1200a service

Status
Not open for further replies.
Tell us more

Tell us more

What is the neutral load according to the service calculations?
What is the service for? (Bank, hospital, pinball arcade, or really huge McMansion)
Not enough information in OP to even guess at answer.
 
Hendrix said:
208-120vac parallel. Should the grounded conductor be the same size as the ungrounded conductors?
Click to expand...

The grounded conductor(s) must be sized for the load and not necessarily the same as the ungrounded conductors. But be aware that in no case can the grounded conductor(s) be smaller than indicated in Table 250.66 even if there is no load calculated load on the grounded conductor. See 250.24(C).
 
texie said:
The grounded conductor(s) must be sized for the load and not necessarily the same as the ungrounded conductors. But be aware that in no case can the grounded conductor(s) be smaller than indicated in Table 250.66 even if there is no load calculated load on the grounded conductor. See 250.24(C).
Click to expand...

That is the correct response based on NEC minimum requirements. Anything beyond that is a design issue, and not a code requirement.

Not sure exactly which section it is but I think there is an informational note stating that it may be desirable to increase the grounded conductor size in cases where high harmonic currents are expectedl. This is just an informational note though and not a requirement.
 
kwired said:
Not sure exactly which section it is but I think there is an informational note stating that it may be desirable to increase the grounded conductor size in cases where high harmonic currents are expectedl. This is just an informational note though and not a requirement.
Click to expand...

I think kwired is referencing the informational notes pertaining to 220.61.
 
texie said:
The grounded conductor(s) must be sized for the load and not necessarily the same as the ungrounded conductors. But be aware that in no case can the grounded conductor(s) be smaller than indicated in Table 250.66 even if there is no load calculated load on the grounded conductor. See 250.24(C).
Click to expand...
I am refering to the "grounded" conductor, not the "grounding" conductor.
 
Hendrix said:
I am refering to the "grounded" conductor, not the "grounding" conductor.
Click to expand...

So am I. See 230.31(C) and 250.24(C). Your OP said service, but the requirements for a feeder would be similar except you would use Table 250.122. I know you think think I'm refering to grounding conductors but you have to remember that the grounded conductor has to carry the fault current just like an EGC.
 
Last edited:
I believe most, if not all, the answers you were given addressed the groundED conductor.
There are correlations between the grounded and grounding conductors.
As noted in 250.24(C) we are reminded that the groundED conductor supplying a servicd can not be smaller than the groundING electrode conductor.
In 215.2 we are advised that the groundED conductor can not be smaller than the equipment groundING conductors for feeders.

Beyond that, and the minimum size parallel rule, the grounded conductor(s) can be sized be Art 220.
 
In most case the neutral- grounded conductor is sized the same as the ungrounded conductor in commercial work
 
Last edited:
Status
Not open for further replies.
Top