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I have been spinning my wheels reading on this trying to figure out what to do.

I have a 5000W Portal generator that is NG bonded The generator has a 250V output with a L6-20R connector.

I have a Square D generator interlock installed by an licensed electrician The power inlet on my house is an L14-30R.

I bought a generator cable but both ends are L14-30 (4 prong). I bought a L6-20P connector and plan on installing this on Plug side of the generator cable (i'd cut off the 4 prong).

The question is how I wire the new L6-20P on the cable: The L14-30R has X,Y,Neutral and a Ground. The L6-20P has X,Y and G.

When I put the L6-20P on the end of the generator cable, should I hook G of L6-20P up to G of L14-30R? This would give me two NG points in the system since the generator is NG bound.

The other option is to not connect the G to anything and just hook up X/Y?

Thanks for any help,

- Mike

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    Ok, so you're really, really gonna need that neutral, otherwise you will have an "open neutral" situation and your appliances will blow up. The 6-20 lacks a neutral. Now you need to consult with the generator manufacturer and find out whether they support what you need: split-phase power, and how to cable that if they do. – Harper - Reinstate Monica Sep 7 '17 at 18:20
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    Look at the seller, "sold by and ships from <not Amazon>", that is the Amazon Marketplace, which is akin to eBay or AliExpress. There, somebody will sell you anything. It's the wild west. I'm not saying it can't be done, I'm saying only the manufacturer can say whether or how they support this. If it's a no-name generator, you might have to take it apart and see how it's wired, and add that to your question. – Harper - Reinstate Monica Sep 7 '17 at 19:38
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    Apparently they make several models which meet that description, and the one I spot-checked had an L14-20 and stated vey plainly that it supported 120/240 right on page 2 of the manual. If your manual says 120/240, then this can be done. powermate.com/productmanuals.php?cat_id=3 Otherwise we'd need to see how the receptacles (120 and 240) are wired on the back. – Harper - Reinstate Monica Sep 7 '17 at 20:21
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    Its sounds like you're fine then, connect those 2 neutrals (both) to both the neutral on the NEMA 14-20 and the neutral on the NEMA 5, then tie generator chassis to all the ground pins, then finally tie neutral to ground somewhere Don't let any neutrals be disconnected or you'll have lost neutral problems, your two 120V sides will total 240 but they won't be 120 each! – Harper - Reinstate Monica Sep 7 '17 at 20:57
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    Yes, since it's already so on the 120V plug. – Harper - Reinstate Monica Sep 7 '17 at 21:19
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Forgot to come back here since there was no answer posted. Appreciate @Harper's help, I wish they would have put an answer so I could accept!

So I ended up buying an L14-30R and replacing the L6-20R in the generator. I wired neutral over to the 240V and wired up the two hots to it. I wired ground over to one of the 120V that had ground on it but I REMOVED the jumper from ground to neutral.

Since I only have a interlock and a inlet plug for the house, neutral is NOT switched over to the generator. If you have a proper transfer switch neutral MIGHT be switched to the generator. Since neutral was not switched, I'm using the house's NG bond and therefore I want neutral to float in the generator. If you do this, you should label the generator as Neutral floating in case you sell it or need reminding.

Everything worked well when I was running on generator power for 3 or 4 days after an ice storm.

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