How to inspect? It's new to me!

Status
Not open for further replies.
davedottcom

davedottcom

Senior Member
I was hired to inspect some solar pv jobs, not for the AHJ but just as an experienced electrician & solar pv installer to give the owners my opinion of the installation.

My first question would be, how does an inspector verify whether a lug is or is not listed for more than (1) conductor?

McKinleySchool004.jpg


Second, how does an inspector verify whether a lug is listed for wet locations or not?

McKinleySchool018.jpg


3rd question, how many violations can YOU see here?!? The conduit that enters the top is the 410 Vdc PV source circuit & the conduit that exits out the back goes to the inverter.
CanonCityHighSchoolPV007.jpg
 
If you take a look at the Thomas and Betts site for lugs http://www.tnb.com/ps/endeca/index.cgi?a=nav&N=3768+2622&Ntt= for example. You'll see that any lug with one hole ,for conductor connections, is described as being for a "single conductor" and lugs with more then one conductor connection are listed for "two-three-four-etc conductor" connections respectively. So the single lugs shown in the pictures would probably only be rated for one conductor unless specified on the panel as being acceptable for more then one. IMHO
 
The lugs in picture 1 look oblong, probably good for 2 conductors. It will say this on the front, might be partially obscured by the nut.

Lug in the second picture have a washer behind it???
 
The inspectors in my area would check that the outside grounding lug had anti-oxidant used with the copper wire. I don't know exactly what brand of lug that is, so I don't know whether the manufacturer requires it.
 
I can't see for sure, but I believe that is a grounding clip behind the lug in the second picture. If so, that's good that it was used.
 
Last edited:
I was taken back by the 3rd picture. What's the deal with the "S" conduitors between disconnects? If they isolated them properly wouldn't that work, in respects to the lug size?

One each side, top to bottom, after I straighten that out, I released they had the wrong circuits in the wrong places...

Did they burn up anything? Your going to tell me they were just incorrectly labeled... :grin:
 
As far as the lugs are concerned, you would have to check the manufacturer data to be sure. Most are marked, although not easy to read especially with the conductors installed.
As Chris noted, if they are good for two conductors most will have an oblong or "figure 8" hole. One round hole is usually one conductor.

On your connection to the steel make note of NEC 250.12

As far as pic #3, someone more familiar with PV system such as Bob could probably make a long list, but it appears we are switching the grounded rather than the ungrounded conductor and we have a grounded/grounding mix on our terminals and possibly undersized grounding, as well as parallel conductor violations.
 
cadpoint said:
I was taken back by the 3rd picture. What's the deal with the "S" conduitors between disconnects? If they isolated them properly wouldn't that work, in respects to the lug size?

One each side, top to bottom, after I straighten that out, I released they had the wrong circuits in the wrong places...

Did they burn up anything? :grin:
Click to expand...

This blew my mind! I have no idea why they would even think of doing this... I see no point in it although I don't believe having the feeder run through the disconnect twice is a violation... but why...why...why? :roll:

The violations I was noticing were.
1) the positive is identified with white
2) the Neg is black
3) The line & load are reversed
4) 2 conductors under what appears to be a single conductor lug
 
augie47 said:
As far as the lugs are concerned, you would have to check the manufacturer data to be sure. Most are marked, although not easy to read especially with the conductors installed.
As Chris noted, if they are good for two conductors most will have an oblong or "figure 8" hole. One round hole is usually one conductor.

On your connection to the steel make note of NEC 250.12

As far as pic #3, someone more familiar with PV system such as Bob could probably make a long list, but it appears we are switching the grounded rather than the ungrounded conductor and we have a grounded/grounding mix on our terminals and possibly undersized grounding, as well as parallel conductor violations.
Click to expand...

The actual polarity is correct, but they are identified incorrectly.

As for the Disconnect lugs, they do have a sort of figure 8 shape to the conductor opening, But the small oblong opening is where the set screw is, I can't imagine a conductor ever utilizing that space.

Yes, I believe there is a kind of washer installed behind the grounding lug that "bites" both surfaces... this is a good thing! :)
 
cadpoint said:
I was taken back by the 3rd picture. What's the deal with the "S" conduitors between disconnects? If they isolated them properly wouldn't that work, in respects to the lug size?
Click to expand...

Well, no... since they are paralled they need to be on the same phase so splitting them to (2) different phases in the disconnect would be incorrect (I believe!?) but they could have simply used either the LINE & LOAD lugs on the A phase or the B phase. Nothing wrong with leaving the other set of lugs unused.
 
Status
Not open for further replies.
Top