Reverse feeding of a main breaker.

[jdennehy]

Hope fully picture is attached. Came across install today with main feeders terminated on lugs at bottom of panel with 250A main breaker installed. Electrician than wired primary side of 75Kva trans former from line side of main breaker. Looked up listing of Schneider Power Pact JG250A breaker and it can be revers feed if is not listed with line and load.

From a safety perspective this is an unsafe installation especially without labeling.

Are they any other NEC violations that I am overlooking.?

 

[jim dungar]

From a safety perspective this is an unsafe installation especially without labeling.

Are they any other NEC violations that I am overlooking.?

This has been a standard construction for Square D panelboards for at least 50yrs.

There is absolutely no NEC violation.

 

[jdennehy]

Jim,

Very familiar with Square D construction and it is a standard panel. My concern is with out any labeling a person could walk up and shut off 250A main and expect to find internal guts dead. But in this case the guts are still live due to the feeders bottom feeding the lugs that were field installed.

 

[iwire]

Still no NEC or listing issue.

How do you know the lugs were field installed?

We get MLO panels with sub feed breakers often.

 

[infinity]

The only issue I see is the lack of labeling for the 3 pole CB. The fact that it's bottom fed may be confusing but is not an NEC violation.

 

[Dennis Alwon]

The panel mounted on its side is a violation. :grin: I'll assume your picture is just oriented incorrectly.

 

[jdennehy]

My issue on this was from a safety perspective.
There is a certain criteria manufacturers have to meet to have a breaker listed for reverse feed.
(1) breaker is bolted in place
(2) does not have a removable trip unit.
(3) Not labeled with Line & Load.

Trying to determine if line & load is labeld on the main breaker. If that labeling exist than the installation violates the listing of the manufacturer, which will pertain to NEC 110.3 (B).

Too answer Iwire question I am making an assumption that the lugs were field installed.

 

[jdennehy]

The panel mounted on its side is a violation. :grin: I'll assume your picture is just oriented incorrectly.

A little humor is good.

Just wanted to have you guys work a little harder.

Appreciate everyones insight.

 

[jim dungar]

Trying to determine if line & load is labeld on the main breaker. If that labeling exist than the installation violates the listing of the manufacturer, which will pertain to NEC 110.3 (B).

The breaker is being applied per its UL Listing.
The Line and Load markings would be easily visible in your photo if they existed.
Is this a main breaker with feed-thru lugs, in which case turning off the breaker would de-energize the guts, but not the breaker lugs? Or, is it a Main Lug panel with a 'sub-feed breaker' in which case turning off the breaker leaves the panel guts energized?

Your picture looks like the breaker is at the top of the panel.

 

[hillbilly1]

The Blue box has lots of panels set up like this, they feed a transformer from the bottom breaker. It is a manufactured assembly.

 

[jdennehy]

The breaker is being applied per its UL Listing.
The Line and Load markings would be easily visible in your photo if they existed.
Is this a main breaker with feed-thru lugs, in which case turning off the breaker would de-energize the guts, but not the breaker lugs? Or, is it a Main Lug panel with a 'sub-feed breaker' in which case turning off the breaker leaves the panel guts energized?

Your picture looks like the breaker is at the top of the panel.

Jim,

I took this a panel shipped with a main breaker. Not sure if panel shipped with lugs at the bottom. Electrican brought main feeders in and terminated them on lugs at the bottom. They utilized what I would have assumed is the main breaker to feed a transformer that is not picture. To answer your question turning off the assumed main breaker will leave the internal panel guts energized.

 

[iwire]

Jim,

I took this a panel shipped with a main breaker. Not sure if panel shipped with lugs at the bottom. Electrican brought main feeders in and terminated them on lugs at the bottom. They utilized what I would have assumed is the main breaker to feed a transformer that is not picture. To answer your question turning off the assumed main breaker will leave the internal panel guts energized.

What you describe is a fairly common installation for us.

Is the breaker at the top of the panel labeled 'Main' if so that would be wrong but other than that there is no problem.

 

[jim dungar]

Jim,

I took this a panel shipped with a main breaker.

As Iwire said, if there is no label identifying it as a Main, it is simply a 'sub-feed' breaker. A 150A breaker, that takes 6 spaces, is the largest branch breaker that can plug-on to the bus in this panel, so they have a separately mounted branch that can go up to 200A (in fact some panels can have two such branches).