NEC
- Thread starter mjfeigl
- Start date
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- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: NEC
Only if they used a three-pole breaker. If they used three single pole breakers, you have a violation. All three poles must be opened at the same time, if the breaker trips on overcurrent, or if you wish to turn off the circuit for maintenance. Reference: Exception 2 to 210.4(c).
Only if they used a three-pole breaker. If they used three single pole breakers, you have a violation. All three poles must be opened at the same time, if the breaker trips on overcurrent, or if you wish to turn off the circuit for maintenance. Reference: Exception 2 to 210.4(c).
allenwayne
Senior Member
Re: NEC
Charlie wouldn`t you have to use a 3 pole breaker to utilize A & C.A & B yes but with A & C That would require spanning 3 buss bars.
Charlie wouldn`t you have to use a 3 pole breaker to utilize A & C.A & B yes but with A & C That would require spanning 3 buss bars.
peter d
Senior Member
- Location
- New England
Re: NEC
Roger, it's a lost cause.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: NEC
Because these are all line-to-line loads, you could use three single pole breakers with identified handle ties. A three pole breaker isn't required.
210.4 doesn't apply, as this is not a multiwire branch circuit (no nuetral). The code reference would actually be 240.20(B)(3).
Because these are all line-to-line loads, you could use three single pole breakers with identified handle ties. A three pole breaker isn't required.
210.4 doesn't apply, as this is not a multiwire branch circuit (no nuetral). The code reference would actually be 240.20(B)(3).
pierre
Senior Member
- Location
- Westchester County, New York
Re: NEC
You might want to also take a look at 440.62(C), as the loads may exceed 50%.
You might want to also take a look at 440.62(C), as the loads may exceed 50%.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: NEC
A series of 2-pole breakers, one above another, would in turn span A-B, then B-C, then C-A, then A-B, and so forth. The C-A would be identical in function to an A-C.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: NEC
But if you run a neutral, you would have (by definition) a multi-wire branch circuit, and 210.4 would apply, even if no loads are connected to the neutral.
chicar
Senior Member
- Location
- Lancaster,Pa
Re: NEC
What is the total load on this 3 pole breaker?
What is the total load on this 3 pole breaker?
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: NEC
But it still wouldn't require a multiple breaker. Identified handle ties would satisfy the rule
[ March 01, 2006, 05:57 PM: Message edited by: ryan_618 ]
But it still wouldn't require a multiple breaker. Identified handle ties would satisfy the rule
[ March 01, 2006, 05:57 PM: Message edited by: ryan_618 ]
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: NEC
To be anally correct, the order would actually be A-B, C-A, B-C, etc., which of course does equal out.
Re: NEC
If you go back and read the original question it really is a good question.
Who ever arranged the phasing of the 3- 208 volt single phase units on this 3 pole breaker knew what they were doing and not a handyman , the question is this arrangement code compliant and safe.
I don't have the answer myself on this interesting question but some good points have been brought up on the subject......such as the fact they do not share a neutral and would not be considered a multi-wired branch circuit , and what are the loads of the units ? Can you do this ?
Again good question , I have a hunch that this would be ok as long as the breaker would accept 2 wire under each terminal and the combined loads did not exceed 80% of the breaker rating but again this is just a stab on my part and interested on the real facts just like you are.
If you go back and read the original question it really is a good question.
Who ever arranged the phasing of the 3- 208 volt single phase units on this 3 pole breaker knew what they were doing and not a handyman , the question is this arrangement code compliant and safe.
I don't have the answer myself on this interesting question but some good points have been brought up on the subject......such as the fact they do not share a neutral and would not be considered a multi-wired branch circuit , and what are the loads of the units ? Can you do this ?
Again good question , I have a hunch that this would be ok as long as the breaker would accept 2 wire under each terminal and the combined loads did not exceed 80% of the breaker rating but again this is just a stab on my part and interested on the real facts just like you are.
I think one thing to watch is, if you have a 15A 208V load and decide to connect up three of them (one each to each phase) via a 3 pole breaker, your amp load will be more than 15A per phase.
The VA of one load is 15*208 which is 3120VA. Three units would have to draw 9360 VA. In a 3-phase system, the current on each leg for a 9360 VA balanced load will be 9360/208/1.73 = 26 amps per phase.
Hopefully, those air conditioners draw just under 10 amps each, or else you're overloading the breaker.
The VA of one load is 15*208 which is 3120VA. Three units would have to draw 9360 VA. In a 3-phase system, the current on each leg for a 9360 VA balanced load will be 9360/208/1.73 = 26 amps per phase.
Hopefully, those air conditioners draw just under 10 amps each, or else you're overloading the breaker.
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