What is a "Red Leg" panel?

[dnem]

This might be fine for a small building, but a large facility that has a color or marking already established ( I have been in mills and factories that have used Blue, Red, and even Purple) should not have another color introduced (added) into the system.


Roger

I agree about the large already established facility not changing their color code but I think you would still have to fall back to the ?effective? wording of 110.15.

The most common color code in use is black, red, blue for systems 120v to ground and brown, orange, yellow for 480v systems [straight 240v deltas vary by contractor and/or area in the country]. . According to that practice, the high leg 120/240 delta is usually coded black, orange, blue with the B phase the high leg.

This being the usual practice, which of the following phases would be assumed as the high leg ?

Here too. Except the panel I was in last week. It was marked A (blue) B (yellow) C (red)

I would think yellow is the ?odd ball? and yellow is the B phase so therefore most likely the high leg. . But that didn?t prove to be the case

Here too. Except the panel I was in last week. It was marked A (blue) B (yellow) C (red) with C as the high leg.

It wouldn?t be reasonable to require a change in a large established facility but it should be otherwise marked ?by other effective means?. . Some type of marking should be added if the original chosen route isn?t ?effective?.

David

 

[tom baker]

Red Leg is an older term for this system. Our POCO no longer provides this voltage but there are lots still in service.
The NEC uses orange to mark the high leg. Its in the B phase for NEC, but most POCOs want the C phase to be the high leg in a meter.
A high leg system is also called a
Wild Leg
Stinger Leg
Bastard Leg

They are pretty easy to find as the panels will have two breakers and a space, etc.

Also the breakers have to be delta rated, as the voltage is 208 to ground on one leg. A 120/240 slash rated breaker won't clear a fault on the 208 phase.
Delta rated breakers are 10X the cost of a slash rated breaker...

 

[dnem]

A 120/240 slash rated breaker won't clear a fault on the 208 phase.

I don't understand that concept. . How does the breaker know if it's connected to a delta 208v high leg or a 208 wye leg ? . It's monitoring the current so why would delta or wye matter.

Delta rated breakers are 10X the cost of a slash rated breaker...

I think that's the real answer. . There is no actual need for a delta rating. . It's just another way for the manufacturer to make extra cash. . I'm thinking that the 120/240 slash rated breaker won't clear enough money out of your pocket to satisfy the manufacturer.

Am I wrong ?

What's different about a Delta breaker ?

David

 

[roger]

The most common color code in use is black, red, blue for systems 120v to ground and brown, orange, yellow for 480v systems [straight 240v deltas vary by contractor and/or area in the country]. . According to that practice, the high leg 120/240 delta is usually coded black, orange, blue with the B phase the high leg.

This being the usual practice, which of the following phases would be assumed as the high leg ?

David

The one that pushes the tester to around 208 volts, I don't put much faith in color codes.

I would think yellow is the “odd ball” and yellow is the B phase so therefore most likely the high leg. . But that didn’t prove to be the case

See my sentence above.




Roger

 

[pete m.]

Dnem,

I don't understand that concept. . How does the breaker know if it's connected to a delta 208v high leg or a 208 wye leg ? . It's monitoring the current so why would delta or wye matter.

See 240.85 second paragraph and the FPN. The logic, as I understand it, is the same as applying a 250volt rated fuse in a 480volt circuit. If the OCD isn't rated to handle the applied voltage the overcurrent or overload condition may not be effectively cleared.

Pete

 

[jim dungar]

I don't understand that concept. . How does the breaker know if it's connected to a delta 208v high leg or a 208 wye leg ? . It's monitoring the current so why would delta or wye matter.



I think that's the real answer. . There is no actual need for a delta rating. . It's just another way for the manufacturer to make extra cash. . I'm thinking that the 120/240 slash rated breaker won't clear enough money out of your pocket to satisfy the manufacturer.

Am I wrong ?

What's different about a Delta breaker ?

David

A Delta breaker as mentioned in 408.36(E) is a special animal that is no longer allowed in new panelboards. Do not confuse this item with the slash (i.e. 120/240V) and non-slash (240V) rated 2-pole breakers mentioned in 240.85.

A non-slash rated breaker requires line-ground clearance or insulation of the higher L-L voltage rather than the lower L-N voltage. In some cases the venting path of arcing gasses may even need to be modified.

 

[Jim W in Tampa]

I start a new remodel of a factory in morning.One of the first things i will do is verify what i have.Never assume anything , the engineer might already assumed and be wrong.In area i am in it will likely be 480 no problem ,but in 11 hours that might all be wishfull thinking.Meter everything you touch before even turning first breaker on.Seen results when without thinking i told a helper to pull meter and give us a 120 receptacle,ouch

 

[dnem]

Dnem,

I don't understand that concept. . How does the breaker know if it's connected to a delta 208v high leg or a 208 wye leg ? . It's monitoring the current so why would delta or wye matter.

See 240.85 second paragraph and the FPN. The logic, as I understand it, is the same as applying a 250volt rated fuse in a 480volt circuit. If the OCD isn't rated to handle the applied voltage the overcurrent or overload condition may not be effectively cleared.

Pete

I don?t see comparing a 250v rated fuse in a 480v circuit as being comparable to a 120/208 rated breaker in a 208 delta supplied panel. . 208v is 208 v. . The only difference is the voltage to ground. . The 120/208 wye will have 120v to ground, while the 208 from a corner grounded delta will have 208v to ground.

But the breaker is not connected to ground. . It?s connected to phase wires that have 208v in both examples. . The case of the breaker is sufficiently insulated and the breaker lugs physically removed from the panel housing or anything else bonded to ground so that any voltage to ground ranging from zero up to phase voltage shouldn?t matter.

I agree we should follow code requirements but that doesn?t prevent me from questioning them.

?If the OCD isn't rated to handle the applied voltage ?..? then the installation isn?t code compliant and should be changed, I agree.

?If the OCD isn't rated to handle the applied voltage the overcurrent or overload condition may not be effectively cleared.? . I do question the truth in that complete statement. . I don?t believe the breaker would have any problem clearing the fault as long as it doesn?t pass its top current interrupting rating limit. . Its hard for me to believe that all of the specifics of 240.85 weren?t written with heavy influence from manufacturers.

David

 

[jim dungar]

The case of the breaker is sufficiently insulated and the breaker lugs physically removed from the panel housing or anything else bonded to ground so that any voltage to ground ranging from zero up to phase voltage shouldn’t matter.

David,

Where did you get any information that all breakers are rated with their L-G voltage equal to their L-L voltage?

 

[dnem]

The case of the breaker is sufficiently insulated and the breaker lugs physically removed from the panel housing or anything else bonded to ground so that any voltage to ground ranging from zero up to phase voltage shouldn?t matter.

David,

Where did you get any information that all breakers are rated with their L-G voltage equal to their L-L voltage?

I said, ?shouldn?t matter?
You said, ?breakers are rated?

There can be a difference between a rating requirement and actual performance of the product. . It?s the difference between legality and reality.

David

 

[Rockyd]

Only four colors are ever supposed to matter according to the NEC.

202.6(A), and 200.6(B) qualify white or raised ridge(brewers cord).

250.119 qualify green, or green with yellow stripage.

110.15 High leg marking to be orange.

230.56 Service conductor to be marked orange.

408.3(E) Tells us that we have to have "B" phase high leg in the center.

409.102(B) Same as above now industrial panels.

Extra credit

504.80(C) Light blue for intrinsically wired.

 

[pete m.]

But the breaker is not connected to ground. . It?s connected to phase wires that have 208v in both examples. . The case of the breaker is sufficiently insulated and the breaker lugs physically removed from the panel housing or anything else bonded to ground so that any voltage to ground ranging from zero up to phase voltage shouldn't matter.

Is it possible for a ground fault to occur on the load side of the breaker on the phase that has the elevated (208) voltage to ground? If it is possible then the "slash" rated breaker would fall short with respect to the lower of the two voltage values that the breaker has been approved for. That is the problem.

The example I gave of a 250v fuse in a 480v circuit might be a bit extreme in relation to the slash rated breaker but I believe that it is the same in principle. The OCD has to have a voltage rating equal to or greater than the applied voltage of the circuit. If it doesn't, does this mean that any overcurrent or overload condition will not be cleared? I don't know the answer but I will make a blind leap of faith that UL or whatever NRTL that has listed these OCD at a certain voltage did so because they did not perform as intended outside of their respective voltage classification.

?If the OCD isn't rated to handle the applied voltage the overcurrent or overload condition may not be effectively cleared.? . I do question the truth in that complete statement. . I don?t believe the breaker would have any problem clearing the fault as long as it doesn?t pass its top current interrupting rating limit. . Its hard for me to believe that all of the specifics of 240.85 weren?t written with heavy influence from manufacturers.

Do you believe that a 250v rated fuse would be able to effectively clear an overload condition if applied in a 480v circuit? I question the ability of it to do so. Although I guess you could be correct and there is no actual need for voltage ratings on OCD's since, as you say, they are only responsive to current.

Pete

 

[LarryFine]

I don?t see comparing a 250v rated fuse in a 480v circuit as being comparable to a 120/208 rated breaker in a 208 delta supplied panel. . 208v is 208 v. . The only difference is the voltage to ground. . The 120/208 wye will have 120v to ground, while the 208 from a corner grounded delta will have 208v to ground.

But the breaker is not connected to ground. . It?s connected to phase wires that have 208v in both examples. . The case of the breaker is sufficiently insulated and the breaker lugs physically removed from the panel housing or anything else bonded to ground so that any voltage to ground ranging from zero up to phase voltage shouldn?t matter.

There is another difference between 208v line-to-neutral and 208v line-to-line: The 208v line-to-line would have two breakers in series between the lines.

 

[roger]

Only four colors are ever supposed to matter according to the NEC.

202.6(A), and 200.6(B) qualify white or raised ridge(brewers cord).

250.119 qualify green, or green with yellow stripage.

110.15 High leg marking to be orange.

230.56 Service conductor to be marked orange.

408.3(E) Tells us that we have to have "B" phase high leg in the center.

409.102(B) Same as above now industrial panels.

Extra credit

504.80(C) Light blue for intrinsically wired.

Rocky, you missed 322.120, (terminal) 400.22(C), 424.25, and 517.160(A)(5) (yes, orange, brown, and yellow is a mandated color code)

Roger

 

[iwire]

408.3(E) Tells us that we have to have "B" phase high leg in the center.

Well it does....then it doesn't.

We can match existing placement.

 

[Rockyd]

Well Roger,

Does a serving of Crow mean I have to recognize black now too? Had to go out and beat the head against a rock when I read the heat cable and hospital gig, would have missed that one for sure!

Will have to go have an icy coldy with Bob sometime, he allowed me some redemption.

 

[roger]

Rocky, we all seem to aquire a taste for crow hanging around here.

Maybe we can all sit and have a cold one together someday.

Roger

 

[Rockyd]

If I get out east, that's a good possibility, plus I can stay at a Holiday Inn Express, and according to the commercials, I'll be at least 25% smarter for it.

 

[augie47]

Rocky, we all seem to aquire a taste for crow hanging around here.

Roger

amen! I am served a bit almost weekly.
the older one gets the more accustom to the taste, I believe

 

[roger]

the older one gets the more accustom to the taste, I believe

LOL :grin:

Roger