Generator: 2 phase connector to single phase?


Old 06-12-06, 12:13 PM
Thread Starter
Join Date: Jun 2006
Posts: 6
Generator: 2 phase connector to single phase?

Hi all! Sorry if this has been asked before..

Last year we moved into a home down here in Florida with a system in place to allow some circuits in the house to be powered by a generator in the case of a power outtage. Wary, I had an electrician come out and inspect the system to make sure no power company linesmen would be zapped by my generator if I were using the system.

The system looked good, so during the recent hurricane-preparedness sale tax waive here in Florida, I bought a generator. Unfortunatly, I misread the box and now my generator has a different connector than my 'house' takes. I'm hoping someone might be able to answer if I can safely wire an adaptor. I'm pretty handy but I just want to make sure I'm not breaking any 'rules'.

The house subpanel is wired to a cable with a three prong twist-lock connector that I believe is 125V/30A (probably an L5-30). On the generator, the plug takes a four prong 125/205V/30A L14-30.

So the question is, can I go to home depot and build a connector that converts the single/dual phase 4 prong L14-30 to the single phase L5-30. Perhaps one of the prongs remains unconnected?

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Old 06-12-06, 12:15 PM
Thread Starter
Join Date: Jun 2006
Posts: 6
Here are some photos of the connectors in question

The house connector (L5-20 or L5-30?)

The generator connector (L14-30)
Old 06-12-06, 01:00 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Please verify the type of connector on the end of your house cable. It should say on the connector what it is. Also, look where the other ends hook up.

I would be surprised if it really is on,y a 125 volt connection.

If so, you would want to use a different output on your generator. You would want to use a 125 volt output instead of a 240 volt output. If your generator has no 125 volt output then you are out of luck.

Without all the details it's hard to tell you if you would be better off getting a different generator or modifying the connection at your panel.
Old 06-12-06, 04:53 PM
Thread Starter
Join Date: Jun 2006
Posts: 6
Ok, the thread title is wrong. There's no 2 phase involved.

I've posted pictures of the connectors. The one from the house does not specifically say what NEMA type it is, but it does say 20A 250V, so I'm going to guess and say L6-20 since it's only 3 conductors. Doesn't that rule out 240?

The generator can output at either 120 or 240 through the L14-30. It clearly says 125/250 on the generator. The manual says : "Connect a 4-wire cord set rated for 250Volts AC at 30A. You can use the same 4-wire cord if you plan to run a 120 volt load. This recepticle powers 120/240 Volt AC, 60Hz, single phase loads requiring up to 5550 watts of pawer at 23.1A for 240 volts or two independent 120 volt loads at 23.1A each."

I've uploaded another picture of the manual drawing here.

Based on this drawing, can't I make a connector with one of the hot's not connected? Get a male L14-30, connect black to Y or X (hot), white to W (neutral), and Green to ground?
Old 06-12-06, 05:41 PM
Thread Starter
Join Date: Jun 2006
Posts: 6
Ok, I'm learning

I pulled out my Black & Decker guide to home wiring. I removed the panel and saw that the 3-conductor feed goes to a 2-pole breaker with the third wire connected to the neutral bar, which is wired to ground .

Anyway, I'm going to consult my electrician and get his opinion. I'll let you know what happens
Old 06-13-06, 08:33 PM
Join Date: Apr 2004
Location: Ontario Canada
Posts: 1,767
You need 4 wire cable with a 4 wire plug to mate with the generator.

The cord and plug you have is good for 240V loads only, as there is no neutral in it.

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