Neutral Routed Through MCB

Status
Not open for further replies.
T

The Apprentice

Member
I have an industrial customer with an existing control panel with a 120VAC feed. He wants me to replace an existing 15A/1P main circuit breaker with a new 15A/2P breaker, remove the neutral from the existing power distribution block, route the neutral through the new main breaker, then reconnect to the PDB.

I haven't been able to find an article in the NEC that either prohibits or even addresses this practice.

Can anyone help?

I apologize in advance if this issue has been covered, but I couldn't find anything.

Thanks!
 
Re: Neutral Routed Through MCB

If I understand the question correctly, you are being asked to route the grounded conductor thru the same overcurrent protection device as the ungrounded conductor. 240.22 allow this.
The only violation I can think of is that, if this piece of equipment is listed and labeled (UL, etc), you would be altering a piece of listed equipment.
 
Re: Neutral Routed Through MCB

Switching the neutral is allowed if the line is switch simultaneously as what you would be doing with your 2p common trip breaker.
 
Re: Neutral Routed Through MCB

Depending on what this panel serves, sometimes it is required to switch the neutral with the hots.
 
Re: Neutral Routed Through MCB

I would not switch the grounded conductor with one of the poles of the 2-pole breaker unless there was a good reason to do so.

Yes, generally it is recognized by NEC if it is a common trip bkr. in which all poles operate simultaneously. But there is very seldom a good reason to do this & I like the K.I.S.S. principle.

Only case I can think of is hazardous location for gasoline where NEC requires "switched neutral" breakers for circuits to dispensing pumps.
 
Re: Neutral Routed Through MCB

I'd like to thank everyone for their help on this issue. Although it's apparently not prohibited by code, I'm still going to recommend to the customer that we don't do this, simply because there's no compelling reason.

Thanks again everyone!
 
Re: Neutral Routed Through MCB

Originally posted by The Apprentice:
I have an industrial customer with an existing control panel with a 120VAC feed. He wants me to replace an existing 15A/1P main circuit breaker with a new 15A/2P breaker, remove the neutral from the existing power distribution block, route the neutral through the new main breaker, then reconnect to the PDB.
Click to expand...
I'd like to know what is meant by "control panel", what is this "main breaker", and how would the neutral feed get into the breaker.

I envision a breaker-mounting base with input terminals, like a breaker/disconnect, or a special-order breaker with input and output terminals.

I'd especially like to know why the customer wants the neutral protected? :confused:
 
Re: Neutral Routed Through MCB

Is the neutral grounded? If it is would that not be an issue because the MCB would be opening up a grounded conductor?
 
Status
Not open for further replies.
Top