2 lines 1 load 1 circut=wrong?

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chris kennedy said:
Are they joined at both ends?
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No they are not physically joined at both ends.



But the sure are electrically joined at both ends. :)

Again, no need for the exception to 310.4 if what we are describing was not a violation.
 
crossman said:
Do you feel that, with both switches closed, the red and black conductors are in parallel in a manner that violates the intent of 310.4?
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Actually I don't see an issue with this install and I can only guess it is not a safety issue. At least I hope not as I have done this for in line bath fans very often in the past. Is it a code issue? I don't think so but I believe it is definitely arguable, esp. since it is being debated right now.:smile:
 
Just use 1/0 conductors in the paralleled sections of the circuit, problem solved. :wink:

Roger
 
iwire said:
If that was the case 310.4 would not need the exception for that exact scenario with control circuits. :)
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We can argue this one for a long time. I feel that the exception is for the actual physical paralleling of conductors smaller than 1/0 in certain applications in raceways and cables.... not for "paralleling accomplished by switches."

Say that I had an enclosure that had a starter in it. In the cover of the enclosure, I put a start and a stop button and wire it for three-wire control. If the start button is held in, and the holding contact is closed, wire 2 and wire 3 are now in parallel. These conductors are in an enclosure, not a raceway or cable, and therefore would supposedly violate the exception. I suppose it can be said that the enclosure is also a raceway.... but I'm not sure about that.

What is your definition of electrically connected? Give me a reasonable definition, and I will see if I can come up with some absurdities concerning 310.4.

This is a great subject!:smile:
 
roger said:
Just use 1/0 conductors in the paralleled sections of the circuit, problem solved. :wink:

Roger
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Wouldn't it just be cheaper to run them to the coil of a relay that controls the power to the unit? 310.4 Ex. 2.
 
Can someone clue me in as to what is meant by "electrically joined at both ends" which appears in the first paragraph of 310.4(A)? What exactly does that mean?
 
crossman said:
Can someone clue me in as to what is meant by "electrically joined at both ends" which appears in the first paragraph of 310.4(A)? What exactly does that mean?
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IMO it mean exactly what it says, electrically joined even if not physically joined.

I not going to bother arguing this one any further.
 
FWIW..
I recently installed a UL listed inline exhaust fan assembly. The intructions for this unit specifically recommend this wiring method (2-SPST switches or timers wired in parrallel from the same circuit).

For the sake of argument.... if this wiring method violates code, do I not also violate code by failing to install in the method recommended by the intstructions for the listed device?
 
pbeasley said:
do I not also violate code by failing to install in the method recommended by the intstructions for the listed device?
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Only instructions that are included with the listing or labeling are subject to 110.3(B).
 
iwire said:
I not going to bother arguing this one any further.
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I understand.:wink:

But just for the sake of discussion and the benefit of others:

After some further thought, I am agreeing with Bob wholeheartedly. But what this leads too is that the code wording in 310.4 is completely messed up when taken literally. For example, what about the diagram below? It seems the Code language leads to some absurdities if "electrically connected" is taken literally.

1Pictu3.jpg


I can think of plenty of everyday wiring arrangements which literally violate 310.4.

Somebody needs to make me the king of the NFPA.
 
crossman said:
Somebody needs to make me the king of the NFPA.
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I take that back. After looking again at the CEE threads, and thinking about other disagreements on the forum, it is freaking hard to write text which conveys what was intended for every real-world installation out there.

My hat is off to the CMPs for giving it a valiant effort.
 
crossman said:
I take that back. After looking again at the CEE threads, and thinking about other disagreements on the forum, it is hard to write text which conveys what was intended for every real-world installation out there.
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I will say yes to that as well.

Trying to write a code section that is at all concise yet can cover everything from a tar paper fishing shack to a nuclear plant and everything in between has got to be tough enough then add the manufacturers with certain agendas and it has got to be darn near imposable.
 
480sparky said:
Wouldn't it just be cheaper to run them to the coil of a relay that controls the power to the unit? 310.4 Ex. 2.
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Yeah, but anybody could do that. :wink:

Roger
 
iwire said:
Trying to write a code section that is at all concise yet can cover everything from a tar paper fishing shack to a nuclear plant and everything in between has got to be tough enough then add the manufacturers with certain agendas and it has got to be darn near imposable.
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:confused:

Manufacturers don't exert any influence on the code making process.



























;)
 
Honestly, a literal interpretation of 310.4 means that 85% of all conductors we ever install should be 1/0 or larger. <copper.org begans salivating through an evil grin>
 
crossman said:
Honestly, a literal interpretation of 310.4 means that 85% of all conductors we ever install should be 1/0 or larger. <copper.org begans salivating through an evil grin>
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Hopefully they are not listening. :grin:
 
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