208 three phase question

[overmyhead]

when is it required to install a neutral conductor for new 208 three phase equipment? I would like to skip the neutral in this case as it is a 600 foot underground pull, but I don't want to be out of compliance.

 

[augie47]

If thye system is grounded, a neutral is required to be installed to the service disconnect.
After the service disconnect, the neutral is only required to be installed when needed

 

[Dennis Alwon]

I agree with Gus that the neutral is needed at the service but not at a subpanel if not used. If the owners insist on a neutral for future use then it can be sized as small as the egc but not any smaller.

 

[chris kennedy]

Your code references for the above are 250.24 (C) and (C)(1).

 

[Jraef]

The key point is the "if not used" part. If you are feeding a panelboard where there will be 1 pole breakers for 120V loads, you must pull the neutral.

 

[Dennis Alwon]

Your code references for the above are 250.24 (C) and (C)(1).

Actually the code reference for feeders is 215.2(A)(1)- the paragraph after the exception. but you are correct for services.

The size of the feeder circuit grounded conductor shall not be smaller than that required by 250.122, except that 250.122(F) shall not apply where grounded conductors are run in parallel.

 

[PhaseShift]

If the owners insist on a neutral for future use then it can be sized as small as the egc but not any smaller.

Is this typically the approach taken when a panel is installed with no neutral loads at present, however there may be the possibility of neutral loads in the future.

If presnent neutral loads are just receptacles and lighting and you balance the circuits then can you sill use 250.122 for minimum size of neutral?

 

[Dennis Alwon]

Is this typically the approach taken when a panel is installed with no neutral loads at present, however there may be the possibility of neutral loads in the future.

If presnent neutral loads are just receptacles and lighting and you balance the circuits then can you sill use 250.122 for minimum size of neutral?

Is that not what I said above???

 

[overmyhead]

thanks guys.

 

[kwired]

No neutral no 120 volt receptacles, lights or control circuits, unless you install a transformer to supply those items.

 

[Chamuit]

I have installed load centers without a neutral and come back and found 120V circuits installed in them. Just a thought.

 

[Dennis Alwon]

Sounds like the op is just feeding a piece of 3 phase equipment 600 feet away underground. Sounds like a separate building or structure-- I would like to know more.

 

[mbeatty]

Sounds like the op is just feeding a piece of 3 phase equipment 600 feet away underground. Sounds like a separate building or structure-- I would like to know more.

I agree. More info is needed.
Regards,
Mark