Do exterior main disconnect switches need OC protection?

[david luchini]

There seems to be a lot of different 230.91's going around Mine is 2014, reads: "The service overcurrent device shall be an integral part of the service disconnecting means or shall be located immediately adjacent thereto."

What does yours say?

That, plus where fuses are used as the service ocpd the disconnecting means shall be on the supply side of the fuses.

 

[electrofelon]

That, plus where fuses are used as the service ocpd the disconnecting means shall be on the supply side of the fuses.

Ahh ok ,so they did change it. I have been procrastinating getting my 2017, bad kitty!

 

[kwired]

There is an exception allowing metering equipment to be neutral bonded after the service disconnect. I dont remember exactly what it says without looking.

So if I have a "meter disconnect switch" that is a fused disco, can I still elect to call that a meter disconnect switch and not a service disco?

Maybe, but POCO's typically will want to lock that enclosure to prevent theft of service, then the overcurrent protection becomes non accessible and not in compliance with NEC allowing it to be the service disconnecting means, for this reason most POCO's will require it to be a non fused switch, they don't want to be called out in the middle of the night to change those fuses that blew because of a customer use issue

That, plus where fuses are used as the service ocpd the disconnecting means shall be on the supply side of the fuses.

That wording was added to that section in 2017. Requirement still existed before 2017 (for most instances as cartridge fuses which is mentioned is pretty common) in 240.40 and still is required in 240.40 in 2017 as well.

 

[pv_n00b]

Hi,

Consider the situation where the service conductors enter a point in a residence that is not adjacent to the main circuit breaker panel. I understand that a main disconnecting means will be required along the service conductors at a point before they enter the home. My question is, will this disconnecting means need to also incorporate OC protection if it has a manual disconnect lever? I am also assuming that the circuit breaker panel inside the home already has OC protection. Thanks in advance.

NEC 230.70(A) covers location. The service disconnect has to be readily accessible and outside the building or inside nearest the point of entrance of the service conductors. NEC 230.91 requires that the service OCPD be a part of the disconnect, or immediately adjacent to it, which means right next to it.

This is a part of the code that I have found tends to have a lot of local modifications and also get's mixed up with utility standards. There can be multiple disconnects in the service entrance conductors that provide various functions but may not be the service disconnecting means. One disconnect has to be identified as the service disconnecting means and it has to comply with the NEC. The others may comply with utility standards such as ones that isolate the meter to provide a cold sequence or may be in an MSP which would then not be the service disconnecting means.