My Complete DIY Rewire

[JohnW2]

Your comments relate to the relationship between the CCC of the cable and the choice of protective device, not to the choice of a radial or ring.

That's true but, to be fair, the only really contentious aspect (and main perceived advantage - other than redundancy of CPCs ) of ring finals is the 'dispensation' which allows a cable to be protected by an OPD with an In greater than the cable's Iz/CCC. In the absence of that 'dispensation' (i.e. if all 32A sockets circuits had to be wired with ≥4mm² cable), I doubt that many people would bother (or think) to wire those circuits as rings, would they?

Kind Regards, John

 

[ban-all-sheds]

Really?

You really think that if you went to the IET and said "I've an idea...

No, of course they wouldn't accept it. They would of course send you away to BSI, to present a proposal to JPEL/64 for an amendment.

Sigh.

If you went to the IET and/or the BSI and/or JPEL/64 and said "I've an idea. If we introduced fused plugs, and fused connection units, and as long as we specified that cables had to be OK for 20A, and as long as we told people that they had to make sure that they didn't overload sections of it, and as long as we told them not to have more than one socket on an unfused branch, and as long as we made sure electricians did some extra testing to confirm it was sound, we could use 2.5mm² cable wired in a ring from a 32A breaker", do you think that they would say "Brilliant idea, stillp - we cannot see any flaws in it, and we'll change the regulations to allow it at the earliest opportunity."?

 

[stillp]

I doubt that many people would bother (or think) to wire those circuits as rings, would they?

Most would, if that was what BS7671 required.

 

[ban-all-sheds]

What would the advantage(s) of such a circuit over a 4mm² 32A radial be?

 

[stillp]

Redundancy.

 

[deadshort]

I don't have any casual relationships! Don't even reply …… It's humour


DS

 

[deadshort]

Just a wee reality check, if you have any doubts about the Uk wiring system, take a trip to USA, bloody horrific Wendy House wiring systems, fisher price plugs

In the absence of quotes, I'm not sure whether that was directed at me - but if it was (it did immediately follow my post), then you must surely realise that you are 'preaching to the converted'?

We have the best and safest wiring system in the world when installed by professionals.

Indeed, and even when installed by non-professionals, if it's done properly!

Kind Regards, John

No John not directed at you at all.

Regards,

DS

 

[JohnW2]

I doubt that many people would bother (or think) to wire those circuits as rings, would they?

Most would, if that was what BS7671 required.

Well, yes, but (as you know full well!) that's obviously not what I was thinking about. I was referring to a hypothetical situation in which BS7671 said that 32A sockets circuit has to be wired with ≥4mm² cable, but that the designer had the choice (with no preference mentioned by BS7671) as to whether to wire as a ring or radial. In that situation, despite the redundancy offered by a ring, I somewhat doubt that many would 'bother' (with the ring) - but I may, of course, be wrong!

Kind Regards, John

 

[JohnW2]

No John not directed at you at all.

Fair enough - but it did give me the opportunity to indicate that I totally agree with you - other than with your implication that UK wiring system is the 'best and safest in the world' only if installed by professionals

Kind Regards, John

 

[stillp]

I doubt that many people would bother (or think) to wire those circuits as rings, would they?

Most would, if that was what BS7671 required.

Well, yes, but (as you know full well!)

I have no idea what you were imagining John, and whether you had included BS7671 in your hypothesis.

 

[EFLImpudence]

I was referring to a hypothetical situation in which BS7671 said that 32A sockets circuit has to be wired with ≥4mm² cable, but that the designer had the choice (with no preference mentioned by BS7671) as to whether to wire as a ring or radial. In that situation, despite the redundancy offered by a ring, I somewhat doubt that many would 'bother' (with the ring) - but I may, of course, be wrong!

By 'ring' in this instance you, presumably, mean wiring the 32A circuit in 2.5mm².
I don't think anyone would choose to do that if they had never heard of our ring circuits.

However, because of length of circuit and location of the appliances (probably lights) some commercial circuits may be wired in a ring to reduce volt drop but it would never be accompanied by a reduction in the OPD rating to less than the CCC of the conductors.

 

[JohnW2]

I was referring to a hypothetical situation in which BS7671 said that 32A sockets circuit has to be wired with ≥4mm² cable, but that the designer had the choice (with no preference mentioned by BS7671) as to whether to wire as a ring or radial. In that situation, despite the redundancy offered by a ring, I somewhat doubt that many would 'bother' (with the ring) - but I may, of course, be wrong!

By 'ring' in this instance you, presumably, mean wiring the 32A circuit in 2.5mm².

NO. Read what I wrote. I was talking about a hypothetical situation in which there was no 'dispensation' for rings, so that In≤Iz≤Ib had to be adhered to for any circuit - so that a 32A sockets circuit (whether ring or radial) would have to be wired in ≥4mm² cable. I was suggesting that, if that were the case, I suspect that most would not bother with rings - at least in domestic situations.

However, because of length of circuit and location of the appliances (probably lights) some commercial circuits may be wired in a ring to reduce volt drop but it would never be accompanied by a reduction in the OPD rating to less than the CCC of the conductors.

[I suspect you got that last bit 'back-to-front'] Exactly. As you say, that might possibly be done for VD reasons, but without the In of the OPD being greater than the CCC of the cable.

Kind Regards, John

 

[EFLImpudence]

However, because of length of circuit and location of the appliances (probably lights) some commercial circuits may be wired in a ring to reduce volt drop but it would never be accompanied by a reduction in the OPD rating to less than the CCC of the conductors.

[I suspect you got that last bit 'back-to-front'] Exactly. As you say, that might possibly be done for VD reasons, but without the In of the OPD being greater than the CCC of the cable.

A lot of negatives.

What I meant (unlike THE ring circuit) was that if it was chosen to make a ring, for volt drop reasons the OPD would remain the same rating as the radial would have been.

Edit - Bugger - I did it again. I think I'd better go to bed.

 

[JohnW2]

What I meant (unlike THE ring circuit) was that if it was chosen to make a ring, for volt drop reasons the OPD would remain the same rating as the radial would have been.

Fair enough.

The OPD would not be reduced to make it similar to THE ring circuit, which is what I thought you originally meant.

That's still 'back-to-front', isn't it? If you wanted to mirror the situation of the standard ring final, you would surely increase, not reduce, the In of the OPD (as compared with a radial using the same cable) wouldn't you? In other words, for example, if you had a 2.5mm² radial protected by a 20A OPD and then added a return path to CU to turn it into a ring, you would (or could) then increase the OPD to 32A.

Edit: Aha, gottcha - before you deleted it

Kind Regards, John

 

[skotl]

This is the worst example of diynot/electrics.

The clearly incompetent and irrational OP had not been seen for a couple of pages yet you're arguing academic points that he didn't even raise.
The OP is so magnificently out of his depth that I would have thought there would be enough material in trying to address his failings.

All of the other discussions re ring finals etc should have been conducted on a separate thread.

I honestly think that if you want to discus academic points then you should create new threads for these discussions and not digress from the core point of the original thread.