backfeeding electrical panel

[jbwhite]

i have not done this reciently, but i have in the past backfeed a perminant electrical panel from a temporary panel.

The situation is this: We have a temporary meter/panel installed for construction. The perminant panel is installed. Several areas of the building have lighting circuits that are complete. The rooms are ready for painting and the painter needs the perminant lights turned on to be able to see what he is doing better.

I ran one #12-3 circuit from the temporary pole to the perminant panel. Connected the neutral wire to the neutral/ground bar at both ends.
put the two hot conductors on breakers at the temp pole, and wirenuted the circits needed from the temp wire to the branch circuit wires that i wanted to have energized.

Is this safe?

 

[charlie b]

Re: backfeeding electrical panel

I don't quite understand the installation. I think you are saying that the permanent panel is being used, just temporarily, as a junction box. You take the branch circuit conductors for the lights that the painters need, disconnect them from their breakers in the permanent panel, and wire nut them to the branch circuit conductors from the temporary panel. Is this right?

If so, I see two unsafe things about it.

First, you should not tie the neutral to the ground at both the temporary panel and the permanent panel. It will cause current to flow in the equipment grounding conductors and the grounding electrode system. This is a violation of 250.24(A)(5).

Secondly, I suspect that there was no administrative control to make sure the temporary connections were removed before the permanent power was connected. That would create a safety hazard, in that an electrician might try to do work in that panel without knowing that there were two sources of power within that panel. I don't know of any specific article that this would violate. But I don't think it is safe.

 

[pierre]

Re: backfeeding electrical panel

Why don't you locate the neutral conductors and the EGCs of the two lighting circuits in the "permanent" panel and terminate them accordingly? then the panel enclosure is only a temporary splice box/enclosure.