ECN Forum Forums Photo Discussion Forums Photos for General Discussion Fan Cooled? Who asked for it?

First off, after seeing Bob's work on ECN before, this meticulousness in craftsmanship is par for the course. Well done

2nd, I can't imagine a fan cooled xfmr being a good idea in most cases... to start, I'm picturing this thing with all kinds of office clutter, junk, folding tables, etc. stacked around it and imagining airflow being reduced quite a bit. While of course, this is against the rules, it's going to happen anyways.. And it's going to shut itself down. Another useless service call

Nice work Bob. I'm sure it took some thought to plan all that out.

I still can't get over the parallel primary being split to land on two switches. Please let us know if your inspector questions it.

Assuming it is a listed XFMR, I would want to know how UL answers the violation (in my opinion) of 310.4

Does that mean you can use two breakers to feed it? ;-)

IIRC, the NEC has no authority over the internal design of equipment, but can require the use of listed equipment. So the Code 310.4 wouldn't apply here, right?

I sort of envision it as like a motor control center, being fed with one feeder and splitting off internally through protective devices to individual motor controls.

On second thought, even an MCC would have lugs to land parallel feeders at the same point...hmmmmm

Looking closely at 310.4, it also says: (1999 NEC)

"The paralled conductors in each phase, neutral or grounded circuit conductor shall

(1) Be the same length,
(2) Have the same conductor material,
(3) Be the same size in circular mil area,
(4) Have the same insulation type,
(5) Be terminated in the same manner."
(Bold and italics above are mine.)

So I guess GE considers this setup as complying with the same manner, notice the Code doesn't specifically say the same location/lug.

Clear as mud!!

edited to add:

And as the other have pointed out, very nice workmanship, Bob!! I wish I had your talent on my last cinema install!! (The EC was very sloppy.)

[This message has been edited by mxslick (edited 09-19-2006).]

check out firdt paragraph of 310.4.
Note words in parentheses: (electrically joined at both ends to form a single conductor)

I don't know, maybe the conductors "end" past the switches and where the connections are made at the coils.

Also, you're right that the NEC is not to be used to inspect listed and labeled equipment. It does not say that we have to blindly accept it without being able to ask how this is justified.

I've seen planty of listed and labeled equipment that somehow slipped by and was shipped to the field with a deviation from the way the equipment was originally submitted to UL.

Just a comment on the parallel conductors. I've installed as many as 15 cables per phase before.

What about the phase colors for 480v? For a time I know that we used brown, orange, & yellow, then orange was substituted for voilet. Wasn't this a code change back in 99'? Can't remeber for sure. Reguardless of the coloration, this looks like a fine definition of what quality electrical work should be.

[This message has been edited by Luketrician (edited 09-20-2006).]

Thanks for all the kind words, I have not forgotten about this thread I will post some answers.

I have one concern and I would like to hear others thoughts on it.

I am not happy with how the lugs are offset from the bus bars.

Anyone have any info?

Should I be concerned?

The lugs are connected to the bus with 4 1/2" grade 5 bolts each.

Thanks, Bob

I just wanted to say that this is an extremely nice looking installation. It is very refreshing to see the pride that all of you guys take in your work!

Bob:
IMHO, I would ask the following questions regarding the lugs:
Did they come with the transformer? Probably not.

What documentation do you have, or could you obtain from the trans mfg regarding a "spec' on the lugs?

Does mfg want 'full lug to landing' contact, with ALL six (6) mounting holes utilized??

Also, looking at the full size pics, I may have a concern with the 'C' phase (secondary) buss and the bonding conductor. Please note that I am going by what I "see" in the pic; it looks like it's touching the buss???

John

Hi John. Thanks for the email .

The bond has more clearance than it appears and more than I could provide at the grounded conductors.

When I go back I will try to get a better shot of them and the lugs.

I have darn little info from GE. Here is my thinking so far. I could have bought two separate two barrel stacker lugs for each phase. Had I done that I would have less contact area between lug and buss than I have now.

I may check the catalogs for better lugs but at this point it will most likely be left for the local inspector to decide if I actually change it.