Making an extension cord for a generator?

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  #1  
Old 06-18-05, 07:03 PM
Rainbow
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Making an extension cord for a generator?

I have a generator that has a "120/240 Volt AC, 20 Amp Locking Receptacle" tha came with a NEMA L14-20 Plug (Image from Generator manual)

I only plan on using it for 120 volts, is there a problem in using 10/3 wire to create the extension cord or do I have to use 10/4 wire? The other end will be a NEMA 5-20R.

If I do have to use 10/4 wire what do I do with the other hot wire? I only need a hot, neutral and ground for the NEMA 5-20R.

Thanks;

Steve
 
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  #2  
Old 06-18-05, 07:14 PM
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Steve,

Basically, on your schematic it shows they polars between the two hots as 120 so if you choose to only use one hot in this cord you are fine to do so from what I see.

Most will use a cord like SJ Cord or simular to make this up.....just make up the cord leaving one of the hots off and just to be safe put some tape over the remaining screw inside the NEMA L-14 Plug and you should be fine.

So in closing.......the 10/3 SJ or simular should be fine again just leave one screw setting in the connector empty. Now don't hold me to SJ fella's for an extention cord.....I am on the road right now and do not have my code book with me...but DO NOT use NM Cable for this....but I am sure you know this already.
 
  #3  
Old 06-18-05, 07:24 PM
Rainbow
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Thank you. This is a semi-related question.

Do they make a receptacle for 120V 30 amp, From what I can see from the NEMA coding it would be a NEMA 5-30R , but the configuration seems to be different will this accept a standard straight blade plug?

I'm also guessing it would not be safe to use the 5-20R for another extension cord from a different receptacle on the generator that is a "120 Volt 30 Amp Locking Receptacle".

Thanks again;

Steve
 
  #4  
Old 06-19-05, 05:50 AM
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Steve,

I am sure they make a female end plug for every male attachment plug they make, Just a matter of finding it but again most places that carry the one will have the other.

On the question of can you use the 20R female with the other end being a 30R.....no.....if the circuit is for 30A you need to use a plug rated for such as that would be the NEMA intent of the actual rating and their is a rating for a reason....and most of these have been safety tested as well.

Same principle in that you do not want to put a 30A breaker on a 12 AWG -20A Rated Wire........just not right not to mention just not LEGAL...


Ok......I dont want someone saying..wait ElectricalMan...what about in motor circuits which in cases allow the breaker to be larger rated than the wire....blah...blah...lets not go their people...thats a whole different deal..lol......those are special allowances by the code and do not pertain to this situation....

In closing...Steve you are better off using the RIGHT plug at the right amp rating and just not using one of the HOT connections than going down in size to a 20A to meet the need...because the breaker rating on that circuit in THAT generator is 30A.....you need to size for it.
 
  #5  
Old 06-19-05, 06:07 AM
Rainbow
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Thanks again.

I was just clarifiying somethings I already knew, but just wanted confirmation.

The first question about the 240/120 volt receptacle is a 20 amp outlet so the 20 amp end that I have will be fine. I now just need to find a 30 amp outlet for the other receptacle on the generator, but I'll find that. Like you said it is out there somewhere.

Thanks again for all the helpm you guys are great.

Happy fathers day to all that it applies to.

Steve
 
  #6  
Old 06-19-05, 06:37 AM
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Why are you concerned with trying to pull 120 from both the 240 volt 20 amp receptacle and the 120 volt 30 amp receptacle? You most likely cannot use both of these at the same time (on most generators it's one or the other).

On my generator, I wired a short extension setup that gives me two runs of 120 volts 20 amp from the 240 receptacle.
 
  #7  
Old 06-19-05, 11:57 AM
oldson
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From oldson

Rainbow, I asked about the same question earlier last week on how to get 120 v from the 240 v receptacle on my generator, but unfortunately wasn't as clear as you in my request. Hope you don't mind me "piggybacking" on your thread.

For Racraft: Can you give me the particulars on how you wired your extension cord to get two 120 v outlets from yout 120/240 v receptical ? That's what I really needto know.

Thanks, oldson
 
  #8  
Old 06-19-05, 12:28 PM
Rainbow
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Originally Posted by racraft
Why are you concerned with trying to pull 120 from both the 240 volt 20 amp receptacle and the 120 volt 30 amp receptacle? You most likely cannot use both of these at the same time (on most generators it's one or the other).

On my generator, I wired a short extension setup that gives me two runs of 120 volts 20 amp from the 240 receptacle.
Racraft:

I've read the manual pretty thoroughly and there is nothing that says I can't use the 120/240 20amp receptacle and the 120 30 amp receptacle at the same time.

These are 2 separate outlets, in addition there is a 120 Volt 15amp Duplex outlet. Each have their own circuit breaker.

I was thinking about pulling 2 120 circuits off of the 240 Volt receptacle, but was not 100% sure how to do it.

I'm guessing that each outlet would share the ground & neutral and then get 1 leg of the 120. Is this correct?

Thanks.

Steve
 
  #9  
Old 06-19-05, 02:05 PM
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Steve, your generator can supply a certain amount of electricity, measured in watts. You cannot exceed that amount of electricity. Yes, you can use all of the receptacles on the generator at the same time. But you cannot exceed the amount of power that the generator can put out. Because of this, there is no reason to use all of the receptacles on the generator. Just use the 240 volt receptacle and connect all your loads there.


Your 240 volt receptacle has two hot wires, a neutral and a ground. For my generator, I wires a simply quad receptacle box (two duplex 20 amp receptacles). I have a short piece of four conductor cable that plugs into the generator. At the receptacle box, each hot wires goes to one duplex receptacle. The neutral goes to each receptacle, as does the ground. This is a multi wire circuit.
 
  #10  
Old 06-19-05, 02:22 PM
Rainbow
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racraft;

Thanks for the advise. I know I can exceeed the 4000 running watts my generator can supply and I was going to use all the receptacles to power what I would need before I considered pulling 2 legs off the 240 seperately.

Again thanks for the advise.

Steve
 
  #11  
Old 06-19-05, 03:18 PM
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Steve,

Good point by RAC....no since wasting that one line when you can use it....I think RAC hit it right on the nose in that you would not need to wire it any different and go ahead and use the 4 wire and wire the plug up as it should be...Just bring it to a 4 x 4 Square QUAD and have a multi-wire circuit in it...meaning as RAC said...share the Neutrals and ground and seperate the (2) hots to seperate recepts and get two circuits out of it...

Great post RAC........my 3,500 W generator does not offer 240V but if it did....I would do that...theheheheheh
 
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