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

[winnie]

To me that would simply be bad practice.


JAP>

I agree. You are required to use different plug configurations, and the NEMA configurations are a great way to implement this.

However we are talking about an existing installation implementing what we agree is a bad practice.

I do not believe that it is necessarily required to spend money and time fixing this.

-Jon

 

[jap]

I do not believe that it is necessarily required to spend money and time fixing this.

-Jon

We'll just have to agree to disagree and I'm glad I work with professionals who would spend the time and money to fix it.


JAP>

 

[winnie]

Fair enough.

Just to be clear, I am 90% in agreement with you. I am _not_ advocating leaving a code violation in place.

I am making the claim that this existing install may not be a code violation, and that if not it could remain even if it were not 'best practice'. If (and only if) these particular 6-20 devices can be documented as having suitable characteristics for 277V (other than configuration, which IMHO is similar to a color code), and if the 6-20 configuration is not used for any other voltage in that facility, then IMHO it is not a code violation.

IMHO the threshold for 'you must change a working installation' is 'does this meet code' rather than 'is this best practice'.

-Jon

 

[winnie]

It took me a while to find this; good luck for an old installation:
https://cdn.automationdirect.com/static/specs/wiringdevicesplugsconnsreceps.pdf

In particular, look at the 3rd page. _All_ of the devices have the same 'maximum working voltage' of 600VAC/250VDC, no matter what the NEMA configuration and no matter the voltage associated with that configuration.

-Jon

 

[Cow]

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

JAP>

You're misunderstanding what Kwired and myself have posted.

 

[jap]

You're misunderstanding what Kwired and myself have posted.

I don't think I am.

Most everyone knows that the conductive parts inside of cord caps and receptacles are probably all rated at a higher voltage than what's written on the face of it. That's no secret.

I have 600v Rated 60 amp pin and sleeve connectors on temporary panels that are simply 120/240 single phase.

As Winnie indicated there's documentation that the guts on some cord connectors are all rated at 600v even though the connectors themselves may read 240, 277, 120 or whatever.

When I say 277v landed on a receptacle labeled 250v is a safety hazard period is not because the 250v receptacle or the male plug is not rated to handle the voltage, it's because of the danger of someone plugging a lower voltage piece of equipment into a receptacle that's fed with a higher voltage than what the receptacle indicates on the face.

Which is what the OP is up against.

Tell you what, I'll wire a 277v circuit up to a 125v duplex receptacle and let you plug your brand new hilti drill into it and pull the trigger.
Maybe then you'll understand where I'm coming from.

JAP>

 

[Cow]

I don't think I am.

Most everyone knows that the conductive parts inside of cord caps and receptacles are probably all rated at a higher voltage than what's written on the face of it. That's no secret.

I have 600v Rated 60 amp pin and sleeve connectors on temporary panels that are simply 120/240 single phase.

As Winnie indicated there's documentation that the guts on some cord connectors are all rated at 600v even though the connectors themselves may read 240, 277, 120 or whatever.

When I say 277v landed on a receptacle labeled 250v is a safety hazard period is not because the 250v receptacle or the male plug is not rated to handle the voltage, it's because of the danger of someone plugging a lower voltage piece of equipment into a receptacle that's fed with a higher voltage than what the receptacle indicates on the face.

Which is what the OP is up against.

Tell you what, I'll wire a 277v circuit up to a 125v duplex receptacle and let you plug your brand new hilti drill into it and pull the trigger.
Maybe then you'll understand where I'm coming from.

JAP>

Alright Jap, one more time here. I'll repost myself for the sake of clarification:

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....

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:

I am talking about using receps with a voltage rating that meet OR EXCEED the system voltage, just as Kwired mentioned.

 

[kwired]

Alright Jap, one more time here. I'll repost myself for the sake of clarification:





I am talking about using receps with a voltage rating that meet OR EXCEED the system voltage, just as Kwired mentioned.

Same here.

Sort of no different then using 600 volt fuses on 480 volts, or even 240 volts.

 

[jap]

Alright Jap, one more time here. I'll repost myself for the sake of clarification:



I am talking about using receps with a voltage rating that meet OR EXCEED the system voltage, just as Kwired mentioned.

And I'm talking about using recepts with a voltage rating that MATCH the system voltage.
That way we don't have to waste time trying to figure out what the person before us was trying to do.

Finding recepts and plugs that don't match system voltage and even finding 600v fuses used in 600v disconnects for 240v applications makes me question what other shortcuts those who installed them might have took.

There's a certain normality of installation practices that I feel most Electrical professionals expect to find on the job and I don't feel buying an extra large T Shirt for the simple fact that it will be large enough to cover everyone in the family is normal practice.

But that's just me.

Jap>

 

[JFletcher]

I dont see a particular problem* with using, say, a 480V twist-lock plug and receptacle for 208V (even tho it would be confusing and a waste of money) tho putting 277V on a plug designation that is by standard, 250V or less is a problem for the reason jap mentioned many posts up.

and I stand corrected on NEMA 7 series receptacles and cords being way expensive. Unless they are counterfeit, Leviton locking 7-15p&r are about $15 a set depending on the plug (straight, 90*). Not too much more than 6-20s.

I still think that putting 277V on 240 plugs and receptacles is a 110.3(B) violation at the minimum.

*Actually, I do. System voltage should be readily discernible by the plug/receptacle configuration, save for 6-series, which can be 208V or 240V. If you plug in something, it should operate correctly, not go "whiiiiirrr" if it's made for 480V and 208V is supplied, nor "poof" if there's 277 or 480V on a NEMA 6-xx receptacle.

 

[ActionDave]

......*Actually, I do. System voltage should be readily discernible by the plug/receptacle configuration, save for 6-series, which can be 208V or 240V. If you plug in something, it should operate correctly, not go "whiiiiirrr" if it's made for 480V and 208V is supplied, nor "poof" if there's 277 or 480V on a NEMA 6-xx receptacle.

In this case it is a light, so the odds of somebody getting up on a lift and unplugging a light to plug in his 240V table saw are pretty slim.

 

[Cow]

And I'm talking about using recepts with a voltage rating that MATCH the system voltage.
That way we don't have to waste time trying to figure out what the person before us was trying to do.

Finding recepts and plugs that don't match system voltage and even finding 600v fuses used in 600v disconnects for 240v applications makes me question what other shortcuts those who installed them might have took.

There's a certain normality of installation practices that I feel most Electrical professionals expect to find on the job and I don't feel buying an extra large T Shirt for the simple fact that it will be large enough to cover everyone in the family is normal practice.

But that's just me.

Jap>

This is a design issue, not code, as you portrayed it to be.

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>

Obviously, the devices can meet or exceed the system voltage rating, even though you consider that buying "an extra large T shirt."

I've used cord and plugs for plc controlled devices the customer wanted installed that way. I'm sure you wouldn't be surprised that I didn't go and track down some special 24vdc cord ends when any typical nema configuration would work?

 

[kwired]

I've used cord and plugs for plc controlled devices the customer wanted installed that way. I'm sure you wouldn't be surprised that I didn't go and track down some special 24vdc cord ends when any typical nema configuration would work?

As long as you avoid using a 5-15 or 5-20 for such applications, the likelihood of someone coming in there with with equipment that already has same plug and thinking they can power that item is probably not that likely, especially if it is a configuration they don't already have on the premises. If you have quite a few 16-20 receptacles in use on the premises then by all means don't use a 16-20 for the 24 VDC control, but if you don't even have 480 volts on the premises then using 16-20 might be fine for some special use like that.

 

[Cow]

That's how we did it Kwired. We would buy some off-the-wall NEMA configuration that didn't match anything else just to make sure no one would plug into it.

 

[winnie]

NEC explicitly requires that when different voltages are present in a facility, that different receptacle configurations be used.

But it does not specify _which_ different configurations.

NEMA does associate configuration with voltage, but the NEMA configurations are a design choice, not code.

IMHO using standard configurations is a 'best practice'.

If a facility has 480V receptacles, but chooses to use what are typically 600V devices, than that is fine. But if there is both 480V and 600V present, using the 600V configuration for both is a violation.

Using 6-20 devices for both 208V and 240V in a single facility is also a violation.

In the OP's situation, if 6-20 devices are used for both 240V and 277V, then there is a code violation.

If the actual devices used have a 'maximum working voltage' rating < 277V, then there is a violation.

Imagine a facility with both 208/120V and 480/277V. Pretty common. But the facility as built color coded the 208V with black, purple, orange, and 480V with red, yellow, blue. Would you demand that the re-wire?

-Jon

 

[kwired]

Imagine a facility with both 208/120V and 480/277V. Pretty common. But the facility as built color coded the 208V with black, purple, orange, and 480V with red, yellow, blue. Would you demand that the re-wire?

-Jon

I think there are some that find that to be a horrible situation.

Quite honestly I trust meter readings more then I trust color coding.

 

[jap]

I've used cord and plugs for plc controlled devices the customer wanted installed that way. I'm sure you wouldn't be surprised that I didn't go and track down some special 24vdc cord ends when any typical nema configuration would work?

After hearing all the rest, this doesn't surprise me one bit.


JAP>

 

[Bobbyv08081]

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:

406.3