Consumer unit query

[jurassic sparkk]

Old shower circuit removed on consumer unit today. I isolated the Cu at the main switch and triple checked for deadness. Checked with a voltage approved tester. Removed the old MCB and associated wiring.

However it has come to my attention that the (32amp) ring main has 4 wires coming out of it. I am quite concerned, it should be only two right; only if someone has spurred a socket from it however this is not the case.

There are only 2 MCB's in this CU
1) 32 amp for the entire ring for the house
2) 6 amp lighting circuit.

The ring is covering the entire house and out of the four wires; three are going upstairs and one is going under the floorboards (two rooms) (first floor).
Could it have been DIY dave who installed this CU. Its a old 3871 type.

Thank you.
Ps this is not my original account.

 

[Taylortwocities]

Sounds like there's an original ring plus two spurs coming from the MCB. Impossible to tell without doing some on site detective work.
Are all the conductors of the same size? Maybe one is powering the cooker?

Sounds as like thats a v old CU with no RCD protection. Probably long overdue for updating.

 

[EFLImpudence]

However it has come to my attention that the (32amp) ring main has 4 wires coming out of it. I am quite concerned, it should be only two right;

No.
Could be a ring and two spurs or two rings - acceptable.

only if someone has spurred a socket from it however this is not the case.

How can you be sure?

There are only 2 MCB's in this CU
1) 32 amp for the entire ring for the house
2) 6 amp lighting circuit.

Ok. Do you mean that is all there is or other circuits are not MCBs?

The ring is covering the entire house and out of the four wires; three are going upstairs and one is going under the floorboards (two rooms) (first floor).

Ok.
Presumably the one going under the floor boards is one leg of a ring but that does not help with the other two.

Could it have been DIY dave who installed this CU. Its a old 3871 type.

How can we possibly know that?


If you know how to test the circuits then you can determine what is what; if not, you will need an electrician.

 

[jurassic sparkk]

No electrical cooker has been installed here. All relying on gas.

I think it is some bodgery, and it is to do with the kitchen.
The kitchen floor is concrete and the consumer unit is oblique to the kitchen and I can not see any part of the ring going to the kitchen.
What I think is, its two cables going upstairs which is a real ring and two radials (lets call it) are going to the first floor including the kitchen.

 

[Taylortwocities]

What I think is, its two cables going upstairs which is a real ring and two radials (lets call it) are going to the first floor including the kitchen.

If it is 32A, then if it were two radials then they would have (supposed) to be in thicker cable. Thats why I have asked you

Are all the conductors of the same size?

 

[jurassic sparkk]

Yes, all are 2.5mm

 

[EFLImpudence]

Two spurs in 2.5mm² would be alright - or two rings.

 

[Murdochcat]

If it’s a 3871 breaker board then it’s well overdue a check and update

Suggest this to your customer is my advice

 

[jurassic sparkk]

No.
Could be a ring and two spurs or two rings - acceptable.

Ermm, One part of the ring went under the floor (presumably serving the downstairs ring) then comes out from the floor from the other side, then goes upstairs with the following 2 cables..

I don't get it cos this ring supposed to be serving the whole house, why did the previous guy not daisy chain it from above to below, makes testing a long day

 

[Taylortwocities]

why did the previous guy not daisy chain it from above to below,

Untitled

• Taylortwocities
• 17 Apr 2008
• 30

Blast from the past

 

[EFLImpudence]

I don't get it cos this ring supposed to be serving the whole house,

Why is that?

 

[jurassic sparkk]

The setup is like this the red wire on the left goes under the floorboard and the red one on the right go upstairs with the 3 other wires shown in the image.

 

[EFLImpudence]

The ring is covering the entire house and out of the four wires; three are going upstairs and one is going under the floorboards (two rooms) (first floor).

Now we have five.

Test to determine which are rings.

 

[jurassic sparkk]

Yeah - four at the mcb.
5 with the other cable included.

 

[jurassic sparkk]

Before testing though I can say it is something to do with the kitchen as I don't see no wires going to the kitchen even though there is four sockets there.