210.8a less than 150v

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Bill_F

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Former Eng Student, and also electician helper
Greetings... hope everyone had a good day off yesterday.
Appreciate the tons of discussion on the 2020 code, ref EVSE.
Simple question on on interpretation...
Code states... thu 250 volt receptacles ..... supplied by.... 150 volts or less....
So... in a garage receptacle, wired for 240 Volts, then GFCI is NOT required?
Thanks.
Appreciate all the super experienced folks here!
Bill
 
210.8(A) refers both to the receptacle rating and the voltage to ground of the supply system. A 120/240V supply system is only 120V to ground--each conductor is either 0V (the neutral) or 120V (the ungrounded conductors) to ground. So on a 120/240V supply system, all the receptacles in the areas specified in 210.8(A) will require GFCI.

If you had a 240V 2-wire supply system, e.g. created by a transformer, then you could install a 240V receptacle in one of the locations specified, and it would not require GFCI. A 240V 2-wire supply system is 240V to ground (either because one of the two conductors is grounded, or by definitional fiat if it is ungrounded).

Cheers, Wayne
 
Wayne,
Thank you very much! Read your responses thu' the years, & always find them awesome. And appreciate your time.

This example is a single phase, 3 wire (service drop) residential, & as u said 120 / 240 volt.

So.... if I understand correctly, even if the EVSE is simply 240V ( no neutral required, or pulled), 2 hots, it would STILL require GFCI?

And I understand it could be more reasonable to pull a neutral for future.
Thank u very, very much for interpretation!
Bill
 
Bill_F said:
This example is a single phase, 3 wire (service drop) residential, & as u said 120 / 240 volt.

So.... if I understand correctly, even if the EVSE is simply 240V ( no neutral required, or pulled), 2 hots, it would STILL require GFCI?
Click to expand...
Correct, because each of the ungrounded conductors is only 120V to ground.

As a completely impractical way to work around that, and to illustrate what the 150V to ground limitation means, one could install a 240V : 240V transformer as an SDS, and on the secondary side connect one of the two conductors to the grounding electrode system. The ungrounded conductor on the secondary side would now be at 240V to ground, and you could supply a 240V receptacle without requiring GFCI.

Cheers, Wayne
 
OK, accepted & appreciated! Thanks.

And yup, either ungrounded 240v hot WOULD be 120v to ground, from the usual POCO center tapped, but I was stuck on AT the recpt, there would be no neutral. But yes, an EGC.

Guess the step back, long view .... "the supply" ... WOULD be 120V to ground (each 240 hot) IF measured to center tap.
;)

Thanks! Enjoy your day emensely!
 
I've got a question closely related for this thread.
Commercial Kitchen. Service is a 3P Wye.
Have a few 3P dishwashers going in. Assuming they will be corded with a receptacle for cleaning.

210.8(B) states receptacles rated 150V or less to ground
Will the Hi Leg of the wye system get me out of installing a GFCI? Two legs are 120>Ground but that third is 208>ground.
I hope so, cause one dishwasher is 75A and I don't know of any 3P GFCI breakers over 60A.

Thanks in advance and hope everyone is enjoying their thanksgiving holiday
-Ben
 
PullinWires said:
210.8(B) states receptacles rated 150V or less to ground
Will the Hi Leg of the wye system get me out of installing a GFCI? Two legs are 120>Ground but that third is 208>ground.
I hope so, cause one dishwasher is 75A and I don't know of any 3P GFCI breakers over 60A.
Click to expand...
A 3Ø Wye system does not have one phase that is a higher voltage than the other two. That would be a 3Ø, 4-wire Delta system. Which system do you actually have?

Welcome to the Forum. :)
 
PullinWires said:
Commercial Kitchen. Service is a 3P Wye.
Have a few 3P dishwashers going in. Assuming they will be corded with a receptacle for cleaning.

210.8(B) states receptacles rated 150V or less to ground
Will the Hi Leg of the wye system get me out of installing a GFCI? Two legs are 120>Ground but that third is 208>ground.
Click to expand...
As pointed out, the voltages you are describing are for a 3P 4W high leg delta, not a 3P Wye. So let's amend the question to be for a 3P 4W high leg delta.

The definition of "voltage to ground" in Article 100 only applies to single conductors:

Voltage to Ground. For grounded circuits, the voltage between the given conductor and that point or conductor of the circuit that is grounded; for ungrounded circuits, the greatest voltage between the given conductor and any other conductor of the circuit.
Click to expand...

I'm a bit surprised the NEC doesn't spell out how to apply the definition to a circuit (unless I've overlooked a section). The obvious way to me to do that would be to say the "voltage to ground" of a circuit is the largest "voltage to ground" of any of the conductors of that circuit. In which case a 3P circuit on a 3P 4W high leg delta would be 208V to ground, and receptacles on it would be exempt from 210.8(B).

But if for some reason you said that the voltage to ground of a circuit was the average or minimum voltage to ground of the ungrounded conductors, then you'd get a different answer.

Cheers,
Wayne
 
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