# 3 Prong Twist Lock Generator on a 4 Prong Transfer Switch



## gallantus (Nov 28, 2012)

I have a Ridgid 3600 Watt generator that uses NEMA L5 30AMP (the generator does not produce 240v only 120v). I chose this generator because it is sufficient for emergency power during hurricanes and it's not a gas guzzler as the long lines at gas stations during Hurricane Sandy convinced me on a less powerful generator. I plan to upgrade to a more powerful generator (capable of 240v) using NEMA L14 when my house gets natural gas; however I want to install a transfer switch that uses NEMA L14 30AMP right now so I don’t have to swap out the transfer switch when I upgrade my generator.

Can I do the following?

I will use a L5 inlet box, using a 10/3 wire connecting the L5 inlet’s ground to the transfer switch’s ground, L5 inlet’s neutral to the transfer switch’s neutral and the L5 inlet’s hot to one of the two hot in the transfer switch. Leaving the other transfer switch’s hot leg connected to nothing.

I will then switch out all double pole breakers on the transfer switch to single pole (I don’t need 240v at this point in time). Also, it is likely that half of the breakers on the transfer switch are tied to the unconnected hot leg, which means half of the breakers on the transfer switch will not have power (that is also ok for now and these breakers without power will not be wired up anyway).

I will then wire the transfer switch to the service panel according to the manufacturer’s specifications and instructions.

I now can start up the generator and flip the transfer switch to use the generator power and the net result would be: I will not get 240v two pole power and half of the breakers on the transfer switch will not have power.

In the future, when I upgrade to a more powerful generator that can put out 240v, I simply replace the L5 inlet with a L14 inlet and use a 10/4 wire to connect to the transfer switch.

Does anyone see any issues with this setup?


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## QuickRick (Sep 14, 2012)

Gallantus, 

Actually, to answer you quickly.....don't see why it won't work. 

The part of your equation that confuses me is how you will enter your L14 in-box? Usually, a 120 volt cord is only rated up to 20 amps tops. I suppose that you could buy an L14-30P cord and replace the gen side cord end with a male 20 amp 120 volt cord cap. 

You seem to grasp what your compromises will be, and certainly your cord wiring is sufficient.

Once you have a new larger generator, replace the gen side cord cap with another L14-30P male end. 

Note: don't make any assumpttions about the generator but check to make sure your generator uses a L14-30P or L14-20P cord. Ask me why I say this!

QR


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## Apple206 (Jan 28, 2015)

Good find. Thanks for sharing.


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