Connecting Generator To Transfer Switch Inlet - Electrical - DIY Chatroom Home Improvement Forum

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Old 12-18-2009, 07:37 PM   #1
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Connecting generator to transfer switch inlet

What I have:
1) 7500 Manual Transfer Switch which has a 4 prong male (NEMA 14-30) power inlet.
2) 4000W generator with 2 x 120v 15a outlets and 2 x 240v 15A outlets
3) NEMA 14-30 Female connector
4) 240v 20 amp male plug
5) 25 ft of 10/3 with ground (red, black, white, bare copper) outdoor cable.

I need to make a cable to connect the generator's power outlet to my transfer switch's power inlet.

Should I wire up the 14-30 using all four wires (correct color for each prong of course) and then wire the ground and white (neutral) to the ground prong on the generator side plug. Then wire black to one hot prong (slotted prong) and then wire the red to the other hot prong (slotted prong) ?

(then of course I would not use the 2 x 120v plugs or the second 240v plug)

What is the best way to go about this ?



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Old 12-19-2009, 07:42 AM   #2
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you have the right idea. The two 120V outlets are not used.


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Old 12-19-2009, 08:09 AM   #3
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You are attempting to use a 30 Amp input on your house with a 15 Amp output on your generator.

Also, it would appear that your generator is not set-up for dual 120/240 simultaneous output, as it does not have a 4-wire outlet present?

You should consider getting the proper sized generator to match your transfer switch inputs.

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Old 12-19-2009, 05:16 PM   #4
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Yea, Its a smaller generator. It was free (from an Uncle). I figured with it being smaller than the transfer switch it wouldn't mess up anything as long as i didn't overload the generator. I would only be able to run say the furnace (gas - just need electricity for ignition and fan), fridge, and a light and/or laptop. I have been watching for a bigger generator but nothing cheap has come up (which has the 14-30 connector on the generator side). The house when I bought it was already pre-wired with the transfer switch (otherwise I would of had it wired to match my generator). I am trying to avoid running extension cords and also like the idea that I would (for the sake of argument) spend the day in room 1 and then at night i could cut off the generator breaker for room 1 and cut on the breaker for room 2 (and then the bedroom would have everything working).

I have done some more research since posting my initial question.
This is one diagram that I found (would that just use the bonded ground/neutral wires in the transfer switch [assuming its bonded there like it is in the main panel] rather than providing the bond at the power inlet) ?

(direct link to image:

Would that work ok to just route a couple of items through the transfer switch and out to the generator ?
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