Empty 200a commercial service

[danickstr]

so if the owner wants me to put an empty 200a service 120/240 Sph, should I go ahead and pull a full size neutral to anticipate the possible harmonic feedback if the new tenant puts in a bunch of monitors? Or just take it down 2 sizes?

 

[iwire]

Harmonics are not an issue to worry about for the neutral of a 120/240 single phase service.

 

[don_resqcapt19]

Or just take it down 2 sizes?

What basis is there for reducing the neutral 2 sizes? Without a load calculation I see no way that you would be permitted to reduce the size of the grounded conductor.
Don

 

[danickstr]

Thanks for replies.

 

[mhulbert]

What do some of you out there do on residential 120/240 services in regards to the neutral. I have heard the 2 sizes idea, but I usually use a neutral the same size as the phase conductors. 99% of the time, it's a waste of material, but I odn't have any sound reasoning to go smaller, especially with something like the neutral.

Just curious what standard practice is out there?

Mike

 

[Pierre C Belarge]

See 250.24(C)(1) for one way of sizing the Grounded Service conductor.

 

[bphgravity]

What do some of you out there do on residential 120/240 services in regards to the neutral. I have heard the 2 sizes idea, but I usually use a neutral the same size as the phase conductors. 99% of the time, it's a waste of material, but I odn't have any sound reasoning to go smaller, especially with something like the neutral...

Mike

Considering that several loads that will be typcially found in dwelling occupacny have a reduced and/or no nutral load, reducing the neutral conductor size is permitted. However, there are consequences to this code allowance.

Issues that need to be considered are future loads that will be carried on the neutral and the increased of impedance of the fault current path.