It provides a fail-safe system to prevent such an occurrence, and may be mandatory.

You may be able to get away with substituting the make only main supply disconnect switch with the change-over switch, but then there will be no clear demarcation point between the main utility supply side of the wiring and the auxiliary generator supply side.

Ross Herbert

- big snip -

Thanks to all who've replied so far ... given me quite a bit to think about.

FWIW, my circuit box was installed by a certified electrician .. I simply didn't feel competent to do something on that scale. They pulled my meter on the side of the house in order to install it.

The 4KW generator I have (by Coleman) has 2 AC outlets, which, when measured unloaded, provide 130 VAC. I haven't tried to measure across the 2 outlets to see if 260 VAC is available, but I suspect that I will find that is true.

I suppose I could wire up some kind of cross-over switch by the box on the side of the house next to my Central A/C compressor unit. That would be the logical place to bring in 220/240/260 vac.

I will continue to read your comments, and check at Home Depot or Lowe's for the switch many of you have described.

Cheers, Bill

I would never wire one backwards, however they should work either way. They are more subtle than most people know however.

N

Perhaps you didn't tell him all of what you had in mind. A good electrician would have explained the danger, and illegality, of installing your backup power this way.

My guess, and it's just a guess, is that you'll find that both outlets put out the same 130V. There should be a spec plate somewhere on your generator that gives its output voltage. If it doesn't mention something above 200 V somewhere, then you have a very straightforward

120V single phase generator.

This transfer switch, what you're calling a cross-over switch, needs to be inserted in the line between your meter and your breaker box. It's purpose is to make sure that there is no way that you can ever connect both the generator and the line to the house, or the generator to the line. It's for your safety, the safety of anyone working on a downed line in your service area, and the safety of your generator. It could also be wired up permanently with a cord which you could safely plug into your generator when the need arises. You don't EVER want to have a male plug that can be hot when unplugged.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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The transfer switch doesn't go between the meter and the panel, it wires into the panel and the individual circuits go between the breaker output and the hot wire to the circuit you wish to have backup power available to. They're metal boxes with a plug for the generator and a flex whip to wire into the panel, they start at around $120 for a small one.

Then let me rephrase:

The transfer switch goes into the line feeding whatever load you wish to provide emergency power to. In his case, he's asking to feed the whole box, which means that he needs one of the larger transfer switches and he needs to put it in the line between his meter and his service panel.

Of course he probably also needs a bigger generator, and one rated at

220V, but the box he is asking to power really isn't all that big, so I suspect that he just needs a 220V generator and a transfer switch rated to handle the total box power.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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