3-pole single phase

[don_resqcapt19]

408.36(E) Delta Breakers A 3-phase disconnect or overcurrent device shall not be connected to the bus of any panelboard that has less than 3-phase buses. Delta breakers shall not be installed in panelboards.

 

[Dennis Alwon]

That I can answer. Because a 3-pole breaker installed in a single phase panel will not create a multi-wire branch circuit. Look at the first sentence of the definition of MWBC. It requires there to be a voltage between the ungrounded conductors. A 3-pole breaker in a single phase panel will pick up Phase A, Phase B, and Phase A, and therefore there will not be voltage between two of the poles.

Yes but the op is not talking about a multiwire branch circuit.

 

[jim dungar]

408.36(E) Delta Breakers A 3-phase disconnect or overcurrent device shall not be connected to the bus of any panelboard that has less than 3-phase buses. Delta breakers shall not be installed in panelboards.

A delta breaker is a very special device. It only has two poles with bus bar connections, the third pole has a separate lug for the line connection instead.

 

[charlie b]

Yes but the op is not talking about a multiwire branch circuit.

I wasn't addressing the OP's question, from Post #1. I was addressing a side-question presented by 480, from Post #17.

 

[frenchelectrican]

A delta breaker is a very special device. It only has two poles with bus bar connections, the third pole has a separate lug for the line connection instead.

Yep .,, Those item is pretty rare bird around here. I think someone did post the photo here before.

They used to be common in 60-early 70's era when they bring in 3? 4W delta [ centre tapped and some case open delta centre tapped as well ] in the resdentail area and of course a bit in light commercal load centre.

Merci,Marc

 

[don_resqcapt19]

Jim,
I agree that a delta breaker is rare, but in my opinion, the wording of the section applies to more than just a delta breaker.

 

[charlie b]

. . . in my opinion, the wording of the section applies to more than just a delta breaker.

I agree. But the author chose an unfortunate title for the paragraph. I am not familiar with the NEC's writing standards. But if I see a paragraph with the title, "Delta Breakers," and if I have no interest in using such a device, I am not likely to read the article, suspecting that it would have nothing to do with my installation. However, in this case, the paragraph has two sentences, and only the second has to do with the title. The first sentence is more generally applicable, and IMHO should not have been placed under the title, "Delta Breakers."

 

[jim dungar]

Jim,
I agree that a delta breaker is rare, but in my opinion, the wording of the section applies to more than just a delta breaker.

Then why the specific title of "408.36(E) Delta Breakers"? If this section applied to all 3-pole devices connected to bus bars the NEC would not need to use the word Delta.

 

[jflynn]

I am not sure about that, these two statements seems to contradict each other.








However I would think the first quote would take precedent since the second one may be referring to multipole as double pole ot 3 pole marked to indicate that it is suitable for sp operation.

I agree dennis-it makes you wonder the intent meaning behind,- "unless marked to indicate otherwise"...

 

[jim dungar]

I agree. But the author chose an unfortunate title for the paragraph. I am not familiar with the NEC's writing standards. But if I see a paragraph with the title, "Delta Breakers," and if I have no interest in using such a device, I am not likely to read the article, suspecting that it would have nothing to do with my installation. However, in this case, the paragraph has two sentences, and only the second has to do with the title. The first sentence is more generally applicable, and IMHO should not have been placed under the title, "Delta Breakers."

If this sentence was intended to be generally applied, it would need to have been located in article 408 as it addresses "disconnects" as well as "breakers" installed in panelboards. We cannot take NEC wording out of a specific section and then say it must be used everywhere.

 

[paul]

So that would make it OK with a 208Y/120 system

I am not sure about that, these two statements seems to contradict each other.

3-pole circuit breakers are suitable for use only on 3-phase systems unless marked to indicate otherwise.

Multi-pole common trip circuit breakers rated 120/240 V ac are suitable for use in a single-phase multi-wire circuit, with or without the neutral connected to the load, where the voltage to ground does not exceed 120 V.
I am not sure about that, these two statements seems to contradict each other.

However I would think the first quote would take precedent since the second one may be referring to multipole as double pole ot 3 pole marked to indicate that it is suitable for sp operation.

I don't see where they contradict each other at all. The first is telling me that I cannot use a 3P breaker in a 1Ɵ panel. That's easy enough and makes sense. It does not say that I cannot use it in a 3Ɵ panel on 1Ɵ circuit. Nor am I prohibited from using one pole of a 2P breaker in a 1Ɵ panel.

 

[jim dungar]

According to Square D's website:
1-Phase panel instructions

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One single pole. One plug on space or may use one single pole. One two pole requires two spaces.

3-Phase panel instructions​

One ​

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single pole. One plug on space. One two pole requires two plug on spaces. One three pole requires three plug on spaces.​

​

 

[Sierrasparky]

Suppose you have 3 circuits on one device?

OK, I know it's a long shot, but by the '08, a 3-pole could be used.

Who makes this device? Does it actually have seperate circuts?

 

[Dennis Alwon]

I don't see where they contradict each other at all. The first is telling me that I cannot use a 3P breaker in a 1Ɵ panel. That's easy enough and makes sense. It does not say that I cannot use it in a 3Ɵ panel on 1Ɵ circuit. Nor am I prohibited from using one pole of a 2P breaker in a 1Ɵ panel.

Paul I was saying that they seem or appear to contradict each other. I agree that they do not.

 

[480sparky]

Who makes this device? Does it actually have seperate circuts?

P&S. I assume it has tabs on the other side in order to seperate the devices.