Circuit routing

[weressl]

"Creo que no, Timoteo":roll:

There is little in the code requiring 'technically sound". In fact one might think 90.1.B (2008) suggests one may be about as moron as one wishes - just so long as the installation is essentally free from hazards



Assuming this comment applies to using adequately protected single conductor type W: How is this "TECHNICAL(L)Y wrong and and potentially DANGEROUS"?

JFTR I would go with your recomendation, 3C - w/G, type G, 4/0. It is fairly common and not too bad to handle - as long as it was direct connected and the installation did not require a cord and plug connection.

ice

Three/Four conductor cables assure that the cable lengths for each phase conductor are close to equal, and routed along the same physical path: the rule for parallel cables. If you understand the function of the two requirements there, the same applies here.

 

[weressl]

Yes that is true.

Most of the installations I deal with (and I deal with a lot*) of this type, have a J-box with a PDB rated for fine-strand conductors, right next to the controller. And that makes the 90C column effective.

Since few of the controllers are rated for fine-strand about the only other option is to use 250, as you correctly noted - and then crimp on an adapter - such as a Shoo-pin.

Additionally, 250 Type G is not usually readily available - 4/0 is. Unless one is feeding a PDC, and a neutral and equipment ground is required - then one must go to type W, 5C, and 4/0 is about as big as is available. AND, the electricians tell me they really prefer 4/0 over 250

The Worm (is suposed to be working - but is goofing off )

* "a lot" is defined as several temporary power installations of this ilk per year.

Could you link me to the make and model of that PDB that is rated both for fine strand conductors and 90Centigrade rise? My concern is the repeated connect and disconnect, and we may or may not get the same machine(s) eevry time, but have you seen what happens to a fine strand large conductor after repeated connections? Gets chewed up so eventually you have to make a fresh cut. Seems to me that a compression lug connection is the way to go.

 

[iwire]

but have you seen what happens to a fine strand large conductor after repeated connections? Gets chewed up so eventually you have to make a fresh cut.

We do make fresh cuts most every time, but yes compression lugs would be much better.

 

[iceworm]

I suspect that I don't have too much to add that you don't already know.

First, I have not ever had to put is a temp power of this size where the plan was to yard it in and out every 6 weeks - possibly for ever.

From that prospective, Iwire's recomendation is a good one. For your application lugs sound like a better deal. As you likely already know, Burndy YA and Ilsco FE are rated for fine strand.

Square D has a application note on using fine strand with mechanical lugs. http://ecatalog.squared.com/pubs/Circuit Protection/0515DB0301.pdf
Interestingly I had an suthority tell me that this applied only to square d lugs - I could not use this method on a seemingly identical burndy or tnb. My response was, "Yes sir."

As for PDBs and fine stranded, I like Marathon
http://www.marathonsp.com/PowerBlocks.html
Some show an amperage based on the max wire size and 75C column. However mechanical base rating is 125C to 150C. Some don?t show any temp rating other than the mechanical base rating.

Other blocks are rated for 90C but not fine strand. Of course, one then uses a ferrule such as a Burndy YF, or a http://www.greaves-usa.com/pdf/Shoo-Pin Color Sheet.pdf

http://www.ilsco.com/StaticContent.aspx?id=zp8YhmZrpjUhg1J3WSZflg==
These are rated fine strand and 90C. I haven?t used these. But some of the other crews have used a similar (but smaller) Polaris - and they like them. As I recall, the polaris only goes up to 3/0. This ilsco goes up to 350. I'll try the ilsco next time if available.

You may also wish to look at UL 1953 and UL 1059. These highlight the differences between listed connectors and connectors that are recognized components.

I have to quit - To quote Jim D, I have already told you more than I know.

ice

 

[Rockyd]

A look at 392.11 in it's entireity might be an idea...

 

[weressl]

I've got a couple of questions that really don't apply, but I am curious:

Is this compressor and cables a rental unit or are you purchasing?

Rental.

You say it is a "manufacturer" and every 6 - 8 weeks - forever I guess. That makes me think purchased. But if purchased, why aren't you telling them what you want?

I intend to and I know what I want, just wanted to stay reasonable with my request.

Now if it is a rental, did you happen specify cord and plug connectors?

I will specify the cable and the compression lugs. Since the unit goes back-and-forth the plug connector would be restrictive to other users and they would take it off. I am also not too keen on a 360/400A 'plug' although it may be routine for the mining industry.

Just curious.

ice

Stay cuirous, my friend:grin:.

 

[dbuckley]

Is that compressor not an appliance, which when present connects into some fixed supply point, and thus the connection under discussion is not an "installation"?.