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broadbill 04-22-2009 08:56 AM

Generator Cord and Inlet box 20A to 30A
Hi all;

Quick question regarding a generator cord and inlet box I inherited from my Father when he updated his generator transfer box setup.

The generator cord and inlet box are 20A. However, the generator I bought only has a 30A, 240V outlet.

If I wanted to use the inherited cord and inlet box, can I change the 20A plugs on the cord and inlet box to 30A? If I'm not mistaken, the big issue would be if the cord had the correct gauge wire in it to carry 30A. (Just for the sake of argument, please assume that I'll be able to get the plugs removed from the cord and inlet box.)

Thanks in Advance!

kok328 04-22-2009 12:20 PM

Yes, you are understanding correctly however, if the generator it was hooked up to was 120V 20A then the cord will be fine for 240V w/30A plug ends. I say this because my generator only has one duplex 120V outlet on it, instead of one 240V outlet.

broadbill 04-22-2009 01:14 PM

The generator I have has 4 120V outlets and a 120/240V 30A outlet.

kok328 04-22-2009 02:17 PM

The answer depends on how you plan on using the generator outlets to supply the home.
Are you attempting to power both phases in the breaker box or just a few select circuits?
What is the AWG of the cord that you want to use?
How many conductors are in the cord that you want to use?

speedy petey 04-22-2009 08:09 PM

For this purpose you can have a 30A plug and a 20A female cap on the cord. The cord should be 30A rated.

How are you transferring the load?

broadbill 04-23-2009 07:49 AM

Thanks for everyone's input.

My plan for transferring the load into the circuit box is to have a manual transfer box at my circuit breaker panels with a line running from the transfer box out to the inlet box outside of the house. I would then use the cord to run from the inlet box to the generator.

As I said, I need to switch the plugs on the cord and in the inlet box so that its compatible with the 240V outlet on my generator.

The cord is 12/ that sufficient gauge for 30A?

Speedy Petey: Are you saying that I would only have to change the male end of the cord but can leave the female end (the end that goes into the inlet box) as 20A? How would that work with more than 20A of load being pulled from the house?

Hope this helps...thanks again to everyone for their help!

travelover 04-23-2009 08:45 AM

For 30 amp service, you need everything from the plug on the generator to the service box to be rated for 30 amps or more. That means at least 10 gauge wire. Most setups now use 4 wires, which includes a separate ground wire.

kok328 04-23-2009 09:00 AM

Thanks for the information.
Based on what you have told me, the 12/3 cord will be sufficient for a 240V/30A circuit or a 120V/20A circuit.

electrical contractor 05-04-2009 12:02 AM

12/3 is not suffiecient for 30A 12/3 is only good for 20A. So long story short, no your inherited Cord is not suffiecient. If you can replace the receptacle in the Inlet box, it could be reused, however by the time you do this you may be better off just buying a new one.

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