ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades U.K. 3-phase service pics

lyle -- See https://www.electrical-contractor.net/ubb/Forum5/HTML/000323.html for a current {no pun..} thread.

Lyle,
I think you may have just cracked that nut there, mate.
Paul was asking a question in the "Photos Submitted For Discussion" Forum about this panel and it's wiring method.
I do know that you are allowed to feed singles through a metal panel, but you have to use a Non-ferrous(brass)gland to do this.

(Oops, must have posted at the same time as Bjarney!)

[This message has been edited by Trumpy (edited 06-01-2003).]

Sorry for any confusion guys. I posted a short version of this in the general photos section for better coverage, but I guess that wasn't such a good idea.

No worries Paul,
But what was the actual violation pertaining to this install?.

yep you cannot take single phase conductors through holes on their own,, this would cause eddie currents..

you must either install them with a neutral or earth cable,, or cut a slot between all three holes.

Trumpy,
Yes, the phase conductors entering through three individual holes in a steel enclosure was what I had in mind.

So what do you do for strain relief and cable protection at such an entrypoint?

Is there some sort of grommet materialthat's sold for when you cut out the steel between the holes and turn it into a large slot?

I assume that three-phase setups in the USA have all three phases and neutral running in the same pipe, through a single entry in the panel and then branched inside the panel out to their respective legs on the switch, right?

I'm sorry I ask this silly question, but 3-phase is a bit over my head...

[This message has been edited by SvenNYC (edited 06-10-2003).]

Sven,
If you are installing single cores through a panel, you have to bring them in through a non-ferrous plate or gland.
This prevents Eddy currents from the wires inducing currents in the panel metal.
Over here we generally cut a large slot out of the metal panel and fit an Aluminium plate over this and then fit plastic cable glands into the Al plate.
You're right about the conduit entries.
We seldom use single cores over here, apart from on really BIG jobs (200-400A+ per Phase), it's a lot easier to run Neutral-Screened into a switchboard(it's round) and this is used 9 times out of 10!.
Not a silly question in the slightest.