Any electricians on here – advice needed

[AjohnwParticipant @ajohnw51620]

I don't think it's much of a qualification Dave – it seems to be an open book exam so the main problem is the cost of the book.

All of this area was discussed long ago by various fellows of the IEE, usually ones in senior positions. All of it seems to have got through and there are reasons for some of the changes – earth bonding on water pipes for instance had to go due to plastic pipes. Gas pipe bonding in case there is a short to them. It's all aimed at reducing fire risk really. Fully protecting people from electrocution isn't that easy. Most of the information in that area has been gained from pigs.

Bonding may have a catch. Several options were discussed. Long runs needing heavier cabling or can be spiked periodically or just spikes can be used. This may just apply to factory wiring but I'd guess that this aspect is buried in the regs some where. I did have the lot on cd but it would be 4 ot 5 years out of date now.

In one incarnation I used to be called in to do odd jobs for one of the said Fellows.

John

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[Martin KyteParticipant @martinkyte99762]

**LINK**

Should tell you all you need to know about earthing systems.

Things do move on as times and equipment change. With residual current safety devices earth bonding is less of a priority than it once was. For example it is no longer desireable to earth bond water pipes and metalwork within kitchens as the less likely it is to both connect yourself to a live conductor and to a good earth at the same time the less likely you are to suffer fatal shocks. In Bathrooms where there should not be any chance of coming into contact with live conductors the opposite applies.

Martin

[AjohnwParticipant @ajohnw51620]

The problem with the web is that what is really needed is this

**LINK**

Google for it and various other books which don't have the same coverage will pop up. It seems that the IEE also produce a guide for electricians. It seems to be hard to find but they now seem to be the onsite guide and published by the IET.

John

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[EmgeeParticipant @emgee]

Posted by Martin Kyte on 10/11/2016 12:16:20:

Well this is what I did.

10mm SWA underground to the workshop (6mmwill be fine I always go for overkill)

Feed taken from Consumer unit in the house after the Main Breaker but before any RCD's (Split box). 10mm is current protected by MCB at this end…

Martin, If your SWA is connected to the output of the 100A DP switch the PSCC protection you are relying on for your 10mm SWA is the supply authority fuse, your cable may not be protected as you believe it to be against such overload. This cannot be calculated without knowing the fuse type/size, EFLI of the cct and the external loop impedence. You may find a further circuit protective device is required at the source of supply to protect the cable.

Emgee

[Martin KyteParticipant @martinkyte99762]

Hi Emgee

The 10mm runs off a MCB after the breaker and before the RCD protected side of the consumer unit. I thought I said that but maybe it was not as clear as I thought.

regards Martin

[AjohnwParticipant @ajohnw51620]

Posted by Steve Withnell on 10/11/2016 08:26:18:

Whilst here are a few electrically minded folks watching – minor thread hijack. Just had my kitchen re-fitted and the electrician has fitted the power socket for the integrated dishwasher directly behind it, meaning you have to strip the appliance out of the cabinet in order to isolate the power. I've told the electrician that does not comply with the 17th edition… he says it does. Surely he cannot be right?

Apologies for the hijack…

Steve

It looks like the ability to isolate built in things is a should rather than a must. Not read enough yet but I would expect usual spec jargon – shall or must. There is also mention of fused connection units which i would assume could also be a fused socket. Also fitting a double pole isolator switch that can be reached. I vaguely remember seeing some very narrow switches used on kitchen units but can't find any signs of them. They may have been just for lighting anyway.

This is the IET though and I have read that it's more "extensive" than the actual building regs.

John

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[Ed DuffnerParticipant @edduffner79357]

Hi Fizzy,

Your armoured cable will be fine. Protect it with a 45amp MCB (miniature circuit breaker) – the current rating increases slightly for armoured cable. The house RCD will protect the circuit but ask your sparky just to be sure before buying any switch-gear or protective devices.

I would suggest laying some bright yellow tape over the top of the cable in the trench that you dig, we used to call it hep-tape.

Regards,
Ed.

[Neil WyattModerator @neilwyatt]

You there Fizzy?

N.

[Ed DuffnerParticipant @edduffner79357]

I think he's outside digging a trench …in the moonlight!

[Neil WyattModerator @neilwyatt]

I think he's busy dissolving one…

N.

[Ed DuffnerParticipant @edduffner79357]

Is that why he's called fizzy?

Ed.

[nigel jones 5Participant @nigeljones5]

I'm here…thanks everyone. What I have at the moment just about scraped through the regs, I have a fused spur from a ring socket to the workshop via 4mm armored 3 core, this goes straight to a double socket and a second 5A switched spur off this for the lights. Some say you shouldn't spur off a spur but the regs seem ok as long as they are fused. Its all clipped above ground, only problem is that when there is a small problem it trips all the downstairs sockets and wifey goes nuts!

[John Stevenson 1Participant @johnstevenson1]

No it's just a typical Fizzy hand grenade post,

Pull the pin, count to 5 then let go and stand back, he's got it off to a fine art.

[nigel jones 5Participant @nigeljones5]

fizzy goes back to being 16 years old and owning an FS1E…them were the days!

[nigel jones 5Participant @nigeljones5]

How very dare you….some of us have been out at work! I endeavour only to provoke lively debate and offer genuine help and advice, I struggled to get any info on the installation on the web – no hand grenades in this thread.

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