Sub Panel - Separation - Isolation

[Matt Faust]

Hi Guys,

I am a Real Estate Inspector in CA.
Thanks for inviting us to post on your board.

I don't know how to post a photo with a url so I'll just explain.

Condo sub panel
Has two bus bars in panel.
BB's are isolated in plastic carriage.
Assumed bonding to metal enclosure via bonding screw, not verified.
However, all EGC's and neutral conductors share one bus bar.
No separation -
No evidence of EGC's being bonded to metal enclosure.
(And if this BB is bonded - then the neutrals are also bonded)

I am calling it improper wiring and recommending a qualified,
state licensed Electrical Contractor.

1. So, am I correct.
2. Also, how dangerous is such a configuration?

Thanks Again
MF -
Home Inspection Service of the West

 

[Dennis Alwon]

If this is truely a sub panel within the same building as the main panel then the neutrals and grounds must be separated. The neutrals and grounds will only be bonded together at the main panel.

 

[infinity]

I agree with Dennis they need to be separate if this is a subpanel. In this case a photo would really help. :smile:

We could help you post a photo if you have one.

Welcome to the forum.

 

[Matt Faust]

1. The main disconnect is at the meter on the exterior of the building.
(with all the other meters)
2. There is no doubt that this is a sub panel.
3. I am fairly proficient where the NEC and residential applications are concerned.
4. I tried to paste the photo as a reply to Jumper - it didn't paste.
5. If anyone has an email I can send it as an attachment - my email is
xxxxxxxxxxxxx- hope I am allowed to post that.
6. Also - how about the potential (no pun intended) danger of this condition?

Thanks - MF

Moderators note: I did remove your email address, you can PM another member or moderator to exchange this info, I would be able to help but it won't be until later tonight.

 

[charlie b]

Also - how about the potential (no pun intended) danger of this condition?

Here is an explanation I wrote up some time back. Let me know if it helps.

Why grounds and neutrals are tied only at the main service, and not at a subpanel.

Reference: NEC article 250.42.

The reasons that there is a difference are (1) That current is always seeking a path back to its source, (2) That current will take every available path, and (3) The main panel is essentially the source, being both the beginning and the end of the line for current flow.

The function of the equipment grounding conductors (EGC), that ones that connect to the ground bar in the panel, is to carry fault current. If a fault occurs with a piece of equipment, such that a hot conductor comes into contact with the case or other external metal part, any person who touches that equipment is going to get a shock. The shock can be enough to kill, but the current will not be high enough to cause the breaker to trip.

However, with the EGC creating a path from the case back to the ground bar, then via the ground screw or bonding jumper to the neutral bar, the current in this path will be high enough to trip the breaker. This will terminate the event before the person can receive a fatal shock. That is why the ground and neutral buses are connected at the main service disconnecting means – to complete the current path from the fault point back to the source. In this context, I am treating the main panel as the "source." Once the current gets to that point, it has nowhere else go.

If you also connect the ground and neutral at a subpanel, then there will be two paths for current to flow back to the source during normal operation. Current will be flowing in the neutral most of the time (unless the loads running at the moment are perfectly balanced among the phases). But with the ground and neutral tied together both at the main panel and at the subpanel, the EGC will be in parallel with the neutral wire. Therefore, the EGC will carry current. This will cause the external metal parts of each and every component that has an EGC to become energized. You could not safely touch anything in the facility.

 

[charlie b]

4. I tried to paste the photo as a reply to Jumper - it didn't paste.

Hit the "Post Reply" button below, and look for a box (it will be below the box you type replies into) labeled, "Manage Attachments." That will bring you to a page from which you can upload a photo from your computer. It will show up in your reply as a thumbnail, but we can click that and get an enlargement. I am attaching a sample photo of mine, just to show you what this process does.

 

[jumper]

here is a picture of the panel in question

 

[luckyshadow]

1) For cripes sake How hard is it to cover the panel when spraying the paint on the walls?
2) How hard is it tie in a small panel like that neatly?
I know 1 & 2 are off topic but I had to gripe about it anyway

3) It looks like the bond screw is not installed ,but is hard to tell in the photo
4) It's a sub according to your description so yes the neutrals and grounds must be separated,with the neutrals isolated from the panel can.

Oh yeah , Charlie B - I like the quote about reading the NEC you have a copyright on. (I was given a sticker when I took a update class given by Phil Simmons) I have it stuck on the front of one of my 2008 Nec's.

 

[charlie b]

Oh yeah , Charlie B - I like the quote about reading the NEC you have a copyright on. (I was given a sticker when I took a update class given by Phil Simmons) I have it stuck on the front of one of my 2008 Nec's.

I am honored. :smile:

 

[Rewire]

The panel is in stalled incorrectly the breakers should be verticle instead on horizontal

 

[glene77is]

Hit the "Post Reply" button below, and look for a box (it will be below the box you type replies into) labeled, "Manage Attachments."

Hit the "Post Reply"
Hit the "Advanced" <<<==== must hit this one !
then
Hit the "Manage Attachments"
and continue with
Hit "Browse" to select your photo from your PC.
Hit "Open" to have the filename pasted into the iNet page.
Hit "Upload" to have the file uploaded from your PC to the iNet page.
Hit "Submit Reply" on your posted message page.

I offer a money back warranty on this method! :smile:

 

[76nemo]

The panel is in stalled incorrectly the breakers should be verticle instead on horizontal

Want to run that by us again?

 

[Rockyd]

240.81.........

 

[hurk27]

I think he is referring to the fact that the panel is mounted 90 deg from vertical which makes half of the OCPD's turning off to be pushed up instead of down or sideways, would this be a call for a home inspector? depends upon when the panel was installed, not sure when this code was put into the book?

But separating the grounds is one and a neutral can never share a terminal, even if they were separated from the EGC's

Look at the main neutral feeding this panel, is that the ground under the neutral in the same terminal? looks like a SER cable feeding this panel

 

[gndrod]

Conductor Termination

Conductor Termination

Termination for grounded conductors on isolated neutral terminal bar must be individually connected per terminal. [408.41] rbj