multi-voltage switching device

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PBUNBURY

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I am struggling to find an objection to the use of 120v and 277 volt switch loops on the same 2-pole 20A wall switch.

My associates do this and seem to get it past the Dept of Building and Safety and I think it is crazy.

The person replacing this switch will think he has secured the power with a single circuit breaker in the 120v panel then start handling the device and take 277v thru the heart and die.

If not in the code maybe it should be.

Paul M. Bunbury
Electrical Engineer
 
Re: multi-voltage switching device

Originally posted by PBUNBURY:
I am struggling to find an objection to the use of 120v and 277 volt switch loops on the same 2-pole 20A wall switch.
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That is a violation of 404.8(B). The only way it could be done to meet the NEC is to have 2 separate switches (1 for the 120V and 1 for the 277V) installed in an enclosure equipped with identified, securely installed barriers between the adjacent devices.

[ June 16, 2005, 03:53 PM: Message edited by: GG ]
 
Re: multi-voltage switching device

GG, the argument could be that 404.8(B) is talking about "Devices" as in plural, not one device with multiple circuits landed on it.

The problem would be (which would prohibit this practice) is there would be no way to comply with 210.7(B) in the 2005 NEC, earlier NEC cycles only covered receptacles.


Roger

[ June 16, 2005, 04:09 PM: Message edited by: roger ]
 
Re: multi-voltage switching device

That is a violation of 404.8(B).
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404.8(B) makes the distinction of two switches. A double pole switch isn't two switches so I don't see how that would apply. Besides if one circuit is 120 volts and the other is 277 volts does that mean that the voltage between the two systems is more than 300 volts?
 
Re: multi-voltage switching device

This came up before and Charlie the utility guy pointed out it is a UL violation to use a double pole switch with two different voltage systems.
 
Re: multi-voltage switching device

I remember that thread but I don't recall it being an NEC violation.
 
Re: multi-voltage switching device

Originally posted by infinity:
Besides if one circuit is 120 volts and the other is 277 volts does that mean that the voltage between the two systems is more than 300 volts?
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Probably see This thread. The graphic being discussed in that thread was this one.

1008709181_2.gif


Roger
 
Re: multi-voltage switching device

The problem would be (which would prohibit this practice) is there would be no way to comply with 210.7(B) in the 2005 NEC, earlier NEC cycles only covered receptacles.
Click to expand...
Does 210.7(B) in the 2005 NEC apply to switches? The section 210.7 is titled Branch Circuit Receptacle Requirements.
 
Re: multi-voltage switching device

--------------------------------------------------------------------------------
Originally posted by infinity:
Besides if one circuit is 120 volts and the other is 277 volts does that mean that the voltage between the two systems is more than 300 volts?
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Click to expand...
The reason that I mentioned this was because I tested two adjacent devices in the field (120 and 277 volt) and measured around 180 volts. After reading Charlie's old post I now know why.
 
Re: multi-voltage switching device

Originally posted by infinity:
Does 210.7(B) in the 2005 NEC apply to switches? The section 210.7 is titled Branch Circuit Receptacle Requirements.
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Actually I don't think it could due to the title, although I think there may be some intent that it would. I have to wonder why the wording has changed from "receptacles" in 210.7(C) in 2002 to "devices or equipment" in 210.7(B) in the 2005.

What would you think the reason for this would be if it was only addressing receptacles? There would be no reason for the wording change.

Roger
 
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