Re: NIC EIC needed to work in the kitchen?

Do you have any idea how many people died from electrocution in the UK every year?

For a new house or a full rewire the extravagant system you describe is adequate although why you would want to put any lighting circuit on an RCD is puzzling. For existing wiring there are still far to many "qualified" electricians conning people into having consumer units alone replaced (Much professional trained sucking of teeth and muttering "Can't pass that mate - not compliant are you?"). When the do the lucrative and simple CU replacement they often leave lights on RCD's and tell the hapless owner they are now "safer".

Reply to
Peter Parry
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Peter Parry wibbled on Wednesday 25 November 2009 09:07

You *have to* if working to the 17th, unless you like doing SWA, MICC or screwed steel conduit for all your switch drops ;->

Or your walls are thick and you like chasing cables >2" deep...

Reply to
Tim W

Ignoring the tripping of an RCD in a fire etc, my feeling is you're more likely to 'get a shock' when changing a bulb than any other similar task around the house. Of course 'more likely' is still a tiny amount.

Reply to
Dave Plowman (News)

Unburied plastic conduit on the surface?

Reply to
Andy Dingley

It's still the only outlet which has unshrouded live terminals.

It's a shame every DIYer didn't write to the IEE at the time of all this. The majority of it's members opposed the support given to legislation and the institution has since renamed itself in shame.

Reply to
Fredxx

:-)

Owain

Reply to
Owain

The 17th edition does not support "whole house" RCDs. Were talking multiple independent RCDs here.

Reply to
John Rumm

Why protection does MICC afford to drill bits, screws and nails?

Reply to
Fredxx

Dave Plowman (News) wibbled on Wednesday 25 November 2009 10:31

Hager/Ashley make a nice BC fitting that isolates on the turn so the pins are dead by the time the bulb comes out.

If the meddling government wanted to do something useful, they could mandate all fittings did that.

Not that (m)any people die from such accidents - but is is an obvious improvement with no disadvantages for the user, like shielded 13A plug pins and shuttered sockets.

Reply to
Tim W

About the same as conduit.. none. However it does earth the drill bit/screw/nail and stop you getting a serious shock (in most cases). You can pass the protection requirements with some earthed foil around the cable.

Reply to
dennis

Fredxx wibbled on Wednesday 25 November 2009 11:44

Mechanically - about as much as SWA. Screwed conduit is tough but an SDS will probably go through it.

The point which is often missed with MICC and SWA, is the primary purpose of the earth shield (armour or copper jacket) is to ensure that any metal implement going through is earthed before it hits a live conductore, thus protecting the person. Secondly, hitting the live conductor will trip teh circuit protection.

The secondary benefit is the toughness of the armour or copper sheath - but it is not presumed that these are indestructible.

Reply to
Tim W

Andy Dingley wibbled on Wednesday 25 November 2009 10:42

Well, there is that option too. Clipped cable too if you like :)

Reply to
Tim W

Mechanically, little. However it ensure you get an earth fault when you do nail through it, and that cuts the power off.

Reply to
John Rumm

Part of the argument with BC holders is that it is very difficult to get enough contact area on the terminals, and also difficult to get a particularly unfavourable conduction path across the chest to actually be that much of a risk.

Reply to
John Rumm

It's what I'm installing in the workshop. Steel conduit's a pain and I don't want anything buried, because of future access. A workshop I used a while back was built from hollow cement blocks and had cable inside the block voids. Now _that_ was a pain to work with.

Surface plastic is also a reasonable approach for some kitchen work, as you can hide it behind fitted units. It gives easy flexibility for appliance placement.

Reply to
Andy Dingley

Andy Dingley wibbled on Wednesday 25 November 2009 14:06

Indeed.

Due to location of isolator switches above the worktop and sockets below, plus random holes for plumbing, it was a pain to try to conceal the final cables to the appliance sockets in an IEE approved zone. And teh socket poisitions weren't obvious without the plumbing being in place.

So I brought 20mm round out to the surface from the flush isolator boxes (offset bend in conduit) and left them at tails.

Now that the plumbing's in, it has become clearer where the sockets can go, so I'll continue in surface round tube (where I can route it anyway I like) and finish in metal clad sockets. Given the number of pipes knocking around down there, 3 more won't make any difference :)

I have a similar problem round the back in the utility area due to flat roofs and lumps of timber - nearly impossible to find a buried zone that works, other than long horizontals within 150mm of the ceiling, so the boiler and washing machine will probably get surface cable, but probably in mini trunking rather than conduit.

Reply to
Tim W

27 deaths in 2002, of which around 18 were workplace incidents. Presumably a couple were individuals removing themselves from the gene pool by climbing onto railway overhead supplies and that leaves a handful due to accidents in the home.

That is around 1 in 100,000 deaths a year being caused by electrical accidents at home. It does seem that an awful lot of effort seems to be going into trying to reduce that very small proportion still further. Is that actually cost-effective, compared to say spending a similar amount of money on improving road safety (3000 fatalities a year)?

Reply to
GB

Well to get brownie points for improving road safety the Government will need to spend lots of money but to improve the electrical safety of our homes the government just tells us we have to spend money to comply with Part P.

Reply to
Mike Clarke

extravagant and adequate in that sentence are non sequitor :-)

BS7671-2008 requires... #1 - ALL cables RCD protected unless

- a) surface run over entire run (no chance due to aesthetic devaluation)

- b) buried >50mm from finished surface (no chance due to BR "A" limits on wall chase depth)

- c) comply with 526-06-06 (no chance unless BS8436 which is 7x the price of twin-&-earth)

Thus in effect all circuits must be RCD protected.

#2 - A fault on one circuit should not cause unnecessary disconnect of others (314.1)

- Whole House RCD is not permitted

- Lights all on the same RCD is not permitted

- Lights must be distributed so Up on RCD#1 and Down on RCD#2

The key problem of RCD (apart from cost) is eliminated.

BS7671 17th practical compliance:

- Distribute circuits over 2 RCD (=A340 extra)

- Put Lights Up & Down on their own RCBO (=A325+25 extra)

I myself would break away Hall and put it on Smoke (=A325).

Why have lights on RCD? #1 - Outside lights wired off interior, fittings leak, metal stepladders #2 - Many houses have light circuits without CPC, but technically Class-1 fittings

RCD will not generally help with ES or BC light fittings because LN across the fingers will throw someone off a stepladder or downstairs, but will not trip the RCD unless sufficient current flows to earth. Incidentally 13th regs did state you can only fit class-1 lights to a light circuit without CPC *if* the floor was not concrete (conductive).

Nuisance tripping of lights came about due to Type-B trip characteristic compared to slower cartridge fuses & fuse wire.

Putting lights on RCBO avoids other circuits taking out lights (hence some believe 314.1 actually requires lights on dedicated RCBO).

I still suspect the Distribution Network want all RCD. #1 - Removes the cost of maintaining low Ze #2 - Removes the cost of providing/maintaining any Earth Terminal

The reality is that FEW lives are lost due to FIXED wiring.

The future reality will be when RCD begin to fail - 7% failure rate is due to dust, humidity & lack of regular testing (ok that covers domestic quite well!). Now consider 3x RCD or 12-16x RCBO, the increase in RCD just created complacency which since most accidents are due to human error just invites more accidents downstream. Part P blocking people fixing damaged wiring hasn't helped safety statistics, like Part M idiot 45cm socket height hasn't helped trip statistics.

Just be glad RoSPA didn't write regulations... ... the problem with contractors milking is however serious - however nice paper trail & indirect taxation for Gordon, together with fees for glass house certifying bodies populated by corrupt statisticians & marketeers

Reply to
js.b1

So 9 for domestic.

How many of those were from portable appliances v fixed wiring? :-)

Reply to
js.b1

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