House rewiring discussion (please don't stray off the path!)

Posted by: NaimThatTune on 03 September 2005

Learned Friends,

I need to get my house rewired, completely. It's got an old style radial system where spurs fan out from the fuse box, much like spokes of a bicycle from the hub. Some of these have been extended (naughty, naughty) by the previous owner and I want to rip it all up and make it good, up to date, safe and, incidentally, have a dedicated hi-fi supply/maybe CU fitted.

I am, of course, going to use an NIC/EIC qualified contractor for the job.

Eek Eek Given the nature of this topic, please don't anyone mention various modifications/short-cuts/random naughtiness that may cause our gracious hosts to kill the thread. Eek Eek

I have a few questions for those in the know:

*as I'm having the whole shebang redone, is there any need to have two CUs, one for the rest of the house and one for the hi-fi?

* does anyone have experience of the plaited 'Kimber' style cable as sold for mains installations by Russ Andrews? I may blow for this but only if its worth it.

* what are your thoughts on whether an electrician is likely to be happy to install heavy grade (10mm2) cable to the hi-fi area/sockets.

* is it allowable to have conections run uninterrupted directly from the CU to the back of each hi-fi box, terminated just in a hefty IEC plug? Thus there would be no sockets (round pin or otherwise) between the CU and each component. The units would be protected by their own *completely standard* fuses and the protection provided by the CU.

*are there different (legal/sanctioned) types of trips for the CU, such that I could advise/ask the electrician for the lowest impedance ones.

* Earthing - my house has a rubbish earthing system and the metal gas pipes in the road outside were recently replaced with plastic ones - should I compound my internal disarray by proposing we dig up my patio and connect to a dirty great earth rod buried in the front garden?

* I'm wary of using other people for doing decent quality jobs - any good questions I can ask my sparky to determine whether he's a loony or top-notch? I don't mind paying for kwality (hence I use Naim kit) but I don't want to be ripped off by stupid hourly rates or barely adequate work.

*my meter is an old style 'spinning horizontal disc' type - I imagine the advice from the electrician will be to get the power company to change it to a modern digital one. Are these low-impedance/do they inject any noise onto the mains?

*is there anything else I should ask about?

*oh, and do you like the idea of lights inset in the wall up the side of the stairs, say, every third step, or is that just showing off?

What thinks thou? Any tame electricians out there want to give me a few tips?

Best,

Richard.
Posted on: 05 September 2005 by Nime
Wasn't it Pepys who said:

"To employ an electrician is to be robbed" Big Grin
Posted on: 06 September 2005 by custard
The best sockets to use according to my dealer are Crabtree(unswitched).
Posted on: 06 September 2005 by NaimThatTune
Hi All,

Nime - er, I don't get it... is it cos I is from Wales?

custard - ah yes - I'd forgotten about Crabtree - don't Naim use Crabtree plugs on their mains leads these days? (My newer kit is all packed away from the impending destruction so I can't easily check). Maybe there'll be some special synergy! Or maybe not Razz

Cheers!

Rich
Posted on: 06 September 2005 by Nime
Pepys (the diarist) is supposed to have said:

"To take a builder is to be robbed!"

Or words to that effect. (It was a bit before my time)
Posted on: 20 September 2005 by NaimThatTune
UPDATE: I've just had a visit from the electrician (a proper NICEIC qualified one) - and have some good news.

I was previously under the illusion that the existing wiring going to my seperate spurs (my house is all radial without ring mains) would have to be removed and all new ring mains put in.
This isn't the case - the end of the spurs can be reconnected back to the (new) consumer unit and turned into a ring, with new sockets along the way. So that'll save a whole bunch of work, upheaval and expense, so I'm happy on that front. Also, I'd been misinformed when a friend told me that it was against regulations to extend spurs by daisy-chaining more sockets on - that is a myth and its actually fine to do so (this had been done in my house and I was worried about it).

Also, I quizzed him about the 'requirement' for all sockets that 'might reasonably be expected to supply an outside device' (such as a garden strimmer) and he said that that isn't a hard and fast rule - its advice which is wise in most cases but if you have an overpowering desire to avoid an RCD, then that's your decision. (I would avoid the RCD for the hi-fi spurs for impedance reasons but will use them elsewhere).

He didn't bat an eyelid when I mentioned a few spurs dedicated just for the hi-fi, and is apparently used to this kind of request (though normally for providing clean power for phone systems etc).

He confirmed my earth situation as follows: I have a simple clamp onto some water pipes for the plug sockets (water pipes in my street have been replaced with plastic) and I have no earth on the lighting system at all. The power supply company (Western Power in my case) would need to be called (he'll do this when he starts work) and they'll re-work the connection to earth and provide me with a decent PME (Protective Multiple Earth) connection. This should cost just over 50 quid to get done, which sounds like a bargain to me. He sees no need for any kind of earth rod once the power company have (somehow) connected me to a decent earth.

He's also totally happy for me to do some of the build work (holes for back boxes behind sockets, chasing slots for wiring etc) as long as he gets to do the electrical side of things.

So my situation is now:
1) map out where the existing wiring is, produce a plan showing where the existing wiring is and where I want new sockets to go.

2) The kitchen can be done at a later date, and the best way to wire this up is with a seperate ring for the kitchen anyway. He'll leave me with a supply that can be easily connected up to a new kitchen-only ring when I rip out and replace the kitchen.

3) All of the lighting wiring need to be replaced with an earthed system, this will require floorboards to be lifted (bit of a pain as mine are tongued and grooved).

4) One new consumer unit is all that's needed on that front.

5) He's happy for me to specify any brand of parts and even source them myself, so I can have MK or Crabtree sockets no problem and a Memera CU if I should desire it.

Incidentally, he said that it is preferable to keep the old wiring if possible - they tended to use quite chunky copper when the house was built ('62). The only thing to watch for is the insulation thats used - polythene was once used and now the material used is PVC. The problem with the older polythene is that its 'self-combusting' - if you put a flame to it, it will carry on burning once you take the flame away. PVC doesn't do this. 40 year old wiring is not a problem in my case, the sleeving appears to be PVC (though how he could tell just by looking I don't know).

So, not a bad outcome, and the size of the job seems reduced now, though still sizeable it doesn't seem to be such a mammoth task.

Hopefully, some of you reading this may find it useful!

Regards,

Rich.