Ok - check me on this one please - Sub panel in a garage, fed with two ungrounded and one grounded conductor through a plastic (liquidtight?) conduit. No other connections between the buildings. Neutrals and grounds bonded in the sub panel. The panel has a separate egc that runs outside the garage to a ground rod. The feeder is three individual conductors not sheathed in a jacket as they run from the main panel to the underground conduit. If I’m reading nec 250.32 right, the panel is ok. What about the unsheathed conductors? Gentlemen, your thoughts please--
The neutral and ground cannot be tied together in a sub panel. The feed wiring outside should be rated for underground/outside use or in sum type of better sealed conduit. If those are just single wires running out the top of the panel, they should be shielded somehow, such as a flex metal conduit.
Also I would note that the wire size is not big enough feeding the panel if all breakers would be used. Some areas of the country actually have a minimum size of wire feed and ground requirements on sub panels, it all depends on who is enforcing.
Neutrals and grounds can be connected in a sub panel if it is in a separate building with no other connections between the buildings. The feeder is appropriate - 8awg fed by a 40-amp breaker in the main panel. The feeder was in a conduit as it ran between the buildings (underground), but not in the basement.
Ground bar needs bonded to panel, it doesn’t look like it is from here. Neutrals should be isolated from panel. Building needs a disconnect. The Grounding Electrode Conductor (white wire) appears undersized.
As far as feed wire size, depends on size of breaker feeding it.
It depends on the code cycle that this was installed under. Earlier versions of the NEC did not require a separate EGC within the feeder if there were no other metallic paths between the separate structures. Are you saying that they pulled conductors into the panel without a raceway?
Yes Robert - the conductors ran from the panel to the junction box / conduit without a raceway. If I am reading it right, this panel is in compliance with the 2005 NEC (250.32 (B)(2). The conductors are the problem, right?
You are right Robert - conductors were not attached to all of the breakers.
Chris - the feeder was protected in the main, but there was no main disconnect in the garage for the sub. The bonding screw was not attached to the neutral/ground bus.
Excellent responses. Thanks to all.
After looking at the photo’s again I must say that someone had little idea of what they were doing. For one they attached the bonding strip in the AC cable to the ground bus. They ran single conductors without a raceway. They didn’t bond the neutral/EGC bus to the enclosure.
One thing that they did half right is that this setup requires a grounding electrode system, which they installed with the ground rod and bare GEC. Depending on when this was installed two ground rods may have been required.
