310.4 Conductors in Parallel (2005 NEC)

[new_pe]

Hello,

I have a question regarding conductors in parallel, specifically taps to these conductors. The following is an excerpt from the 2005 NEC Handbook:

310.4 Conductors in Parallel

Conductors connected in parallel are considered a single conductor with a total cross-sectional area of all conductors in parallel. Therefore, if individual conductors are tapped from conductors in parallel, the tap connection must include all the conductors in parallel for that particular phase. Tapping into only one of the parallel conductors results in unbalanced distribution of tap load current between parallel conductors. This unbalance results in one of the conductors carrying more than its share of the load, which can cause overheating and conductor insulation failure.

So my question is this... Since this is just the "handbook" notes and not the actual code, what part of the codes tells us directly that we have to tap all conductors of the parallel conductor set? I've searched and searched and this is the best I can come up with but I'm not sure it'll stick because its not in the code, its in the handbook.

Thanks

 

[iwire]

what part of the codes tells us directly that we have to tap all conductors of the parallel conductor set?

The fact that all conductors are required to have the same characteristics does it for me.

 

[roger]

We really wouldn't need a code to tell us this would we, it would be basic physics in trying to keep things equal on all current paths.

Roger

 

[qcroanoke]

We really wouldn't need a code to tell us this would we, it would be basic physics in trying to keep things equal on all current paths.

Roger

Roger that!

 

[rbalex]

The fact that all conductors are required to have the same characteristics does it for me.

Specifically 310.4(B)(5); each conductor must be terminated in the same manner and taps are terminations.

 

[iwire]

Specifically 310.4(B)(5); each conductor must be terminated in the same manner and taps are terminations.

Are the parallel conductors terminated at a tap? I really would not have called it that if using a connector like a split bolt.

 

[rbalex]

Are the parallel conductors terminated at a tap? I really would not have called it that if using a connector like a split bolt.

Since there is neither formal definition of ?terminated? or its root term in Art 100 nor a particularly relevant definition in Webster?s Collegiate Dictionary, 11th edition, I simply refer to Section 110.14 as a general reference to such concepts where it uses connections, terminations and, to some degree, splices interchangeably depending on context and application, usually within the general idea of "connection.?

 

[new_pe]

Specifically 310.4(B)(5); each conductor must be terminated in the same manner and taps are terminations.

Physics aside (because its obvious to you and I, but somehow not the original electrician) its hard to tell a plant manager they need electrical rework because they say "its been working this way all this time." But show them a code violation and they are much quicker to take action. 310.4(B)(5) is what I was leaning on but wasn't sure all the taps off the conductors in this gutter were considered terminations.

 

[iwire]

Since there is neither formal definition of ?terminated? or its root term in Art 100 nor a particularly relevant definition in Webster?s Collegiate Dictionary, 11th edition, I simply refer to Section 110.14 as a general reference to such concepts where it uses connections, terminations and, to some degree, splices interchangeably depending on context and application, usually within the general idea of "connection.?

FWIW I think each time the NEC uses the word 'termination' it appears to indicate the end of an item not the middle.