Even with all of the messages that I did recieve, over this topic, I do not think that I actually answered some of them.


[This message has been edited by Trumpy (edited 10-27-2002).]

[This message has been edited by Trumpy (edited 10-29-2002).]

In terms of voltage drop, these figures are derived from the point of supply to the main switchboard.
All general-purpose outlets over here are rated @ 10A, if you need to have a larger appliance on a socket-outlet, you can use either a 15A or 20A socket-outlet, but the S/outlet must be fed from a dedicated circuit, and protected appropriately.
Only a Range/cooker may be run off a 25 or
32A circuit.

I just remembered one question I think wasn't asked or wasn't answered:

What do your switchboards look like?

C-H,
Sorry if you were not replied to, but there
just so many people wanting information.
No worries, however, with regard to S/Boards, it depends on what type of board you are talking about.
In Domestic Installations, a switchboard,
must be only of a type that MCB's(Minature
Circuit Breakers), can be fitted to, this is a breath of fresh for us guys over here, that have had to deal with porcelain fuse-holders, carrying a simple tinned-copper fusewire.
Wearing Live-Gloves, when replacing these fuses, is a requirement, if there is still a fault on the circuit.
Commercial and Industrial boards are normally made up by specialist switch-board builders, they do a really good job, this is important, if you have a 400V, 1000A sub-
main board to wire and test.
Sorry, but I can show you no pictures of the quality of the workmanship, it's impressive.

Believe you me C-H,
us younger Electrical people, are exposed to all of the sins of our forebears.
Ever worked on a switch-board made out of solid marble, Two inch thick, and to install a single MCB,safebase, takes about 30-45 minutes, once you have drilled all of the holes with a Hilti Hammer Drill,and trying not to split the marble, it's hard going, we are expected to work on really old installations, over here, to re-wire them takes ages.
I had an install, a couple of weeks ago, where I split the whole board into five pieces, marble for you,thank God the power was turned off.

Marble??!! Don't think I've ever come across that before!

We do still have a surprising number of old 1920/1930s boards in use, polished wood cabinets, often with a glass front and the standard rewireable porcelain fuse carriers.

Who uses a hilti to drill in marble? Why don't you use a special drill bit for marble without hammer function on?

I’m feeling on firmer ground here. Marble, essentially a highly cooked and recrystallized limestone, is a relatively soft rock hence it is cut into slabs and polished for the back of old switch boards amongst other things. My advice would be to drill it quite slowly using a carbide glass or tile bit which has the shape of a spade (as in cards not garden). Failing this, or as you penetrated deeper, I would switch over to a standard carbide tipped masonry bit with no hammer and still drilling slowly.

Lubrication would help but I see two problems here: a) the board is probably being drilled in situ and is therefore vertical and b) water, the best lubricant, does not mix well with a wired up switch board. Using light lubricating oil would be a good compromise. If it was possible to drill the marble off the wall when flat, I would build a modelling clay dam around the drill site, fill it with water and go at it slowly with the bits mentioned above.

Thanks guys, for the advice on the drilling of marble switchboards, we normally don't do too much with these types of boards, we normally advise that they be replaced as we have a saying over here, with respect to old marble or Zealite switch-boards: If theres marble on the board, then there's rubber in the roof.
Never been proved wrong, yet.
Basically, the need for MCB protection, makes a board replacement worthwhile.

Ever wanted to find out about our Regs, ECP's(Electrical Codes of Practice),
check out this website: www.ess.govt.nz
It should show you anything that you want to know, about our really warped Regs system.

That's nice. Everything on-line. Seems to be more comprehensive than the Swedish. Wonder if they accept that you use NZ code here?

C-H,
The NZ Electrical people are taking the IT path, these days, instead of making screeds of paper Regulations, it is simply being put straight On-Line, it is actually quicker to find it on their site or with the CD-ROM's they provide to us FREE, than flick through a mountain of paper folders, etc.
Saves on wood too!, gotta be good for the environment.

Paul,
You mentioned that you have come across wooden cabinets used as switch-board enclosures, in older installations.
How do you get around the requirements to have a enclosure with the need to have a Fire-Proof medium around the whole switch-board area?, especially when Porcelain fuses are used?.