Nema L6-20

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vikkaraja

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Hello there, I am wiring up a 240VAC 2 wire 1 phase recepctle. I have 240VAC 3phase subpanel where I can install an additional circuit breaker to get this job done. I would like to just make sure that I am doing it correctly. On this subpanel there are 3Hot and 1 ground come in from the main panel. Between the phases I am getting 240VAC and from ground to any one of the leg it reads 240VAC also. Sould not I be reading 120VAC instead? Any help.

Thanks.
 
iwire

iwire

Moderator
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Location
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The readings are odd.

I think it may be posable you have an ungrounded Delta feeder to this panel and are reading capcitance coupling.

What type of meter are you using?

Is it posable the readings are more like this:

240 Line to Line

240 from 2 lines to ground

0 from the other line to ground
 
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jim dungar

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Location
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PE (Retired) - Power Systems
vikkaraja said:
Hello there, I am wiring up a 240VAC 2 wire 1 phase recepctle. I have 240VAC 3phase subpanel where I can install an additional circuit breaker to get this job done. I would like to just make sure that I am doing it correctly. On this subpanel there are 3Hot and 1 ground come in from the main panel. Between the phases I am getting 240VAC and from ground to any one of the leg it reads 240VAC also. Sould not I be reading 120VAC instead? Any help.

Thanks.
Click to expand...

No, you would get 120V from all L-G only if you were on a 208Y/120 system. If your system was a center tapped delta (240/120 3PH 4W) you would get 120V L-G on two legs and 208V L-G on the other leg.

As Bob said, it sounds like you have a 240V 3W-wire delta system.

Because your L-G voltage is 240V you cannot use a standard 120/240V 2-pole breaker, you will need to use one the more expensive one rated 240V only.
 
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vikkaraja

Member
yes, it is 3 wire Delta system. So there is no way I can use this panel for my need, I would have to find an alternate source. Can you offer any other solution? Thank you both.
 
W

wireguru

Senior Member
vikkaraja said:
yes, it is 3 wire Delta system. So there is no way I can use this panel for my need, I would have to find an alternate source. Can you offer any other solution? Thank you both.
Click to expand...

what exactly are you trying to do? L6-20 is a 240v only plug, 2 hots and a ground. You arent supposed to get 120 out of it.

If you need 120 from your 240v delta panel, you're going to need a transformer.
 
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vikkaraja

Member
I do not need 120,just 240. What really concern me is 240V reading with a Fluke87 DMM between ground and any of the 2 hot wire. All I want to make sure is that I am not going to be buring anything that gets plugged into this source. It makes sense now that since it is a Delta sytem without a center tapped. Thanks again.
 
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Don S.

Member
It looks like you have a 3 phase delta on which one phase has gone to ground. That?s why you read 240V between two phases and 240V from each of these phases to ground.
 
D

domnic

Senior Member
Occupation
Electrical Contractor
nema L6-20

nema L6-20

Don S. said:
It looks like you have a 3 phase delta on which one phase has gone to ground. That?s why you read 240V between two phases and 240V from each of these phases to ground.
Click to expand...
IF ONE PHASE GOES TO GROUND YOU WILL READ 0 VOLTS TO GROUND FROM ONE PHASE TO GROUND THE VOLTAGES THAT WORE LISTED CANNOT BE RIGHT I WOULD TRY A DIFFERENT METER.
 
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