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Joined: Jul 2004
Posts: 9,687
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G
Member
I saw a panel the other day that still has me scratching my head. It is an old GE with 8 breaker slots total. The buses are split left and right and the pair is fed or feeds at the top. First concern. If this panel is installed the way the labels are right side up, the top breaker on on when the handle is down so to be legal it has to be mounted sideways. This can be set up either as a main breaker panel or MLO on the label.
The one I saw was MLO with two 240v breakers and two 120v 20a breakers, (one on each ungrounded conductor because of the bus layout). So far so good other than the panel orientation.
Now the real question. There was no neutral bus, only a ground bar, attached to the can. The two neutrals were under a wirenut, connected to a white 12ga running along with the feeder from the main panel.
I know it us ugly but is it legal?
The neutral is not regrounded and 408.41 seems to be satisfied.

Quote
Grounded Conductor Terminations. Each grounded
conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.
Exception: Grounded conductors of circuits with parallel conductors
shall be permitted to terminate in a single terminal if the terminal is
identified for connection of more than one conductor.


I thought the catch might be "terminal" but 110.14(A) doesn't preclude a "splice".

Quote
A) Terminals. Connection of conductors to terminal parts
shall ensure a thoroughly good connection without damaging
the conductors and shall be made by means of pressure
connectors (including set-screw type), solder lugs, or splices to
flexible leads. Connection by means of wire-binding screws or
studs and nuts that have upturned lugs or the equivalent shall
be permitted for 10 AWG or smaller conductors.

What am I missing?


Greg Fretwell
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Joined: Aug 2011
Posts: 33
Likes: 1
G
Member
Don't have code book nearby. Does the grounded conductor need to be at least the same gauge as the ungrounded conductors (which I assume are bigger than #12)?

Joined: Jul 2004
Posts: 9,687
Likes: 10
G
Member
Originally Posted by grich
Don't have code book nearby. Does the grounded conductor need to be at least the same gauge as the ungrounded conductors (which I assume are bigger than #12)?

I don't believe that is true. In fact computer room panels didn't even have a neutral brought to them because they did not have any line to neutral load. They used that bus for the isolated ground.

I do see this
Quote
220.61 Feeder or Service Neutral Load.
(A) Basic Calculation. The feeder or service neutral load shall
be the maximum unbalance of the load determined by this article. The maximum unbalanced load shall be the maximum net
calculated load between the neutral conductor and any one
ungrounded conductor.

Since the max possible load is 20a, 12ga should be sufficient. All the other loads are line to line.
I understand there is a lot of possibility for what ifs but I was told a long time ago you have to inspect what is there, not what some installer might do later. In that case it was a 400a panel with 250a fuses in it and conductors sized to those fuses. (350 Kcmil al)


Greg Fretwell

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