While installing a 200A meterbase and tightening the 2"x 6" nipple, the KO came apart and (eccentric type KO's) so I made a call to the PoCo engineer and asked if I could use reducing washers as long as I bonded with a grounding-type locknut (the ones with the screw). He had no problem with having reducing washers but did not want any #4 copper in his meterbase.

What happens when the AHJ busts me for noncompliance with 250-94? Should I get an affidavit from the PoCo engineer?

geeez!

bettween the AHJ, PoCo & the customer you can really feel like the pivot man!


can you bond the other side of this nipple??

After pointing out and quoting 250-94 on his voice mail, the engineer admitted (with little argument) that I was correct on 250-94 and bonding to the Disco side of the nipple was what we agreed on. The engineer said he would even upgrade the brochures on the PoCo requirements and thanked me for bringing this up to his attention. Apparently all future services using a galvanized nipple will require a grounding-type locknut (or bushing). BTW, the brochure on PoCo requirements suggests using a galvanized nipple, but the engineer agreed that using PVC would eliminate the whole "proper bonding" problem.

[This message has been edited by sparky66wv (edited 04-05-2001).]

'66

We've been using schedule 80 pvc on Residential Services for years now. The #1 reason (for me) was because of the bonding issue. We used to use Bonding bushings and use a #6 bare solid wire taped green. Somewhere along the line they (Utility) decided they want an insulated solid #6 bonding wire - which suppliers don't even carry except by special order! That was the deciding factor for many to change to pvc.

Bill

thankfully, most utilities have an approachable EE who acts as liason for utiltiy-nec conflicts,no-no's get addressed, errors get corrected

Virgil;
many of those KO's are inconsistent, some take a beating, some fall right out, probably no challenge for those bass-calloused fingers eh??

'66,

You actually got an Allegheny Power Company employee to commit to something? Mark it on your calender, you're not likely to see it again in your lifetime.

As other posts suggest, bonding can be at either end & the panel side is usually easiest.

Be glad you aren't in Clarksburg. The AHJ was (at one time) insisting on a 3rd ground rod because the nipple between the meter socket in panel was PVC & there was no bonding bushing. Swear to God!

Tom

What about keeping conduit electrically continuous from end to end? Shouldn't there be a grounding bushing on BOTH ends as per 300-10?


[This message has been edited by sparky66wv (edited 04-09-2001).]

66'
tell me your thoughts on 250-92(a)3

'66,

The bonding bushing only needs to be at one end. The two locknuts (for a GRC nipple) on the other end make it electrically & mechanically continuous.

Best way to avoid needing the bushing (sometimes a grounding locknut will work) is to use PVC when possible, except in Clarksburg with that dad blasted third ground rod.

Sparky,

As far as 250-92(a)3 is concerned, if the job specs don't specifically call for additional protection of the GEC, use one big enough to withstand a little abuse so you don't need the conduit. When I lived out west, we used to be able to buy a ground rod clamp that would connect a 1/2" GRC to the rod & provide a connection for the GEC. It was made of malleable iron &I believe they were called "Terry Clamps" (brand name). Haven't seen them since I moved back East. You ever seen them?

Tom

[This message has been edited by Tom (edited 04-09-2001).]

Tom;
i think i know what you mean,i only see them on older services once in a while. probably before pvc was popular

There are KO's on the disco and the meterbase sides of the GRC Nipple. Do the locknuts on one end still comply?



[This message has been edited by sparky66wv (edited 04-09-2001).]

66'
i'm confused here!
is this a continuos piece of #4, or are you just using small pieces to bond ???

The grounding locknut doesn't fly out here due to the fact that there is not a solid path from the washers to the can = bushing. The ground clamps mentioned above(1/2" conduit to rod or pipe) are available from Weaver/Blackburn as a #JP-12, JP-34, etc. They've got a conduit hub, and a PASS THROUGH lug (not just a wraparound screw w/ washer) for the larger sized GEC's. 1/2 of the clamp can be reversed for rods, and they'll fit a 1/2 through 1 water pipe. Made of bronze.

[This message has been edited by electure (edited 04-10-2001).]

Sparky...

Here goes...

The GEC is one continuous piece between the neutral/ground buss in the disco and the two ground rods.

However, the "bonding wire" for the nipple is a short piece to the neutral/ground buss, it isn't there to ground anything (defining 0 volts), the bond screw does that, but it is there to assure ampacity on the nipple through the KO's in case of a ground fault. Should I put this in one continuous piece from the Ground rods to the nipples to the PVC water pipes (a little joke there) to the grounding bushing and out to eveyone's house in the neiborhood? OK so I'm going extreme here but bring on the flames...

BTW, if this is true than there are zero houses in Greenbrier County that meet code.

66'
well 250 is the flame-daddy of all articles.
one bone of contention is in the fact that the entire article has been reshuffeled, so there is a continuos line , so one cannot use the glorified line to decipher 96' to 99' changes.

i think i understand your configuration now, thanks!

let me ask a Q

does 250-142 allow the noodle in the meterbase, which i take is integral to the enclosure to do the job of 250-94???

isn't that noodle a "dual-usage" conductor up til the main disco??



burn baby burn!



[This message has been edited by sparky (edited 04-10-2001).]

Sorry Man... I was in a foul mood this morning (on my tenth workday in a row plus two gigs this past weekend...and to think I was complaining of not enough work two weeks ago...)...

As you stated in your Q, the meter base is bonded to the neutral, as per 250-142, and the GRC Nipple is bonded on the disco side, so I suppose that it is electrically continuous with only one grounding bushing, although the fault current would have to "backfeed" to the neutral buss, to the neutral conductor and finally back to the meterbase... depending on what size OCPD the pole-climbers have protecting the Xformer, all this rube-goldberg connecting could have a significant resistance; just seems better to have the nipple bonded to the meterbase side straight to the unused lug on the neutral bar... Just a theory...


[This message has been edited by sparky66wv (edited 04-15-2001).]

66', it's cool....
the bonding a both ends was an angle about GEC's as applied to your scenario 250-64(e),if you had been allowed to pass it in one piece thru to the meterbase, our local utility allows this!

250-142 allows you to connect the GEC anywhere up to the service head! It does not directly come out and say this, God forbid any clarity that simple should exist in the NEC! It implies this by way of allowing a dual-usage conductor, which in itself could be run thru the GRC and used to bond it on the way to the panel. At least the way i read this.

Current will follow a parrallel path thru the bonding jumper in the MDP,thru the panel enclosure, thru your GRC, to the trans as well as thru the noodle.

So how does the intent of 250-6 NOT get violated in every service installation?

Of the GEC, EGC , and bonds, i'm not as sure about what item does what job anymore, i don't mean code wise, i mean the hardcore theory.

Case in point;
The Utility here, as many do, tie all the X-formers noodles to a pole ground AND the high side noodle, one big happy ground throughout the line extension covering miles...
I'm not clear as this is an asset or liability in terms of outside influences.
Except when they get to a dairy farm, then there is no pole ground, and a isolated noodle at the trans!!!nothing on it but one line to the farm!
The theory being that only ONE point reference (noodle to earth)is, and works best.....hell we gotta keep them cows happy!
So why can't the same hold true for any other installation????It seems the NEC is bent on having us install parallel noodles!

other threads with individuals well versed in this area have me questioning all the heavy 2-sylable programming out trade seems to be let loose with

OH!, i remember those 3 night-in-a-row gigs!I don't miss em', but i'd still like a crack at that 6-string of yours, what make is it??


[This message has been edited by sparky (edited 04-10-2001).]

[This message has been edited by sparky (edited 04-10-2001).]

It's a Carvin, model number unknown cause Carvin hand makes them to special order. It cost me $1200.

The EE wanted NO #4 bare in his meterbase, period, whether it was a GEC or an EGC. Only the six 4/0's allowed (3 wire line and load).

Perhaps parallel neutrals would help to cut down on lawsuits resulting from "240V series circuit" "meltdowns" from lost neutral connections?

Just a thought...

[This message has been edited by sparky66wv (edited 05-04-2001).]

Would it be OK in this case to use a lay in lug type bonding bushing and run the neutral through it on the way to it's terminal in the meter base.
--
Tom

I ended up using a bonding bushing with a #4 bare bonding jumper from the neutral/ground buss... my intentions were to insure ampacity in case of a fault.

I now use PVC insead of GRC Nipples to remove the extra costs and concerns with this particular setup. (From advice given by the guys here! Mainly Bill...)

To this day the inspector readily passes services with GRC Nipples, Concentric KO's, and no bonding bushing or locknut. I even left a message on his answering machine concerning a question with 250-94, but no answer.