OK... Got caught up in a job for a Veterinary Office/Kennel. I've been a good sparky and have went with PVC FS boxes and WP covers to protect from washdowns.

Time comes for the service, and it really could get away with 100A (gas heated building) but I figured for 200 for upgradability...

Using the only available conductors from my supplier for a 200A service, I ran 2" PVC from the disco to the panel, and installed the 4/0 Tri rated "new stuff" that's really easy to work with.

Several things suddenly came to a really bad light...

The neutral is 2/0...

Table 310.15(b)(6) is for dwellings only!

My 2" pipe is too small for 3 250KCm conductors and a #2 Ground...

GE brand 150 Ampere Mains are rare as hens teeth.

I asked my AHJ what to do and he said:

"You mean to tell me that 4/0 is big enough for 200A in a home, but not in a business?"

I was dumbfounded...

He suggested that I was "reading too deep into the code."

Hunh?

You can't use 3/0 or 4/0 cu? I would think either of those would be available at your supply house. Were you originally running 4/0 Al URD and a #2 through the PVC? Our supply house has been stocking 4/0 Al URD quad(4/0,4/0,4/0 & #2)which can come in handy for residential when using a disco.
I don't know how far your run is but if I lived near by I'd make you a deal on some 4/0 cu. I've got about 21 pcs. 65' long left over from a 330' pull I did last year that I'm still trying to forget.

Tri Rated Cable, (RHW-2, XLP, USE-2) with 2 4/0's, a 2/0 Neutral (with requisite white stripe) and a #4 Ground (green) all Aluminum and twisted into a single cable. There are three LB's and a Sweep in this pull, and I'm a solo act, so pulling THHN Cu conductors would be a BIG challenge. (It was hard enough pulling the tri-rated cable...)

I guess the sad point to this is I don't have to change it... The AHJ will pass it as is, and doesn't understand why it shouldn't...

I guess an AHJ around here has to be real lenient...

Virgil,

FYI, The PoCo around here only uses 1/0 Alum underground to Meterpan for a 200A service.

Bill

per C-10, 4-THHN 3/0's CU's will fit in 2" sch 40,(so less with reduced noodle & ground) 310-16 @ 75 deg, meets 110-14(c)(10(b) , which i'd only do if called on this, with a gallon of 77 to boot....

I'm confused...

So... 310.15(b)(6) can be used for commercial if the PoCo has undersized their conductors? Where does it say that?

I'm so lost...

Cu Thhn is out of the question... Did I mention 3 LB's?
Maybe my technique is bad, but I can't pull 3/0 Cu Thhn through the bend of an LB in sub-freezing weather without some major help... Three strong men and a hammer... (poor conductors)

I guess I'm just lazy...



It's all moot, they'll pass it anyway, and I'll be thought a fool by everyone I work with if I change it...

That "inspector's" response is simply amazing. How big are the LB's? Mogul sized I hope. Are the covers for the LB's spaced out 4" (required distance per 314.28(a)(2)exc.)

Elzappr;
Have you priced out moguls lately? or asked for a lead time?

Moguls? Dunno... I doubt it...

4"? What, from the hole in back to the cover?

I doubt there's 4"...

Boy, I've opened a can of worms...

Heh... I'd like to see some of you guys do business here... You'd get one job (if it's T&M, you'd never get a bid job unless you're willing to bid a price lower than just the materials cost...) and then it would be over... "He's too expensive and too hung up on code" would be your reputation... don't mean to sound bitter, but I've had a long rough year,

What I've learned?

Complete "to the letter" code compliance = starvation

A pretty simple equation really...

Exactly! Thats why we have to find a way to clean up our own act. I don't know the answer tho. I got virtually no reaction to my earlier question about legal liabilities for under-compliant installations. I was hoping that SOMEONE would be familiar with the topic and reinforce the notion, that I think is brooding throughout the country, for holding electricians accountable for their "make-do" pragmatic methods. I'm just trying to look ahead, so that what I do today doesn't come around and bite me 15 years from now!
Inspectors look at the closed boxes and make sure there are no openings for the fire to blow out of, but its up to us to not make those loose connections, or to not hammer those conductors into the LB's.

[This message has been edited by Elzappr (edited 01-06-2002).]

Virgil,
it's just as bad here....
to be torn bettween trade ethics and being competitive is not a position i enjoy.

I'm starting to think this could only occur as a grassroot endevor....

Sparky, yes, no denying that moguls are pricy! Perhaps LB's should have been substituted by pull boxes instead..although there were probably job factors that precluded that choice. As for lead time, I'd bet that there would be a lot of older electricians that would like to rave about the newer "minimal inventory" management methods of wholesale houses which began about 15 years ago.
Sparky66wv, don't know how the distance is measured..just being the Devil's advocate here. I haven't seen an inspector yet who gave more than a quick glance at the sizes of condulets and shape of the covers.. I'm using this site to probe a little..to see how things are done outside of Oregon.

Elzappr - Sparky,

Your comments of being bite 15 years down the road - .

I would like to see some court rulings on disasters that were caused by poor wiring installations. What few I see in newspapers or magazines seem to be settled out-of-court so that no outsider knows what was the outcome.

In my estimation, many wiring shortcomings would not showup for several years, such as
derating of 310-15(b).

Just a three weeks ago, I saw where 30 volt landscaping 2/C was installed in a 120V chandelier fixture made by a prominate fixture manufacture which makes listed and unlisted fixtures. Did not see a listing make on this un-assembled chandelier.
That 30V 2/C wire would probably lasted several years before a break-down and then the owner would probably want it replaced/repaired so quickley, that no-one whould check why the fixture went bad, JUST GET IT REPLACED !!!!

Virgil,
Sorry, I shouldn't have mentioned that here. I was trying to offer something that might explain why the Inspector might have the viewpoint that he does. I was also picturing a very short run.

Can you still order a 150A main ?

Bill

Virgil,

Don't lose any sleep. See 240-3(b). I myself would have opted for 3/0 copper or 250 alum, but done is done & I don't see much of a problem here. There was a time, not that long ago, when Allegheny Power did require 250 mcm Aluminum on non-residential 200 amp services.

Also, I know you're smart enough to use an LB that is marked with the maximum size of conductor allowed so that you don't have to worry about 314.28(A)(2) exception because you're in compliance with 314.28(A)(3)

Here in the Mountain State, we should probably hold off using the 2002 NEC for at least another 5 or 6 years.

Tom

[This message has been edited by Tom (edited 01-07-2002).]

Sounds like a good semi-escape route, Tom, but for the issue of conduit fill. I'm not sure, but I think C10 lets you know that 2" PVC is maxed out by the 4/0. So 314.28(a)(3) doesn't apply (or, using '99 Code, 370-28(a)(3)). The reason why I'm saying I'm 'not sure' is that the tri-rated "new stuff" cable Virgil used isn't listed in C10..but for 'RHW-2',and THAT insulation would only allow TWO 4/0 conductors in 2"PVC. If the conduit wasn't maxed out, then it would be cool..per your comments..except for the confused inspector call that permitted 4/0 in the first place.

If Virgil's cable is without the outer covering, he is OK all the way. See the little asterisk at the bottom of C10. I'm not sure either.

Also, those tables assume all conductors are the same size. Virgil is using a 2/0 neutral. If you look up the dimensions of RHW-2 in table 5 & add everything up, the area comes to 1.2913 inches & the maximum permitted is 1.316 (table 4) Things get even better if you look up the RHW-2 with the asterisk.


One thing that I do know is that XLPE isn't a listing. It stands for cross linked polyethylene & this is the main ingredient of some of the thermoset insulations.
Tom

It looks even better with compact conductors..but we don't have that info to go on.

No outer sheath, and I think it is compact wire...

Something about "compact building wire" written on the insulation...

It's very soft and flexible in comparison to THHN or the old USE...

It's catalogued as "Mobile Home Cable" at the local supplier...

"WMOBLE4/04" is the catalogue #...

Am I clear as mud yet?

Yeah, sounds like workable stuff. So how did it go?

The trench has failed the PoCo's inspection, so the fellow who dug the trench is holding things up now...

The trench crew was a plumber, and he only dug the trench at 18"... I told him I needed 24" of cover, which would be about 28" deep with 3" PVC... But alas, no one listens until after the fact...

The ground will have to thaw first...

Don't have the ground rods driven yet either...

I'll be there tomorrow, we'll see..

(The saga continues...)