Service panel ground

mathew stouffer · 01-19-2010, 06:19 PM

This is a service with 2 100amp disconnects. One of the GEC' is connected to a ground rod and the other is likely for a ufer, although I could not locate it. Does the ground bar need to be bonded to the panel?

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**Jerry Peck** · 01-19-2010, 07:06 PM

Based on what I see in the photo, it probably already is, but I cannot tell for sure from the photo.

Did you look at the schematic? That would have answered your question.

Roger Frazee · 01-19-2010, 07:43 PM

Originally Posted by Jerry Peck

Based on what I see in the photo, it probably already is, but I cannot tell for sure from the photo.

Did you look at the schematic? That would have answered your question.

I agree Jerry

This is a Square d Homeline "All in One" meter combo that does not use a main breaker but subfeeds other panels or air conditioning ... etc. It will be configured to the 6 disconnect rule in most cases.

The neutral bonding strap comes in at the lower left and you can see grounding lugs that egc's for the two 4 wire sub-feeds are attached.

I have never seen a meter can like this ever listed for any thing but service equipment. It should say on the spec sheet "Service Equipment Only".

mathew stouffer · 01-19-2010, 08:04 PM

most of it was too faded to read

**Jerry Peck** · 01-19-2010, 08:08 PM

Originally Posted by Roger Frazee

The neutral bonding strap comes in at the lower left and you can see grounding lugs that egc's for the two 4 wire sub-feeds are attached.

Which I am suspecting goes up, behind the upper panel, and across and down to the two terminal bars on each side of the hot bus bars.

It should say on the spec sheet "Service Equipment Only".

Yes, if it says "Suitable for use as Service Equipment Only", then the neural and ground terminal bars are permanently bonded to the enclosure. But what confuses me is that is those cases the neutral and ground terminal bars are mounted on the enclosure, not on a plastic isolator base as shown in the photo.

That is what is confusing me and causing me to wonder.

mathew stouffer · 01-19-2010, 08:17 PM

That is what I was thinking. I could not see any bonding screw on the right side where the 2 GEC's connect to the bar.

Roger Frazee · 01-19-2010, 09:50 PM

Originally Posted by Jerry Peck

Which I am suspecting goes up, behind the upper panel, and across and down to the two terminal bars on each side of the hot bus bars.

Yes, if it says "Suitable for use as Service Equipment Only", then the neural and ground terminal bars are permanently bonded to the enclosure. But what confuses me is that is those cases the neutral and ground terminal bars are mounted on the enclosure, not on a plastic isolator base as shown in the photo.

That is what is confusing me and causing me to wonder.

Yeah that's understandable. Boy... I've looked in all my catalogs and over at square d and I cannot find this combination meter main configuration.

If we only had the model # ...

Every piece of metering equipment square d shows is service equipment only.

Best drawing I could find that was close was this one below and it was service equipment only. If you could take the access panel off above the main lugs you would see a metal strap with drop downs to each neutral bar. But without verification on the panel spec sheet you should not take my word for it. If you look just below the top access panel edge in between the main bus bars you will see a large N. This is a protective plastic cover that they use to keep the neutral protected from the main bus bars as it passes behind them. The bends you see in the main buses is to allow clearance to pass the neutral behind them.

mathew stouffer · 01-20-2010, 08:32 AM

Thanks Roger. I have to go back and pick up a radon test, I will check it out. If you are wrong I am sending Jerry to beat on you

Roger Frazee · 01-20-2010, 08:50 AM

Originally Posted by mathew stouffer

Thanks Roger. I have to go back and pick up a radon test, I will check it out. If you are wrong I am sending Jerry to beat on you

Well that does concern me because I've already lost a couple bets to him. I don't think I would want to face him in a poker game......

EDIT: As a word of caution you generally do not remove that top access cover unless the meter is pulled.

You might be able to look right behind the lugs at the top of the neutral bars and see the attachment means to the bonding strap.

**Jerry Peck** · 01-20-2010, 05:17 PM

Originally Posted by Roger Frazee

Every piece of metering equipment square d shows is service equipment only.

Which is only logical and makes sense.

If you could take the access panel off above the main lugs you would see a metal strap with drop downs to each neutral bar.

Which is what I would expect, but ... the ground and neutral terminal bars are also isolated from ground on that plastic backing ... which does not make sense and is not logical.

Roger Frazee · 01-20-2010, 09:44 PM

Originally Posted by Jerry Peck

Which is only logical and makes sense.

Which is what I would expect, but ... the ground and neutral terminal bars are also isolated from ground on that plastic backing ... which does not make sense and is not logical.

Probably just a matter of cost cutting and use of common parts in manufacturing. These are the same interiors they use in their residential load centers. Below is a picture of a sc2040M200S this is a meter 'all in one' all of the sc series have the insulated neutral bars but they are service equipment only. This one has a main breaker but is the generic image for all the sc series meter mains. If you search squared d CSED's you will see several like this. And you will see ones like you mentioned without insulated neutral (s).

I am not sure, since this is the same interior as a HOM20/40M200C, if they use a removable green main bonding jumper (screw). However on the meter side the bonding strap/bar is bolted to the metal enclosure where there is a lug for the bonding bushing if required and the line neutral. It would be nice to see the spec sheet on the meter enclosure being discussed.

I cannot think of a reason for this equipment to have the need for separation of neutral and ground. You can add grounding bars to some of these type enclosures that have main breakers or main lugs but generally only the ones that have several breaker positions (circuits) provide for this accessory.
.

I do not think that the listing language would be affected whether or not the main bonding jumper is removable. But like I said Square d shows these panels as 'service equipment only' .... soooo

http://static.schneider-electric.us/docs/Electrical%20Distribution/Combination%20Service%20Entrance%20Devices/CSED,%20Meter%20Mains/SC/3189.pdf