Section 607 circuits - 2x terminals

[Barley Twist]

Evening all!

I'm about to re-wire the study which has a number of PCs and other kit with "leaky" PSUs so I've been reading up on the "Regs".

Whilst I *do* understand the rationale behind the requirement for the double earth terminal in double sockets shouldn't there be a similar requirement for all terminals in all sockets in all applications?

If there is a danger of two cables into one screw connector coming loose then surely this applies to all circuits; phase and neutral as well as earth? Whilst the loss of the CPC (earth) could be immediately dangerous surely the splitting of a ring circuit with consequent overloading and localised overheating at the point of the bad connection is also of concern?

If the earth problem is mainly caused by two cables into one screw connector then why does 607 allow single socket outlets at all? [1]

I've had a look at couple of catalogues and dual-earth fittings are only available in double sockets.

[1] and seems to imply that they are preferred as the use of doubles with dual earth has to be an "exception"

Comments? Barley Twist (Please put out the cats to reply direct)

[Lurch]

Hmmm, not always a good idea, it contradicts itself and tends to confuse!!

It's another one of those daft regs, if it's fitted properly a wire wo'nt just 'fall out'. The IEE seem to like giving us daft rules to follow. There are many regs that only seem to make life harder for us sparks and make no sense at all. Quite a few regs seem to be there just to gloss over actual problems. If an installation is done to the regs then it is unlikely cables will just fall out or break of randomly.

That'll probably come in later. Like you say it is just as likely to happen as an earth falling out is.

Eh?

SJW A.C.S. Ltd.

[Chris Oates]

That second earth terminal can also be used to run a 4mm dual earth

IIRC their ruling is that a double socket cannot take more than one high leakage device - doesn't matter with a single

High integrity earthing doesn't help at all when often the cause of the problem is outside the fixed wiring - break in the appliance lead

[Barley Twist]

Good point - hadn't thought through the implications of that - a break in the earth in the lead with moulded-on "plugs" would make for a very dodgy situation if using a daisy-chain type system to power monitor and possible other peripherals.

hmmm - whilst problems should come to light in a PAT test in a work environment the domestic user can't even open up the plug-top any more to check the earth conection - although I suspect that many breaks occur at the IEC connector end where it's jammed up against a wall and turned through 90degrees. Barley Twist (Please put out the cats to reply direct)

[Bob Eager]

I was thinking about this the other day....

If you have a ring final circuit that uses high integrity earth on every sockey, what do you do at the consumer unit?

[Chris Oates]

requirement is to use separate termination for all earth wires in CU

[Chris Oates]

I think we all know that the common problem is loss of external earth & subsequent potential rise of internal earth parts via EMI filter and any VDRs

There may not even be one - put a class II lead on class I gear

IEC connectors are mostly garbage and nastily made ..at work we regularly throw them away as replacing the whole lead is only 80p

I also either block machines out from the wall or fit right angle IEC plugs (which are really sockets)

[Bob Eager]

That's what I'd have thought....so some re-labelling required.