240.20

[darrin]

Article 240.20 states that Overcurrent Protection Devices are to be located in series with each ungrounded conductor. Is there any article or reason that the overcurrent protection device cannot be located in the neutral or grounded conductor as well. I have a 480v-120v, single phase industrial control transformer that I typically provide overcurrent protect in the ungrounded conductor on the secondary side of the transformer. The customer also wants me to have overcurrent protection in the neutral or grounded conductor on the secondary side as well, basically a double pole breaker, one pole for the ungrounded conductor and one pole for the grounded conductor. I tried to explain to him that it is not necessary and that I thought it wasn't permissable by code, however I am finding out that there is no specific Code article that I can find that actually prohibits overcurrent protection in the grounded or neutral conductor. Thoughts Comments??

 

[jim dungar]

If the ungrounded conductor opens at the same time as the grounded conductor does (i.e. a 2 pole breaker) it is permissable to have overcurrent protection in the grounded conductor.

 

[cadpoint]

....
The customer also wants me to have overcurrent protection in the neutral or grounded conductor on the secondary side as well, basically a double pole breaker, one pole for the ungrounded conductor and one pole for the grounded conductor. ...

You can go to your client after you visit 240.90 240.90 (B)(1) & (2)...

Er is it like what that other guy says, I think that what You said

 

[don_resqcapt19]

See 240.22

 

[rcarroll]

Disconnecting the grounded conductor, if any, is required for fuel dispensing. 514.11

 

[charlie b]

The customer also wants me to have overcurrent protection in the neutral or grounded conductor on the secondary side as well. . . .

I agree with the other replies. But let me add that you will not be providing "overcurrent protection" in the neutral, or at least not independently from that in the ungrounded conductors. There is no scenario in which the neutral wire can experience an overcurrent condition, without the ungrounded wire also experiencing the same overcurrent condition. The reverse is not true. You can have overcurrent in the ungrounded, and no current in the neutral, if there is a short circuit internal to a load.