Home>Discussions>ELECTRICAL & LIGHTING>Correct Wire Gauge For Portable Generator
12 posts / 0 new
Last post
William
Correct Wire Gauge For Portable Generator

I am looking into buying a portable generator for emergencies. This Old House just had one on their show recently and I really like the idea. I'd like to place it outside in the back yard when I run it. I just measured it and it's around 30 -35 feet from where the transfer box will be mounted (the power inlet box will be in the back yard with the generator). HERE is the portable generator that I was interested in (also interested in any recommendations that you might have). I believe it's 30 amp unit.

What gauge wire do I need to run between the power inlet box (in the rear of the house) to the transfer box (30 - 35 feet away)?

jkirk
Re: Correct Wire Gauge For Portable Generator

it should say right in the info book with the generator or theyll know if you go to a dealer as opposed to big box store

William
Re: Correct Wire Gauge For Portable Generator

I downloaded the owners manual for the portable generator, and also the install guide for the transfer box / power inlet box and the only gauge they talked about was "AWG #10 minimum". Don't I have to figure in how long the wire is going to be run? I would have thought that for 35 feet it would have been minimum AWG #6 or bigger. I just don't want to buy wire and then find out it was too small a gauge....

JLMCDANIEL
Re: Correct Wire Gauge For Portable Generator

Generally you don't have to up size wiring unless it is excess of 100 feet one way. I would suggest you look at a http://www.reliancecontrols.com/Products.aspx?pl= I would suggest a larger transfer switch than is needed for the generator, that way you have additional circuits that you can switch on and off as needed.

Jack

William
Re: Correct Wire Gauge For Portable Generator
JLMCDANIEL wrote:

I would suggest a larger transfer switch than is needed for the generator, that way you have additional circuits that you can switch on and off as needed.

Larger in which way? Larger as in more circuits, or larger as in more amperage?

The transfer box handles 10 circuits, which is the largest Reliance makes. I could get a 16 circuit from Generac, but because of the way it installs I would also have to buy an additional sub-panel box.

JLMCDANIEL
Re: Correct Wire Gauge For Portable Generator

Actually you can get up to 36 circuits. If you get one rated greater than the generator amperage it gives you the option of switching circuits as needed. It took less than a hour to install the one I have. It came with everything needed except the cable from the switch to the generator connection box. I wish I had gotten the next size larger so I could switch off the well pump and switch on the water heater once pressure was up.

Jack

William
Re: Correct Wire Gauge For Portable Generator
JLMCDANIEL wrote:

Actually you can get up to 36 circuits.

From which manufacture(s)? I only saw up to 10 circuits from the link you posted above. Also, they make a power inlet box that has a circuit breaker added to the connector. Should I be considering this or is it over kill, considering the portable generator already has circuit breakers? Thanks.

JLMCDANIEL
Re: Correct Wire Gauge For Portable Generator

For that size Gen I would recommend you get this http://www.reliancecontrols.com/ProductDetail.aspx?30310A It has more than enough circuits for emergency use. 8 120 volt circuits and 2 240 volt circuits plus power meters so you can watch and make sure you don't overload. They ave other units that go up to 36 circuits but it would be a waste. You can get an idea of prices here http://www.northerntool.com/shop/tools/NTESearch?Ntt=transfer+switch&Search.x=39&Search.y=7
It would be item 31410CRK

Jack

JLMCDANIEL
Re: Correct Wire Gauge For Portable Generator

And a little cheaper from Homedepot

Jack

William
Re: Correct Wire Gauge For Portable Generator

THANKS Jack!

So do you think it would be OK to run AWG #10 for 35 feet from the Inlet Box to the Transfer Switch, or should I go #8 or #6?

JLMCDANIEL
Re: Correct Wire Gauge For Portable Generator

10 is fine. It will handle all that that Gen will output.

Jack

Pages

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.