Subpanel Bonding Screw

Specific Inspection Topics Electrical Inspections
1

Ok let’s get the horse out again. Today, I came across the situation shown in the photos below.

The green screw I know is used in main disconnect panels to get the neutral bar bonded to the cabinet. However, this was used as a subpanel. I don’t think the screw is supposed to be there but it looks like it isn’t fully in place so it may not actually be doing anything. Am I off the mark on that?

In the first picture you can see they did install a third grounding bar directly to the cabinet. The screw, if not fully in place, would then let the neutral float but I don’t know that for sure and I was NOT going to stick a screw driver in there to see if it was tight or not.

So I am recommending that a Lic. and Qual. Electrician remove it or say it is ok. This is new construction and I am guessing that someone just forgot to pull the screw out completely.

FYI, The first picture is the lower portion of the panel. The second is a close up of the screw in question.

I will be working on the report tonight so if someone sees this and I need a good smack on the back of the head please reply. Subpanels are one thing I rarely see so I generally have to check my books and compare that to my pictures to make sure all it ok.

Thanks.

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2

Hi Andrew,

I agree with your take on the panel, the bonding screw looks like it has been backed out far enough so that it has no potential to the enclosure, but I would also prefer to see it not there at all (just incase someone decides to tighten it up). also this is not wrong but looks odd, why did they not just remove the neutral bus bond and use that as the grounding bus with a bond to the enclosure, that is more normal practice.

Was this installed by an electrician or a “gifted amature”?

Regards

Gerry

3

Andrew:

The green screw is the “main bonding jumper” to be used and installed in the main service disconnecting means. It should not be left in that panel because someone else taught in another world would probably screw it in :roll: and the attached image of your picture shows me that there is not a proper fitting and looks like whoever did that work was not familiar with the construction and operation of electrical equipment.

I may be wrong, but the panel looks like it is upside down??

Sure wish I could see more, so that I can help you cite more problems if any? I will be in Texas soon, and it is my understanding that they have been licensing electricians there for a while now, that’s good but if this is the type of work they do there I would be weary??

4

Good eyes there Joe

5

Didn’t catch that at first. It does appear to be upside down. Look at the “keyhole” in the center of the panel at the bottom. And the white paper tag, writing is on the wrong side.

6

I do not recall a code to require it to not be upside down.

7

Ben:

Some cabinets have the word “TOP” engraved into the metal. Not a major problem, but if the main was installed it would be incorrect.

Can I go and see a panel in your area when I come to Memphis?

8

You can help yourself, but I am 2 1/2hrs from Memphis. I beleive there is a moore, or moewe that post who is from Memphis. I would help if I was closer. What do you have going on in Memphis

9

Joe, If the panel is turned, many breakers can also be turned in the panel to compensate for this. Is that not correct? I can remember doing it several times.

10

Is the ground behind the bar or in it?

And how is the romex on the lower right pull through?

11

We install panels upside down all the time…most general service enclosures today can be installed either way. The panel shown here is fine to be installed upside down…perfectly safe and fine.

Among the other issues already stated…I would also note the neutral if it is # 6 AWG or smaller…would need to be continuous white or gray outer finish or by three continuous white stripes on the other than green insulation anong its entire length.

12

The romex looks like it is in a plastic conncector (as far as I can tell). The ground is in the lug.

13

This is why the electrician should put these things in their pocket when they are not dictated to be installed. I bet someone just stuck it in there later because they found it and didn’t know what else to do with it. Take it out and throw it away.
Since all the breakers in the panel seem to go sideways I don’t think there is a top or bottom. This is only important when you have up/down action on a breaker. Up “shall” be on. It is an ugly entrance on that raceway for the feeder.

14

What do you have going on in Memphis?

Memphis, TN: February 21-22, 2006

Mobile, AL: February 23-24, 2006

15

I agree with Gerry’s initial comments. Seems more logicaal to have removed the bonding jumper between the factory installed bus bars, bonded the left bar to the panel with the intended green bonding screw, run the grounds to the left bar, and the neutrals to the right bus bar.

I guess there is more than one way to skin a cat, as they say.

I have checked for continuity between the neutral bus and the panel in the past, though it is WAY beyond the SOP. I also agree that if the intent is to NOT use the bonding screw, it should have been removed at the time the panel was installed.

16

Thanks to all for the help.

I will leave the recommendation to remove the screw just so nobody torques it in for good measure.

Gerry,
Yes, this was an electrician, it is a new construction so I can only assume nobody got in there and goofed around. As to why they didn’t pull the jumper, you got me. Often, in the bigger homes and especially in new construction, they will just have two main panels rather than a main and a sub. Maybe it was a newbie electrician and he didn’t think to remove the bar? Or maybe the electrician did it that way initially but the AHJ freaked out when he didn’t see the two bonded and the missing screw and made them put it in there.

Joe,
Yes both panels were installed “upside down”. There are a few other issues that I found with the main panel that makes you wonder just how hard it is to get licensed as an electrician in Texas. But this one is not as bad as others I have seen. I think the bigger problem is the AHJ not doing there jobs as carefully as they should.

I attached a couple other photos for your enjoyment. The first two are the upper portion of the subpanel. The next three are the main panel top to bottom. I have until tomorrow morning to get this report out and can check back before I finalize it, in case you or anyone else finds something.

Larry,
There is a bushing on that one, I checked, but thanks for the reminder. In the main panel there is some unbushed Romex that I didn’t get in the first go round of report writing.

Paul,
They only had the two ends wrapped with the white tape. The entire length consists of about 24" or so, maybe they just said fuggetaboutit and didn’t bother.

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17

http://www.mikeholt.com/onlinetraining/page_images/1011648934_2.gif

This section was revised to read:

Enclosures for overcurrent devices must be mounted in a vertical position unless it is impracticable. Circuit breaker enclosures can be installed horizontally if the circuit breaker is installed in accordance with the requirements of 240.81. Figure 240–3Intent: The change restores the “impracticable” rule, which had been in the NEC for over 70 years and was inadvertently removed during the 1999 rewrite of Article 240.

Author’s Comment: Section 240.81 specifies that where circuit breaker handles are operated vertically rather than rotationally or horizontally, the “up” position of the handle must be in the “on” position. So in effect, an enclosure that contains one circuit breaker can be mounted horizontally; however an enclosure containing a panelboard with circuit breakers would not be permitted to be horizontal.IE: This was to furthur explain what Greg was talking about in regards to panel breakers…Courtesy of Mike Holt Ent.

18

http://www.mikeholt.com/onlinetraining/page_images/1008699514_2.gif

The term “natural” was deleted and a FPN was added to this section. It reads:

(A) Identifying Grounded (neutral) Conductors 6 AWG or Smaller. Grounded (neutral) conductors 6 AWG and smaller must be identified by a continuous white or natural gray outer finish or by three continuous white stripes on other than green insulation along its entire length. Figure 200–3

Author’s Comment: The use of white reidentification tape, paint, or other methods of markings is not permitted on conductors 6 AWG or smaller.

NOTICE: Text that is strikethrough is intended to represent text that is no longer contained in the 2002 NEC.

(B) Identifying Grounded (neutral) Conductors Larger than 6 AWG. Grounded (neutral) conductors larger than 6 AWG must be identified by a continuous white or natural gray outer finish along its entire length, or it can be identified by distinctive white markings such as tape, paint, or by other effective means at its terminations. Figure 200–4

Author’s Comment: Reidentification can be with white tape but not with gray tape.

(D) Mixing Grounded (neutral) Conductors from Different Systems in the Same Raceway or Enclosure. Where conductors from different systems are installed in the same raceway, cable, or enclosure, one system grounded (neutral) conductor must have an outer covering of white or natural gray. The other system grounded (neutral) conductor must have an outer covering of white with a readily distinguishable different color stripe (not green) running along its entire length. Figure 200–5

FPN: Care should be taken when working on existing systems because the color gray may have been used as an ungrounded (hot) conductor.

Intent: This action will address the concern expressed by many that the term “natural gray” is not defined and there is no recognized color or tint that one can readily associate with that term. The addition of the Fine Print Note is to warn individuals that there may be electrical systems where a gray conductor was used as an ungrounded (hot) conductor.

Author’s Comment: The panel rejected a proposal that would have specifically limited white to be used with systems below 150V to ground and gray to be used above 150V to ground. In addition, the panel rejected a proposal to allow 6 AWG and 8 AWG grounded (neutral) conductors to be re-identified in the field by the use of white or gray marking. It could be difficult to distinguish the difference in color between a white and a gray conductor in the same raceway after it has gotten dirty or if it has aged.Images courtesy of Mike Holt Enterprises

19

Electricians around here don’t care which way the panel is installed as long as the breakers don’t read “NO” instead of “ON”.

20

Ok guys,

I’m trying to learn, so forgive me if I ask some really dumb questions…

In this picture

http://www.nachi.org/forum/attachment.php?attachmentid=1443&d=1140410796

The rats nest of wiring at the top. Is that all NM cable stuffed in one conduit? How are they secured as they enter into the service panel? Wouldn’t there be a derating factor for all of those bundles of wire if the were in the same conduit? I can’t tell if its conduit, or how the wires are secured. Is it really OK to bundle wires with a piece of wire? If you are going to do it, why not just zip tie it with a tie wrap?

This one…

http://www.nachi.org/forum/attachment.php?attachmentid=1444&d=1140410817

What about the two neutrals sharing the same screw on the grounded bar? And on the other side, the neutral and grouding conductor sharing the same screw? Is it really OK to have white wires for a hot leg on a 220 circuit? I thought it was supposed to be red…or any other color except white (or green.) I’ve seen this before, but it just looks really odd to me.

And the last one…

http://www.nachi.org/forum/attachment.php?attachmentid=1445&d=1140410835

I can’t see the conduit that feeds the subpanel to the right…Where is the insulated bushing for the box, or the locking ring for that matter? Is this the “other end” of the conduit that Joe was commenting on earlier?

Like I said…still learning so go easy on me.

Dave