Wiring a Generator Independent of the house's wiring

I want to be able to get power into my house from a portable generator without the need of extension cords through open doors. I would like to install an external box that can accept at NEMA-type plug from the generator and then wire it to a couple of outlets inside the house that are independent of the rest of the house's electrical system. I won't need any transfer switch because the power from the generator will never travel on the main wires in the house.

My question: The box that accepts a NEMA plug has two hot (red and black) wires. Can I wire an outlet using the red wire and an another outlet using the black wire (with the white and ground wires common to both?)

Thanks.

Reply to
Carl
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yes you can, each red and black is 120v with white wire the common neutral.

how are you planning on powering furnace etc?

Reply to
hallerb

Thanks. I was pretty sure that's how it worked, but I couldn't find any website that talked about wiring it in this way.

The furnace will have to remain off during a power failure. If I want to get that fancy, I will get an electrician to hook up a transfer switch. I'm just trying to power the refrigerator, TV, some lights and a fan without having an open door cluttered with extension cords.

Carl

Reply to
Carl

There are better options than a true transfer switch available today for small generators. A true transfer switch is needed for large loads, but if you only have a small generator and have to do load management anyway there is no need for a transfer switch.

There are a number of small generator sub panels in the ~$200 price range that allow you to move 6-10 circuits that require backup to this new sub panel and each one essentially has a little transfer switch.

An even cheaper option that can be used for large generators as well as small ones is an interlock kit for your main panel. I just did a full panel replacement with a Square D QO panel and I installed a ~$30 interlock kit from Square D that interlocks the main breaker (200A in this case) with another 2 pole breaker (any size up to 125A) in panel position 2/4.

I have a 20A breaker as the back feed breaker currently since I'm only connecting a 5 kW generator, but if I switch to a larger generator I just change that back feed breaker to a larger size. You could even use an oversized breaker there if you wanted since it is really only doing switching duty, the over current protection is provided by the breakers on the generator itself.

This interlock kit is a much cheaper solution than a full transfer switch or even one of the generator sub panels. Since it's produced by the manufacturer of the panel it's a quality, approved option. Square D makes the interlock kits for their Homeline panels as well and I expect a few other manufacturers have similar options.

Pete C.

Reply to
Pete C.

Price out your exterior box, socket plugs,, cable to the gen. Now look at a Generac transfer switch kit, for 300$ you get everything , a pre wired 6 circuit panel with 2 watt meters, exterior box, extra sockets, plugs , cable. It is cheaper buying the kit, easy to install and you can power everything you need.

Reply to
m Ransley

I think you miss the point of the Square D interlock kit. The little generator sub panels only handle what circuits you relocate to that sub panel, the $30 interlock kit takes the place of a full transfer switch for generators supplying up to 125A. Since it provides power to the entire panel it also lets you power any circuit you need and do load management as required.

Pete C.

Reply to
Pete C.

Does the sqare d have watt meters, he did say portable gen, it would be to easy to overload the gen without a way to monitor it. I never looked into square d, I just put in the Generac kit since it was complete and pre wired .

Reply to
m Ransley

The Square D kit is nothing more than an approved interlock plate that only allows one of the two (main or back feed) breaker to be on at the same time, and a retainer bracket that prevents the back feed breaker from being inadvertently removed from the panel. There are no meters, inlet connectors, etc. The kit I used is a QOCGK2 if you want to see it on the Square D site, it's very different from the little generator sub panels.

As noted this is about a $30 kit that can take the place of a $200+ full

125A transfer switch. Even adding the cost of the back feed breaker and inlet box for a small generator it would total perhaps $100.

Overloading a small generator isn't much of a concern since the generator will have it's own circuit breakers and it will just pop them or stall the engine if you switch in too big a load like a central A/C compressor.

The interlock kit is a particularly good option for those who are comfortable doing load management, or in cases where a generator large enough to handle most everything is being installed.

Pete C.

Reply to
Pete C.

This is actually a cheap, simple, safe,and approved method of transfer. I've only seen it made by Square D for the QO series

Reply to
RBM

They also make it for their Homeline series panels.

Pete C.

Reply to
Pete C.

Pete C.

Any chance you could post the link to that on the Square D site? As an electrician myself, I'd like more info. This sounds perfect for some of my customers.

Thanks,

Glen

Reply to
Glen

The link to the new product announcement that covers the four versions of the interlock kit:

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Pete C.

Reply to
Pete C.

Thanks Pete,

This is quite a system. Effective, Simple, Inexpensive and Safe.

Thanks Again.

Glen

Reply to
Glen

AWESOME SYSTEM! Since we will replacing our main panel this decides the one we want..........

simple cheap flexible and safe

Reply to
hallerb

I've been Googling around looking for less expensive transfer panels/switches/relays etc and also found this puppy. It's great to see someone already using it. I hate to have to replace my entire load center but even so it's still cheaper and more flexible than anything else I've found.

The upside is it also gets me a main circuit cut-off inside the house that the contractor crap doesn't have.

One question though, maybe two ;-), where did you get the interlock? No one seems to have it and Square-D doesn't sell direct.

And a general question directed at anybody (who knows) - there wouldn't be a problem installing another set of mains breakers in series with the the main service breakers outside by the meter, would there?

Oh, and a third - does the inside breaker have to have the same rating as the outside one (150Amp?) There is a great SquareD value pack I'd like to use but it has a 200 Amp main breaker.

Thanks.

Pete C. wrote:

Reply to
swattsup

The inside Main can be larger than the outside main as the conductors are protected by the 150 amp . The inside would essentially just serve as a disconnect. Call electrical supply houses that are Square D distributors for the interlock

Reply to
RBM

swattsup wrote: > Pete C. wrote: >> RBM wrote: >>> This is actually a cheap, simple, safe,and approved method of transfer. I've >>> only seen it made by Square D for the QO series >> They also make it for their Homeline series panels. >>

You can get the Interlock at any Square D stocking electrical supply house. I've even seen them at the box stores.

The only issue with the series main breaker arrangement is that both breakers must have an adequate withstand rating for the available fault current. The 150 ampere breaker is undoubtedly sized for the service entrance conductors so you can't eliminate it without changing out your service entry conductors.

No the breakers don't have to be the same amperage rating as long as the one at the meter is sized for the size of the service entry conductors.

Reply to
Tom Horne, Electrician

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