Cannot have a Spur off a spur but can use an extension lead?

[Brian Matthews]

Probably a stupid question but why is it that you cannot (I think) run a spur off a spur but can connect an extension lead with loads of sockets on it? My son needs about six sockets in a new kitchen where there is only one double socket at present. How can it be done? As a matter of interest, we are trying to get an electrician in the Whitehaven, Cumbria area with no success. Are they all too busy?

Thanks

Brian

 

[pc1966]

From left to right the CB's control:

I was going right to left from main switch.

1. Kitchen oven and left hand skts, 2. kitchen RH skts, 3. Gas boiler and upstairs skts (three floors), 4. Living room and lounge skts, 5. some downstairs skts, 6. all lights

#5 seems unlikely it is a 6A MCB so sockets won't hold up much!!!

#2 is odd, could be like my kitchen when an old immersion heater circuit was repurposed as a socket. Are those the sockets you want to extend? If so, and it is wired in 2.5mm (have to double-check that as potentially 1.5mm could be used on a 16A circuit) then replacing with a 20A RCBO and extending as a radial would be reasonable, so long as total load at any time is less then 4.6kW

 

[Brian Matthews]

From left to right the CB's control: 1. Kitchen oven and left hand skts, 2. kitchen RH skts, 3. Gas boiler and upstairs skts (three floors), 4. Living room and lounge skts, 5. some downstairs skts, 6. all lights

 

[Brian Matthews]

Would one of these be suitable 'BRITISH GENERAL FORTRESS 32A 30MA SP TYPE B MINI-RCBO' on a DIN rail mounted fitting. I don't know what this rail fitting means.​

 

[Brian Matthews]

I was going right to left from main switch.

#5 seems unlikely it is a 6A MCB so sockets won't hold up much!!!

#2 is odd, could be like my kitchen when an old immersion heater circuit was repurposed as a socket. Are those the sockets you want to extend? If so, and it is wired in 2.5mm (have to double-check that as potentially 1.5mm could be used on a 16A circuit) then replacing with a 20A RCBO and extending as a radial would be reasonable, so long as total load at any time is less then 4.6kW

I agree that 5 is odd but it is a 6A and IS controlling some downstairs skts. Will have another check tomorrow as to exactly what skts it is controlling. I do need to add another two cct breakers and will use RCBO's. Don't know what type/size to get though. I posted earlier the type that might be suitable. (Do they all tend to be mini ones?)

 

[westward10]

Would one of these be suitable 'BRITISH GENERAL FORTRESS 32A 30MA SP TYPE B MINI-RCBO' on a DIN rail mounted fitting. I don't know what this rail fitting means.​

No it must be a Hager device.

Hager Reduced Height 30mA 6kA Type B 32A RCBO - ADA332G

Get the Hager ADN132 30mA 6kA Type B 32A RCBO at the best trade price with fast, free delivery available from Electrical2Go.

www.electrical2go.co.uk

 

[pc1966]

I agree that 5 is odd but it is a 6A and IS controlling some downstairs skts. Will have another check tomorrow as to exactly what skts it is controlling.

In some cases you would see the old 5A round-pin sockets being used for lights, such as stand lamps in hotels, etc. Using a 6A circuit for 13A sockets is wrong in a number of ways!

I do need to add another two cct breakers and will use RCBO's. Don't know what type/size to get though. I posted earlier the type that might be suitable. (Do they all tend to be mini ones?)

As @westward10 posted it must be the Hager ones. Contrary to common sense and other industry norms, CU do not have standard busbars and so only the manufacturer's compatible ones should be used. This is an issue not just between manufacturers, but also in some cases between generations with the same manufacturer. Looking at you, Wylex!

If you are contemplating changing the 16A MCB for a 20A RCBO you really must verify the cable is suitable, as whoever designed it originally used a 16A MCB for some reason. Quite what it was is not obvious, might have been a previous fixed load like an immersion heater, might have been due to them only having an old roll of 1.5mm in the van. Whatever the reason was is probably ost in the mists of time, so it becomes a job now to determin if the cable is safe for 20A in such a case.

 

[brianmoooore]

Or if I’m understanding correctly you could spur of off the double into a 13a fused spur and put what you like after that point, although probably not a great design in a kitchen if I’m honest….thinking tumble dryer iron kettle toaster…..you’ll soon get bored of that fuse popping….plenty of good sparks on here from your way I’m sure one of em will be happy to have a look ?

If the socket is already a spur, you can't feed from there to a fused spur and then on to other sockets. The fused spur will have to go before the existing socket, then feed that socket and as many additional sockets as you like (disregarding expected loads).

 

[Brian Matthews]

Thanks for all of your interest. I think the best way forward (if I can get a sparky to do the job) is to get a new CU installed. That would save a few problems.

Thanks again, I have learned a lot

Brian

 

[UNG]

One socket in a kitchen when you need six would suggest the wiring may be quite old, the question would then be how many sockets short is the rest of the property and it may be better to consider a full rewire than doing ad hoc minor / major upgrades to an old circuit which may not meet the regs and pass the necessary testing

 

[Brian Matthews]

When I get a new CU, would it be good enough to get one populated with RCD's instead of RCBO's? That would cut the cost a lot. Thinking about Schneider or Wylex ones. Any advice would be greatly appreciated instead of me diving in and buying a totally inadequate one.

Thanks

Brian

P.S. Still looking for a sparky

 

[SJD]

Far better to have a unit with all RCBOs. Then a circuit fault only trips the one circuit, not half the house!

 

[brianmoooore]

One socket in a kitchen when you need six would suggest the wiring may be quite old,

The recommendation for a least six sockets in a kitchen goes right back to 1961, with the release of the Parker Morris report

 

[brianmoooore]

Far better to have a unit with all RCBOs. Then a circuit fault only trips the one circuit, not half the house!

This is true, but insinuates that this is likely to be a regular event. Going by my own experience, with the split load CUs in my own house, a RCD trip only happens every few years or so.
It's DP MCBs that are missing in the UK, which would isolate earth neutral faults on split boards, enabling the RCD to be reset and keep the majority of circuits working

 

[Brian Matthews]

The recommendation for a least six sockets in a kitchen goes right back to 1961, with the release of the Parker Morris report

I should have made myself clear with regards to the kitchen. We have a three story Victorian house. The present kitchen is on the ground floor. My son will be living on the top two floors and the kitchen I was referring to (not very clearly) is to have another kitchen in a first floor room, this is the one with only one skt. Checked the skt last night and it has only two cables in it. So presumably it is not a spur?

 

[timhoward]

I should have made myself clear with regards to the kitchen. We have a three story Victorian house. The present kitchen is on the ground floor. My son will be living on the top two floors and the kitchen I was referring to (not very clearly) is to have another kitchen in a first floor room, this is the one with only one skt. Checked the skt last night and it has only two cables in it. So presumably it is not a spur?

You are right that it is most likely not to be a spur. We can't ever presume!
I'm not trying to be pedantic but it could be:
1 - an incorrectly installed spur leading to another spur
2 - a radial circuit fed from (generally) a 16A breaker or less
3 - part of a ring final circuit that is no longer a ring due to a fault elsewhere.

That said if it was installed to regs at the time, and turning off a 32A breaker stops the socket working then you have an above average chance that it's not a spur and all is ok. But these are some of the reasons we do dead-testing before modifying a circuit, to make sure all is as it seems to be and is still functioning as the original circuit designer intended.