Service Neutral Size

[danno1202]

I am doing calculations for a 200 amp service, which will be for off-peak loads only. There is a 25 Kw Electric storage furnace, and a 4.5 Kw water heater. The only 120 volt load will be the furnace fan, and control circuit. I'm coming up with 250, 250 aluminum for the hots, and a #2 service neutral. That #2 seems awfully small but is that correct? Looking for some other opinions. Thanks.

 

[augie47]

Looks Code compliant.

 

[Dennis Alwon]

I am doing calculations for a 200 amp service, which will be for off-peak loads only. There is a 25 Kw Electric storage furnace, and a 4.5 Kw water heater. The only 120 volt load will be the furnace fan, and control circuit. I'm coming up with 250, 250 aluminum for the hots, and a #2 service neutral. That #2 seems awfully small but is that correct? Looking for some other opinions. Thanks.

Your neutral is compliant and can be as small as the grounding electrode conductor based on Table 250.66. Generally a #4 would do the job for a 200 amp service as long as you don't anticipate the need for larger loads.

 

[Dennis Alwon]

Here is the article for the 2014 NEC. Before that use Table 250.66 as I stated above

250.24(C)(1) Sizing for a Single Raceway. The grounded conductorshall not be smaller than specified in Table 250.102(C)(1).

This table is virtually the same as 250.66