Electrical Services

[sarsenault]

I have a unique situation on military property which has a dwelling (120/240V, 100A, single-phase) fed via a 2-pole CB in the Main Dist. which feeds other loads. From the CB, the service goes to a weatherhead and overhead via AL, triplex service drop conductors. Then it goes underground to the dwelling. However, on a triplex, there are only two insulated phase conductors and a bare neutral.

Question: Since the dwelling loadcenter is considered a subpanel of the MDP, doesn't that overhead triplex, bare neutral running overhead to the dwelling have to be insulated?

 

[physis]

Re: Electrical Services

310.2(A) Good thing that's there.

Conductors shall be insulated.

Ex. Where covered or bare conductors are specifically permitted elsewhere in this code.

I feel like I bought a movie ticket and they wouldn't let me in.


I thought I'd be able to find something, but I can't.

 

[thinfool]

Re: Electrical Services

You may have to work with what you have. If this is a US Military installation(or any US Govt property)it is exempt from the NEC.

The guy who put it in probly knew that...possibly he was even following the directions of a PE who was working for the military.

You might be able to get the current 'powers that be' to let you upgrade to a code compliant installation. Many govt jobs now refer to the NEC as a minimum standard...but such has not always been the case.

As I understand it...NEC exemptions currently include:
Railroads
Powerhouses
Federal Govt Installations.

 

[George Stolz]

Re: Electrical Services

Originally posted by sarsenault:
Question: Since the dwelling loadcenter is considered a subpanel of the MDP, doesn't that overhead triplex, bare neutral running overhead to the dwelling have to be insulated?

Not according to 225.4. Follow the grounding connections prescribed in 250.32, and all should be okay, I'd think.

 

[charlie]

Re: Electrical Services

As I understand it...NEC exemptions currently include:
Railroads
Powerhouses
Federal Govt Installations

Actually 90.2(B) does not exempt the government from being covered by the NEC. However, the government would have to adopt the NEC in order for it to be required. As far as I know, the federal government has not adopted the NEC but, in most cases, has voluntarily decided to follow it.

 

[physis]

Re: Electrical Services

I think it's sort of nifty that when dealing with the military, the military is the AHJ.

 

[charlie]

Re: Electrical Services

Just like dealing with the state.

 

[physis]

Re: Electrical Services

And the City.

 

[mc5w]

Re: Electrical Services

If both the away from building CB and the panel inside of the building are grounded as service equipment then the nuetral in between can be bare. Same for feeders running from 1 building to another provided that there are no parallel paths ( such as underground metal pipes ) and no service ground fault protection is required.

If service ground fault protection is required ( such as on 277Y480 volts ), then youmusy use an insulated neutral, a separate equipment ground, and the panel inside of the building has to be wired as a feeder panel.