Neutral Connection Necessary?

[muhandas]

A commercial distribution system consists of a main disconnect, a panel with appropriately sized overcurrent protection, and 3-phase, 4 wires distributed to several motor controllers, each with its own delta-connected transformer, feeding separate appliances. Thus, there is no electrical connection for the neutral conductor coming from the panelboard.
Since the motor controllers are pre-assembled, off-the-shelf products, each comes comes with a "neutral block" should a neutral connection become necessary for the application.
In this case, removing these blocks makes the routing of the sizeable phase conductors easier within the individual motor controllers.
Two questions:
1) Engineering consideration aside, does the Code permit terminating the neutral conductor before it enters the motor controllers, or must the neutral conductor be connected to the "neutral block" within the motor controller (although there will be no further electrical connections made)?
2. Should a neutral conductor be needed for future needs, does the Code allow reducing the size of the neutral conductor to smaller than the existing phase conductors?
Many thanks for your help.
Heinz

 

[bphgravity]

Re: Neutral Connection Necessary?

1. If no grounded (neutral) conductor is needed for the utilization equipment, then it is not required to be installed.

2. Yes, conductors need only be sized for the maximum load that they will carry, save a few exceptions.

 

[charlie b]

Re: Neutral Connection Necessary?

You did not even need to run 4-wire to the motor controllers in the first place. I am presuming you mean 4 wires plus a fifth ground wire. All you needed was 3 ungrounded (phase) wires and one ground wire.

But if there is a neutral wire in the feeder or branch circuit, and if you want to terminate it some place other than the controller's neutral terminal, then where do you propose to terminate it? My question would be whether it is acceptable to leave it un-terminated at both ends (capped and labeled, as appropriate).

 

[muhandas]

Re: Neutral Connection Necessary?

Thanks Bryan and Charlie. These were also my gut feelings but I felt insecure and wanted some confirmation from you experts. I couldn't find anything in the Code that would not allow this.
The Neutral could be terminated (capped and marked) at or within the panelboard. If you think that would be a problem please holler.
Tx again and a Happy New Year to all.
Heinz