CU change - ring on end of radial

[Lurch]

But, it still does not conform to regs therefore should be noted on the cert as such, which has already been stated.

And what would you note, as you still haven;t said why it doesn;t comply yet.

 

[initforthemoney]

You are correct i didnt say why, although i did give a page number of the regs.

Page 362

 

[Apache]

You are correct i didnt say why, although i did give a page number of the regs.Page 362

Sadly I don't have a copy of the BRB.

Should you have a large shed you might take a feed out in 6mm and then fit a 2.5mm ring on the end. How is that any different?

 

[spinlondon]

You are correct i didnt say why, although i did give a page number of the regs.Page 362

That's an informative appendix, that shows variations on a standard RFC.

Doesn't have any Regulations in/on it.

 

[Lurch]

Oh, that's what's on page 362, my books in the car so not looked yet. Think that's that finalised then, no objections from anyone.

 

[initforthemoney]

Oh, i give up.

And i get infractions for suggesting bad practice headbang

 

[the_mouse]

hi,

wouldnt the 6mm be technicaly a distribution circuit and the the ring the final circuit? if so would the OP's set up contavenne reg 314.4?

"where an installation comprises more than one final circuit each circuit shall be connected to a seperate way in a distribution board. The wiring of each final circuit shall be electrically seperate from that of every ther final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated"

Just trying to learn!!!

 

[spinlondon]

I guess you would have to consider the definition of a circuit.

If both the distribution and the ring part are both protected by the same protective device/s, then they must be part of the same circuit.

 

[batty]

It is not a conventional circuit but is done many times when consumer units are moved etc. As long as the join is either accessible or has maintanance free joint I cannot see you are breaking any regulations. It would not be easy testing it though unless you could get to the join so it is not an ideal situation. I can see this thread being a 10 pager with no real answer.

 

[PC Electrics]

The only question posed in the OP was

Is it okay to proceed with the CU change and just note this as a departure?

I believe this question has been answered. To recap: yes and yes.

 

[Chr!s]

It would not be easy testing it though unless you could get to the join so it is not an ideal situation

I see no issues with the testing of this type of circuit.

 

[Chr!s]

Precisely. I know there must be a JB somewhere, I just don't know where yet

Dave, i think pc's given you the answer, if the circuit tests ok do you need to find the Junction box/connection point?

 

[Chr!s]

And i get infractions for suggesting bad practice

Just because a circuit differs from a standard circuit arrangement this does not mean bad practice has been carried out.

 

[Chr!s]

hi,wouldnt the 6mm be technicaly a distribution circuit and the the ring the final circuit? if so would the OP's set up contavenne reg 314.4?

"where an installation comprises more than one final circuit each circuit shall be connected to a seperate way in a distribution board. The wiring of each final circuit shall be electrically seperate from that of every ther final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated"

No the 6mm wont be a distribution circuit, its a final circuit.

 

[initforthemoney]

Just because a circuit differs from a standard circuit arrangement this does not mean bad practice has been carried out.

So a 6A lighting RFC will be ok then?

Back OT, how you would record all your dead test results, cable sizes etc???

 

[Andy™]

So a 6A lighting RFC will be ok then?

nothing wrong with a ring for lighting... not conventional, but nothing dangerous

 

[Chr!s]

Back OT, how you would record all your dead test results, cable sizes etc???

The same as you would normally

 

[kme]

Can we just point out, for the benefit of those on whom this hasn`t dawned yet:

You can test the ring at ANY point - take a DSO off the wall, and test the ring at that point.

If the readings are satisfactory, you *could* make a note of the fact that there may be a junction box under the floor, where the ring is connected to a 6mm feed; however it is ALSO possible that the 6mm is connected to the ring in the back of a socket - unlikely, but possible, dependant on the terminals.

Apache - you are right, something HAS been said regarding this, a long time ago. I`ve done it, and have no issues with it. All cables are protected, and the list of standard circuits given in the BRB does not preclude the use of other methods.

KME

 

[Chr!s]

Can we just point out, for thebenefit of those on whom this hasn`t dawned yet:You can test the ring at ANY point - take a DSO off the wall, and test the ring at that point.

If the readings are satisfactory, you *could* make a note of the fact that there may be a junction box under the floor, where the ring is connected to a 6mm feed; however it is ALSO possible that the 6mm is connected to the ring in the back of a socket - unlikely, but possible, dependant on the terminals.

Spot on:Salute

As kme has explained we can test a ring at any point.

The 6mm we can treat as a spur from the ring in effect, so if we test the open end of the 6mm and subtract the ring resistance we will be left with the resistance of the 6mm Circuit.

So if we divide that resistance by the Resistance/ meter we can also find the length, which we can use to help find the Connection point.

 

[tom1]

Can we just point out, for the benefit of those on whom this hasn`t dawned yet:You can test the ring at ANY point - take a DSO off the wall, and test the ring at that point.If the readings are satisfactory, you *could* make a note of the fact that there may be a junction box under the floor, where the ring is connected to a 6mm feed; however it is ALSO possible that the 6mm is connected to the ring in the back of a socket - unlikely, but possible, dependant on the terminals.

Apache - you are right, something HAS been said regarding this, a long time ago. I`ve done it, and have no issues with it. All cables are protected, and the list of standard circuits given in the BRB does not preclude the use of other methods.

KME

did this the other day, cpc twisted together in one sleaving buried deep in the cu behind a load of cable, dissconected it from earth bar and did testing from a socket