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Generac cord question: 240v twistloc to (2) 120v duplex outlets

Posted by ksnh (My Page) on
Sat, Apr 17, 10 at 13:13

Anyone ever hack off the two duplex outlets?

I am thinking that the 30 amp cord, with the two duplex outlets removed, and a female 30 amp twistloc added, would make a legit generator-to-house supply cord. The main cord is marked "STW 4/C 10AWG."

I figure that this means that the main wiring is 10/4 to the base of the duplex cluster and then split off to each outlet. If so, the 10/4 wiring could be accessed just before being tapped off to the individual duplexes, and connected to the new 240v female connector to restore full 30 amp capacity.

Has anyone ever done this, and can say for sure how the cord is internally wired?


Follow-Up Postings:

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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

I'm an Electrician, and you TOTALLY lost me.
If you are wanting to make 2 120 volt circuits out of 1 240/120 circuit, have you thought about branch curcuit overcurrent protection? at 30 amp for each line at 120 volt?,shared nuetral on flexable cord?


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

OK, after rereading, after sleep, Yes that should be fine.
I origanally thought you was going to add 2 recepticles to the end of a cord.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

Thanks for the reply. The last sentence in my original post ("Has anyone ever done this, and can say for sure how the cord is internally wired?") is my main question.

I know how to make a conventional generator-to-house supply cable; what I don't know is if the Generac cable uses 10/4 right up to the duplex cluster. If that is the case, then to cut off the duplex cluster would leave a male Twistloc to bare 10/4 cable, which would in turn need only a female Twistloc to make a complete supply cable.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

The Generac cable would have to be 10/4 all the way to the "duplex cluster" or there would not be two independant 120 volt circuits available at the duplex cluster.

One of the duplex outlets uses the RED lead of the 10/4 cable to provide 120 volts to that outlet. The other duplex outlet uses the BLACK lead to provide 120 volts to it. Both duplex outlets share the neutral WHITE lead found in the 10/4 cable along with sharing the GREEN grounding lead.

I assume that this duplex outlet cluster is all moulded in with the actual 10/4 supply cord and that's why you are unable to open it up to see what they did.

Don't sweat it. Cut it off and install the female twistloc.

Please tell me that you are smart enough to have installed a proper "Transfer Switch" in whatever building this generator is going to supply power to. Transfer switches PROTECT you, your loved ones and also the utility linemen who have to work on the power lines that have been damaged.

Keep this in mind. If the local utility sends 4800 volts down your street to supply 120/240 volts to your home from that transformer on the hydro pole or sitting on the hydro vault at the curb.... your generator can send 4800 volts right back down that street line and electrocute a lineman who just tested that downed wire moments ago.

Line transformers work both ways. They can either increase voltage or reduce voltage. Transfer switches are designed to TOTALLY ISOLATE your generator from the incoming power line and vice versa. Transfer switches are a MUST. Do not feed genny power into your electrical panel without a Transfer switch inbetween.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

Just for the record, those linemen are smarter than you
give them credit for. They don't touch those downed
wires until they are properly grounded. And they handle
them as if they were still hot. Also, they are
now called 'Line Mechanics',since there are now females
doing the work.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

I give them plenty of credit for their safety practices but it only takes a tiny slip-up caused by a momentary failure to follow procedure for a tragedy to happen. While I fully understand the thought behind what you wrote, nothing contained in your post should be considered to be an excuse for not using a transfer switch.

On another forum, a member was asking for for some advice about his generator. He thought it might have become damaged. WHY????

Simple. There was a storm. His power went out. He went to his panel and flipped off the main. He went to his garage and used his custom made double male end cable to connect his genny to his welder outlet in the garage so that it would backfeed his main panel. He started up the genny and left it running so his wife would have electricity while he was out.

His wife was monitoring the radio and learned that the power would be turned back on in a few minutes time. She went to the garage and turned off the generator. She then went back into the house and flipped the main breaker back on in the service panel. She then realized that she had NOT uplugged the generator and started to back to the garage when suddenly the power was restored.

By the time she reached the garage, smoke was now coming from the generator so she quickly unplugged it. I have yet to read an update as to what damage, if any, was suffered by the genny. Like I said... it only takes a brief second of inattention to create a dangerous situation. Had she not run back to the garage, the genny might have caught fire. Who's to say what may have transpired after that.

There's a right and wrong way to do many things. This is one of those things where doing it wrong can have many disasterous results.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

This why I hate these kinda posts, everyones an electrician, I will now say, CONTACT A LOCAL ELECTRICIAN.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

Where I live, most home electrical work can be done by a homeowner w/building inspector sign-off. I replaced the main entrance panel in my house using a Reliance 200 amp panel with interlock that permits toggling to generator only when the utility line has been disconnected. I worked with a licensed electrician to do the utility-to-panel connection, and both he and the building inspector signed off on the entire project. The wiring to the generator is overkill: 50 amp connectors and 8/4 wiring.

All I want to know is how Generac wires the Twistloc-to-duplex cord. I want to avoid cutting the cord and exposing some weirdness that will prevent what I want to do; for instance, if "10/4" as marked might actually mean "12/8" where each duplex pair might get its own separate wiring from the male Twistloc, but the combined current capacity would still allow the 10/4 marking.

Kompressor, you are on track to be the "Smokey the Bear" of generator safety. However, there was nothing about my post suggesting that I was one step away from barbecuing some fresh-faced young linesman with eight hungry kids and two more on the way. You could ask a one-sentence question about hookup method, and if the response involves "speaker wire" or something equally chilling, then you could cut and paste your "backfeeding" message.


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RE: Generac cord question: 240v twistloc to (2) 120v duplex outle

ksnh,
What you seem to dismiss is that what goes on in this thread is not a private conversation. There is no telling how many people will read this thread while it is current (no pun intended) or years from now when someone decides to drag it out of the archives.

So, when I post a reply to ANY thread, I do so on the basis that I'm talking to a huge room full of people with varying skill levels and not just to the person who asked the question.

Since you have worked with a licenced electrician on this project, I am now with Smokebuzz. Consult that person or contact Generac's technical department directly to get the answer you apparently are not receiving in this thread. I reside in Canada and the heaviest, standard duplex outlets are rated for 20 amps max. So, I can't tell you if Generac uses duplex outlets that are designed to accept #10 wire directly to them or not.

The chances of you finding someone on this forum who has cut one of the cords open and conducted an in-depth inspection to see how Generac did it, is remote at best.

I don't see what your concerns are but perhaps that's just me. If the cord itself is clearly marked 10/4 Type SJO or something similar and this message is repeated all along the wire, then I wouldn't sweat it. I'd just cut off the end with the duplex outlet arrangement on it, install the 4 pole twist-loc and be done with it.

IF that doesn't suit, then go to any electrical supply outlet and purchase a length of 10/4 cab tire along with the correct ends and make up your own connector cord.


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