How far from the ring can an FCU be

[IJWS15]

Am adding some sockets in the kitchen. There is already a single beside a redundant tv aerial point and plan is to link to this.

On investigation the cable to the socket is a spur taken directly from one of the ring circuits at the CU (about 10 feet away in the garage) and wasn’t put in by the builders as the sheath is grey rather than white.

Plan is to use existing cable from CU to an FCU and then on to two double sockets so everything downstream of the FCU is protected by a 13A fuse. There is a spare way on the CU but there is no fuse carrier and it is a 70s MEM unit with rewirable fuses.

Medium term (6months) we intend to get the CU changed and this would probably get its own breaker. Longer term (12-24 months) the kitchen will get redone ant it would be absorbed into the kitchen ring properly.

Now the FCU will be about 2 metres away from the CU so that run will only be protected by the 30A fuse - is this OK?

 

[morqthana]

There is a spare way on the CU but there is no fuse carrier and it is a 70s MEM unit with rewirable fuses.

Is there an RCD?

 

[EFLImpudence]

Now the FCU will be about 2 metres away from the CU so that run will only be protected by the 30A fuse - is this OK?

If the cable can withstand any short-circuit or fault current, then yes.

Why not just use the appropriately rated fuse (wire) or cable?

 

[IJWS15]

Disconnected it at the CU to reroute cables and realised the answer was staring me in the face.

There is a 15a fuse supplying two sockets in the garage, will connect it there.

The garage demand is a chest freezer and the occasional power tool, the additional sockets in the kitchen will supply a TV and electric mop (son is a gadget freak).

There is no RCD. Son wants a car charger fitted (hasn’t got around to getting quotes yet) but I warned him that they will probably want to fit a modern CU first.

 

[Murdochcat]

You really need to address the lack of RCD protection on your sockets as it’s been mandatory for a very long time

 

[JohnW2]

You really need to address the lack of RCD protection on your sockets as it’s been mandatory for a very long time

"Mandatory"?

 

[IJWS15]

We have a couple of portable RCDs for the risky jobs (lawn mower, power tools) but a whole house RCD has disadvantages (FiL had one) so RCDs can wait for the new CU.

AIUI it isn’t mandatory but a new CU will need to comply with current regs so will have them. Previous owner was a real amateur and we have renewed wiring to a room stat that was wired in twin & earth using the earth as a switched live and the loft lighting has been done in 2 core flex so there is no earth, there was a shed fed in twin & earth 30 yards from the house and a greenhouse also fed in twin & earth both disconnected.

 

[flameport]

but I warned him that they will probably want to fit a modern CU first.

More likely is that they will install a tiny extra consumer unit just for the EV, and leave all of the rest exactly as it is.
Waiting for some future event where a new CU might be needed will not result in one being installed.

so RCDs can wait for the new CU.

Your 'new CU' should have been installed 25+ years ago.
RCDs for socket outlets likely to be used for items outside have been required by BS7671 since 1991, 35 years ago.
RCDs for all general use socket outlets has been required since 2008, which is 18 years ago.,

While you can keep whatever old installation you have got for ever, if you are intending to add or alter parts of it, then complying with BS7671 is generally required.
If not, then you have only two real choices - use some other equivalent standard (which will contain pretty much the same requirements) or for those large organisations who employ people that can, you write your own set of standards and risk assessments specific to the requirements for your industry.

"Mandatory"?

Technically no, but in reality for most people yes.

 

[IJWS15]

…..
Your 'new CU' should have been installed 25+ years ago.
…...

Ideally, but we had no control over the previous owner. We haven’t been here long.

 

[IJWS15]

Disconnected it at the CU to reroute cables and realised the answer was staring me in the face.

There is a 15a fuse supplying two sockets in the garage, will connect it there.

The garage demand is a chest freezer and the occasional power tool, the additional sockets in the kitchen will supply a TV and electric mop (son is a gadget freak).

There is no RCD. Son wants a car charger fitted (hasn’t got around to getting quotes yet) but I warned him that they will probably want to fit a modern CU first.

The more you look……

There were three connections to the 15 A fuse. The two sockets (2.5) the garage door (1.0) and another (1.0) destination as yet unidentified - I didn’t want to start looking at 6 last night. Looks like the previous owner didn’t know about FCUs.

 

[Murdochcat]

"Mandatory"?

Yes. There are almost zero applications in domestic properties where you can install sockets these days without RCD protection

And given RCDs have been included in CUs for over 25 years, not having RCD protection in a domestic situation now does suggest the CU needs updating

 

[JohnW2]

Yes. There are almost zero applications in domestic properties where you can install sockets these days without RCD protection

You seem to be missing my point. Despite what you write, one can "install sockets these days without RCD protection" - but one may not do that if one wants to be compliant with BS7671. However, as you know, compliance with BS7671 is not "mandatory".

And given RCDs have been included in CUs for over 25 years, not having RCD protection in a domestic situation now does suggest the CU needs updating

I agree totally, but that's not the point.

 

[IJWS15]

I see JohnW’s point but the CU is not getting updated this month and the alternative is an extension from the one existing socket which had a 30A rewirable fuse as protection and a single 2.5 able as supply.

 

[pete01]

I see JohnW’s point but the CU is not getting updated this month and the alternative is an extension from the one existing socket which had a 30A rewirable fuse as protection and a single 2.5 able as supply.

Just do it but don't tell anyone and don't plug the mower into that socket

Im assuming it's your house and not a job for someone else (not read all the thread)

 

[ericmark]

You need an EICR (electrical installation condition report) maybe you can do that yourself, I am not saying you need to get an electrician to do it, but you need to work out, in the next five years, where you want to go. What you don't want to do, is being spending money on a temporary fix.

The EV is the problem, as often one is forced to use selected installers who have to follow company rules, if you're going to get the really cheap EV rates, often no option.

But no good planning to use an existing ring final, only to find it is not actually a ring, and you need to downgrade it to radials, and you have not got the ways in the box. Need to test things first so you know where you are aiming for in 5 years time.