Isolation

[David C. Macy]

Are the grounds & nuetrals properly isolated in the photo below. They are on seperate parts of the bar but the bar is connected.

This is a Auxilary panel and not the main distribution panel.



Thanks

[Jeffrey R. Pope]

Originally Posted by dmacy

They are on seperate parts of the bar but the bar is connected.

You answered your own question - NO.

The neutrals must be isolated from the enclosure. The grounds must be bonded to the enclosure.

You cannot meet these requirements if the "bar is connected."

[wsiegel]

Bump

[David C. Macy]

Originally Posted by jpope

You answered your own question - NO.

The neutrals must be isolated from the enclosure. The grounds must be bonded to the enclosure.

You cannot meet these requirements if the "bar is connected."

Thanks

I usually know the answer but I like to make sure before I submit the report.

This was a pre list & I want to make sure there is no second guessing on my end.

Thanks Jeff I value you expert opinion.

[Brian E. Kelly]

[David C. Macy]

What is the hazard of bonding the grounds & nuetrals?

[mthomas2]

Q. Given the physical and electrical nature of the connection between those two panels, what is the difference between this and a "split bus" service panel where with the lighting section's bus is fed via a breaker? Is the second panel in this set up considered a "distribution" panel, or part of the service panel?

[Jeffrey R. Pope]

Originally Posted by dmacy

What is the hazard of bonding the grounds & nuetrals?

A parallel path of current which may energize panel boxes, conduit, etc. etc.

[Jeffrey R. Pope]

Originally Posted by mthomas2

Q. Given the physical and electrical nature of the connection between those two panels, what is the difference between this and a "split bus" service panel where with the lighting section's bus is fed via a breaker? Is the second panel in this set up considered a "distribution" panel, or part of the service panel?

The split bus would be considered within, or part of, the service equipment. . .

[Greg Fretwell]

The operative language is "Objectionable Current over Grounding Conductors". You don't ever want circuit current flowing in any grounding conductor, including the main bonding jumper.
That means that even if this is the main panel, you don't want white wires on supplimental buses that are screwed directly to the enclosure. Their path to the transformer X0 is through the bonding jumper or green screw

[Michael Martin]

Originally Posted by Greg Fretwell

The operative language is "Objectionable Current over Grounding Conductors". You don't ever want circuit current flowing in any grounding conductor, including the main bonding jumper.
That means that even if this is the main panel, you don't want white wires on supplimental buses that are screwed directly to the enclosure. Their path to the transformer X0 is through the bonding jumper or green screw

I thought that in a main panel, if you happen to have two bonded grounding/neutral buses, it doesn't matter where the grounded and grounding conductors go (i.e., that you could mix them on the two buses).

[Greg Fretwell]

If the grounding bus is simply screwed to the can you are sending circuit current through the enclosure. That in not correct.

[Michael Martin]

Okay, I'm trying to understand. Assume that there is only one bus in the main panel, and that both grounded and grounding conductors are attached to that bus. Isn't that bus bonded to the enclosure? If so, doesn't that mean that return current, even though it is flowing back through the neutral line to the center tap on the transformer secondary, is also present on the panel? Or rather does the fact that it is flowing back to the tap mean that there is no current on the panel?

Doesn't the green screw bond the bus to the enclosure?

[sparksnmore]

Originally Posted by Michael Martin

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Doesn't the green screw bond the bus to the enclosure?

I think maybe you're confusing "main panel" and "sub panel"

[Greg Fretwell]

The point is you are never supposed to impose circuit current on the enclosure ... period. If this is not part of the neutral bus(s) it should not have white wires on it. The main bonding jumper (green screw) is not listed as a circuit conductor.