Neutral required with fire pump disconnect?

[cppoly]

Is a neutral required with a fire pump disconnect and where would I find this requirement?

 

[gadfly56]

Is a neutral required with a fire pump disconnect and where would I find this requirement?

Most of the time you don't break the neutral at a disconnect; there's no reason to. Most fire pumps are 3-phase and the ones we typically installed did not require a neutral but did include an EGC.

 

[cppoly]

Since it's a service switch it's required to have a neutral connection and a neutral conductor?

 

[texie]

Is a neutral required with a fire pump disconnect and where would I find this requirement?

With a fire pump service fed from a grounded system, the grounded conductor absolutely must be brought to the service disconnect and bonded per 250.24(C). Depending on your design, the fire pump controller is likely the service. In the unusual case where the fire pump controller is fed from a feeder the the grounded conductor would have to be brought to the service disconnect for that feeder.

 

[cppoly]

How would you size this neutral conductor for a fire pump disconnect even though it's not used? Sized to match the circuit conductors or sized to match 250.66 table?

 

[texie]

How would you size this neutral conductor for a fire pump disconnect even though it's not used? Sized to match the circuit conductors or sized to match 250.66 table?

For the 2011 NEC, yes, it would be 250.66 or in the 2014 edition it would be 250.102(C)(1). Same end result.