Commercial Panel

Few pictures here for Master Electricians to comment;

This is a 125 amp 3-phase panel being installed.

This is the tub rating label

This is a picture of the Neutral Bar and the electricians are telling me, because of the egg shaped holes, two neutrals can be installed in those ports, and only one in the round bigger holes.


This is a grounding bar not yet installed on the panel, which comes with the guts of the panel.
Same applies here, two grounding wirings can be installed in the elongated holes and only one in the round holes.

Maybe Paul can chime in or others that know more about this than I do.


Hey Fella,

There are holes that do allow more than a single conductor. I would have to see the cover and the listing of the panel to be 100% sure. Just because the holes are larger does not always mean they are that way to facilitate more than (1) one conductor. You simply have to look at the listing of the panelboard and the labeling within the panelboard or on the cover. I dont see any cover shots so you would have to verify it from that standpoint.

Now the issue comes up with this is unless I know otherwise or a manufacturer ( not an electrician ) tells me otherwise I have to assume 408.41 as the golden rule here.

Now…notice the Exception to this rule…

**408.41 Grounded Conductor Terminations.
**Each grounded conductor shall terminate within the panelboardin an individual terminal that is not also used for another

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.

So make them show you the information allowing more than (1) grounded conductor per terminal. Otherwise stand your ground…get it…stand your ground…you need to remain grounded…get it…remain grounded…I am so well bonded it aint arcing funny…get it…arcing funny…!

Also remember that same label will tell you how many EGC’s can share a terminal as well.

Also I might add…since this appears to be a commercial application. Make sure they dont have any of that NM Cable above any suspended ceilings…:wink:

Now I am just saying this…as I would normally say it. I would love to see the calculated load on that panel since it appears to be chock a block full of circuit breakers. Yes, some may be empty and yes loads may be small but as a electrical plans examiner I would love to sink my mathmatics into the calculated load in that 125A panel…But alas, the 125A will limit the load.

Oh…and another thought…what is the type of construction on this project…lets hope it is not 1A or B and 2A or B rated construction…they would have to loose the NM Cable all together.

Thanks Paul, that was a lot of help.
I am sure they know what they are doing, just trying to educate myself as to what I am looking at sometimes.

Thanks again:):smiley:

I am here for ya brother…you know that. Just remember when a guy says a panel is approved for (2) grounded conductors under a single lug, ask for proof of this. The exception allows for parallel conductors in lugs rated as such but anything probably not gonna happen unless they can show you this in written form on the equipment.

You might want to elaborate on this one.
This building is less than three stories, Romex is used throughout except a couple of rooms that are place of assembly where they use all MC cable.
I believe the lights are all wired with MC to a junction box at the drywall ceiling above.
They just started installing the suspended ceilings so I will check when I go back.

Thanks. :):smiley:

They are fine with MC as long as they keep it within the areas of assembly. The issue is in the nonrated construction areas where NM Cable is fine except where it may run above a dropped or suspended ceiling. Now, if the construction rating is a type I or II then NM Cable would not be allowed anywhere in the construction.

Chances are it is not type I or II construction so as long as they dont install the NM Cable above dropped or suspended ceilings or in the assembly areas they shoud be fine.