Can someone explain this to me?

On another post in relation to double tapped neutrals, parallel conductors was mentioned (see below). Can someone explain to me what is meant by that and how I could identify it?

*Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor. *

Where is that exception located? Are you asking a general question about what are parallel conductors?

Yes. I am asking about parallel conductors. The exception is part of the NEC that says that only one neutral can be located under a screw on the neutral buss in the panel but it listed an exception if it is with parallel conductors (or circuits). I am trying to figure out what they are and how I could identify them by looking in the panel.

OK, parallel conductors allow you to connect multiple conductors on both ends to create, in affect, one larger conductor. This is usually done in commercial work where the ampacities of circuits exceed 400 amps and it’s easier or cheaper to install multiple sets of parallel conductors instead of installing one set of larger conductors.

The exception is pointing out that if you had a lug listed for more than one conductor it can be used to terminate two neutral conductors which are generally limited to one conductor per hole. Here’s a few photo’s:

Lugs listed for one or two conductors:

Parallel conductor terminations in a 500KVA transformer:

I hope this helps.


Series and Parallel circuits

Panel bars.jpg

Thanks for the information. I do understand parallel circuits in DC but it did not make sense in AC current. It doesn’t look like I will run into this much in residential inspections.