Use of 6-20P plug/receptacle 250V on a 277V circuit.

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sky_dvr

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I went to exchange some older lighting out in a factory today. The lights are connected to single receptacle boxes through a cord with a 6-20P plug. My issue is that the plug and receptacle are rated 250V while the circuit is actually a 277V.... I did not quote exchanging the plug / receptacle combination but believe that it is required.

My fist post :bye:
 
sky_dvr said:
I went to exchange some older lighting out in a factory today. The lights are connected to single receptacle boxes through a cord with a 6-20P plug. My issue is that the plug and receptacle are rated 250V while the circuit is actually a 277V.... I did not quote exchanging the plug / receptacle combination but believe that it is required.

My fist post :bye:
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The voltage needs to match the configuration of the Receptacle and Plug.



JAP>
 
Or to be more clear, the configuration of the receptacle and Plug need to match the voltage they are supplied from.

JAP>
 
sky_dvr said:
I went to exchange some older lighting out in a factory today. The lights are connected to single receptacle boxes through a cord with a 6-20P plug. My issue is that the plug and receptacle are rated 250V while the circuit is actually a 277V.... I did not quote exchanging the plug / receptacle combination but believe that it is required.

My fist post :bye:
Click to expand...
Welcome to the forum.
I agree with jap, plugs got to match the voltage. That would get expensive fast.

I would likely not use the flex cord and plugs. Unless they are part of a factory assembly they should not be used at all.
 
sky_dvr said:
I went to exchange some older lighting out in a factory today. The lights are connected to single receptacle boxes through a cord with a 6-20P plug. My issue is that the plug and receptacle are rated 250V while the circuit is actually a 277V.... I did not quote exchanging the plug / receptacle combination but believe that it is required.

My fist post :bye:
Click to expand...

Welcome to the forum!

Apparently they have worked fine for a long time so from an operational standpoint they are not a problem. However, from a safety and code compliant standpoint, they should be replaced with the correct rated equipment, or eliminated. The least expensive solution might be to hard wire them with 6' factory fixture whips and eliminate the receptacles. I would assume the new fixtures have a disconnect switch built in.
 
GoldDigger said:
May be thinking of the newer linear fluorescent fixtures that have an integral quick disconnect plug for ballast changes?
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that was my thought, but over the last 7 years, the variety of fixtures we install is pretty slim.
It's a code requirement for any fixture with a ballast or driver, isn't it?
 
Jim1959 said:
that was my thought, but over the last 7 years, the variety of fixtures we install is pretty slim.
It's a code requirement for any fixture with a ballast or driver, isn't it?
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No.

410.130(G) Disconnecting Means

(1) General. In indoor locations other than dwellings and
associated accessory structures, fluorescent luminaires that
utilize double-ended lamps and contain ballast(s) that can
be serviced in place shall have a disconnecting means either
internal or external to each luminaire. For existing
installed luminaires without disconnecting means, at the
time a ballast is replaced, a disconnecting means shall be
installed. The line side terminals of the disconnecting
means shall be guarded.
 
The NEMA 6-20 configuration is intended for '250V'. But that is likely not the actual voltage rating of the plug and receptacle. The configuration is like a standard color code.

If, in that facility, the 6-20 configuration is only used for 277V, and if the actual voltage handling of the devices exceeds 277V, then IMHO it is a kosher install. The NEC requirement is not to follow NEMA configurations, it is to use different configurations for different voltages.

Good luck documenting the actual voltage rating, however.

-Jon
 
jap said:
The voltage needs to match the configuration of the Receptacle and Plug.



JAP>
Click to expand...

jap said:
Or to be more clear, the configuration of the receptacle and Plug need to match the voltage they are supplied from.

JAP>
Click to expand...

ActionDave said:
Welcome to the forum.
I agree with jap, plugs got to match the voltage. That would get expensive fast.

I would likely not use the flex cord and plugs. Unless they are part of a factory assembly they should not be used at all.
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jumper said:
I agree with Jap, 406.3 and 406.7.
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I think more correctly, would be to say it has to meet or exceed the system voltage.

For instance, many of our customers have standardized with 600v rated receps on their 480v systems. Don't ask me why....
 
winnie said:
The NEMA 6-20 configuration is intended for '250V'. But that is likely not the actual voltage rating of the plug and receptacle. The configuration is like a standard color code.

If, in that facility, the 6-20 configuration is only used for 277V, and if the actual voltage handling of the devices exceeds 277V, then IMHO it is a kosher install. The NEC requirement is not to follow NEMA configurations, it is to use different configurations for different voltages.

Good luck documenting the actual voltage rating, however.

-Jon
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What do you mean if the configuration is intended for 250v that it's not likely the actual voltage rating of the plug?

And what part of a receptacle that is labeled 250v but fed 277v would ever be kosher?

Jap>
 
Welcome to the forum. You need NEMA 7-20 (or 7-15 or 7-30) plugs and receptacles for 277V. Putting 277V on a 6-20 is not right at all, regardless of if it works. 110.3(B) is the first violation that comes to mind.

It would be markedly cheaper to hardwire if possible; 7-20 plugs and receptacles are considerably more expensive than NEMA 6-xx plugs and receptacles. I want to say that a 6-20 plug cap and a 6-20 receptacle (which are designed for 2 hots, either from a 208V or 240V system, and a ground) are about a fifth the cost ($11 per pair vs $60) of 277V NEMA 7 series (which are polarized; 277V on small angled hot pin, neutral on larger angled pin, and a ground).

eta: I've worked on a few 265/277V PTACs; all were hardwired.
 
jap said:
What do you mean if the configuration is intended for 250v that it's not likely the actual voltage rating of the plug?

And what part of a receptacle that is labeled 250v but fed 277v would ever be kosher?

Jap>
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What I am saying is that the NEMA plug configuration is similar to insulation color code, the electrons don't care about the slot configuration, only about the component spacing and insulation characteristics.

Compare the construction of different 'California Style' twist lock devices.
http://www.lockingpowercords.com/category/31-hubbell-50a-twist-lock.aspx
They are likely all the same in terms of actual voltage withstand capability.

The actual insulation and creepage distance characteristics of an 6-20 device are probably exactly the same as 5-20 and 7-20 devices, although as I said it may be impossible to get documentation of this.

The NEC requirement is to use different configurations for different voltages. So it would not be acceptable to use 6-20 devices for both 120V and 240V in a single facility. But it would be legal to use 6-20 devices for 120V if that were the only use.

I claim that if you could document that the existing 6-20 devices had insulation and spacing suitable for 277V, and that 6-20 devices were not used at 240V elsewhere in the same facility, then the normal association with that configuration and 240V is not a problem.

-Jon
 
Cow said:
I think more correctly, would be to say it has to meet or exceed the system voltage.

For instance, many of our customers have standardized with 600v rated receps on their 480v systems. Don't ask me why....
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I tried to say something similar fairly recently here and it wasn't accepted all that well. Not necessarily involving 600 volt rated receptacles, but still involving lesser actual operating voltage then what was marked on the device.:blink:
 
kwired said:
I tried to say something similar fairly recently here and it wasn't accepted all that well. Not necessarily involving 600 volt rated receptacles, but still involving lesser actual operating voltage then what was marked on the device.:blink:
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Don't worry, I can take it.;)

These guys can debate code all day, but I know there is no safety hazard in the real world when this is done.
 
winnie said:
I claim that if you could document that the existing 6-20 devices had insulation and spacing suitable for 277V, and that 6-20 devices were not used at 240V elsewhere in the same facility, then the normal association with that configuration and 240V is not a problem.

-Jon
Click to expand...

To me that would simply be bad practice.


JAP>
 
Cow said:
Don't worry, I can take it.;)

These guys can debate code all day, but I know there is no safety hazard in the real world when this is done.
Click to expand...

277v landed on a receptacle that is labeled 250v is a safety hazard period.

JAP>
 
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