Poss To Add Radial Circuit To Fuse Box?

[Harry Bloomfield]

Interesting reading - @flameport advocating complying with the regs and most others suggesting the regs don’t matter.

Just about sums up the UK these days

The regs do matter, but like all things, common sense is important too.

 

[Murdochcat]

The regs do matter, but like all things, common sense is important too.

Yes and adding RCD protection isn’t expensive either

 

[ericmark]

For a hundred years, we managed perfectly well without RCD's.

And we had only TN-S and TT supplies, and we went mad over bonding, and this was reduced, only if we have RCD protection, and the problem is knowing what other trades will do, will they use plastic fittings in bathrooms, or if no RCD use conductive fittings only? Or use links to ensure bonded.

However what is the problem with trunking and a surface RCD socket? This was fitted by a scheme member electrician as part of a larger job, and a compliance certificate issued last year. Not the way I would have done it, but can see no real problem with the installation. I would have used an RCD FCU next to the inverter, but the way it has been done, easy to see still active, and easy to reset. So all in all better than using an RCD FCU.

I would have preferred it flush, but then there would be a problem with buried cables.

 

[flameport]

Which really would be an entirely pointless exercise, don't you think? A relatively expensive RCD installed, to provide protection to one single socket outlet.

The addition of a £20 item so that what you have installed complies with BS7671.

The rest of the installation won't, and the property owner should be informed of that - but whether they have the rest updated or not is up to them.

Anyone with sense, would make the suggestion of protecting the entire installation, for not much more than the cost of protecting that single socket

To do that would involve a new consumer unit, which will be at least 20x more than that single RCD for the extra socket. Could easily be a lot more once the existing installation has been properly inspected and tested.

The only way for it to be anywhere near the same cost would be for someone to shove an RCD on the whole installation without testing any of it. Not a valid or compliant option and never was.

 

[Harry Bloomfield]

To do that would involve a new consumer unit, which will be at least 20x more than that single RCD for the extra socket. Could easily be a lot more once the existing installation has been properly inspected and tested.

The only way for it to be anywhere near the same cost would be for someone to shove an RCD on the whole installation without testing any of it. Not a valid or compliant option and never was.

However, which does common sense suggest is the safer option, ignoring whether it complies or not?

Safety, is far more important, than strict compliance.

 

[ReganAndCarter]

UPDATE>>>>>>>

I managed to add the extra socket as a spur direct from the fuse box - however, unfortunately I may have committed a mortal sin and expect to get roasted. First thing I have to say is that when I switched everything off including the switch on the main fuse holder below the fuse box (also removed main fuse) - there was a surprise I wasn't expecting. When I removed the fuse box's front cover and probed the brass strips going into the box's switch on the right side of box, I found it was still live. I would have expected that switching off the main fuse and removing the cartridge (the unit below the fuse box) would have meant the fuse box was completely isolated and dead? This could have caught me out. Luckily everything else was dead inside the fuse box, but I had to work very carefully so not to touch the brass conductors going in to the switch. I could find no way of isolating it completely.

Anyway, the new 2.5mm T&E neutral pushed into a terminal on the neutral bar no problem, same with the earth pushing into the earth bar - although they both had to share terminals with wires already there. The problem came when trying to push the positive into the terminal on the single 30 amp ring fuse. The two wires already in there are the old T&E - ie. made up of several strands of what looks like steel wire twisted together, unlike modern T&E which is just one strand of copper. Then these two wires to the 30 amp fuse terminal were twisted together and completely filled the terminal. There was no way I could force the new positive in with the two bulky existing wires.

I may have committed a mortal sin, but I didn't know what else to do. Instead I put the positive into the 15 amp fuse for the cooker - as it only had a single wire in it and easily accepted the new wire. I put a note in the fuse box cover to warn anyone who works on the box that the double socket in hall is wired into the 15 amp cooker fuse - not the 30 amp ring fuse as would be expected. Also put the same note inside the new socket to warn anyone who works on it in the future.

Have I done a terrible thing? What would others have done when faced with a full terminal on a fuse connection. Please be gentle!

DSC01911.JPG

• ReganAndCarter
• 1 Mar 2025

Early 60s Fuse Box/Consumer Unit, Etc

 

[JohnW2]

I agree, that wouldn't be in the pro's interest to do that, but sometimes you have to take a more circumspect view, and assess the risks of simply adding the socket, versus not, or adding the socket, rcbo's, and upset of rewiring for an elderly person. We all know what a professional ought to insist it needs, but this is the real world..
Adding the socket, doesn't make the installation necessarily any less safe. Adding the socket, might mitigate the risk of an elderly person tripping over leads trailed across a floor. Therefore, an overall risk assessment suggests that simply ignoring the rules, and adding the socket, is the safer option, in the circumstances, assuming the OP can install it safely.

Quite so. It's perhaps somewhat ironical, even if understandable, that professionals tend to be, or feel, more constrained to abide by rules/regulations, and less able/inclined to apply common sense (assuming they have some), than those who don't suffer fromsuch professional constraints.

 

[Harry Bloomfield]

When I removed the fuse box's front cover and probed the brass strips going into the box's switch on the right side of box, I found it was still live.

Sorry, maybe my fault, I intended to warn you about the input to the main switch remaining live and quite exposed on those old Wylex boards - just a plastic cap over the screws, if they were fitted. Problem was, the thread got diverted down the road of RCD's.

The two wires already in there are the old T&E - ie. made up of several strands of what looks like steel wire twisted together, unlike modern T&E which is just one strand of copper.

That, sounds like it was wired in 7/029, tinned copper, or maybe 7/036 aluminium, during the copper crisis.

I may have committed a mortal sin, but I didn't know what else to do. Instead I put the positive into the 15 amp fuse for the cooker - as it only had a single wire in it and easily accepted the new wire. I put a note in the fuse box cover to warn anyone who works on the box that the double socket in hall is wired into the 15 amp cooker fuse - not the 30 amp ring fuse as would be expected. Also put the same note inside the new socket to warn anyone who works on it in the future.

Not ideal, but it'll be fine. Nowt to prevent you even putting a 13amp socket, fed from a lighting circuit.

 

[Jurassicspark]

UPDATE>>>>>>>


I may have committed a mortal sin, but I didn't know what else to do. Instead I put the positive into the 15 amp fuse for the cooker - as it only had a single wire in it and easily accepted the new wire. I put a note in the fuse box cover to warn anyone who works on the box that the double socket in hall is wired into the 15 amp cooker fuse - not the 30 amp ring fuse as would be expected. Also put the same note inside the new socket to warn anyone who works on it in the future.

Note that the new socket will be limited to 15A.

What's plugged into the cooker circuit right now?

If the socket is supplying a heater or any other high current consuming device while the cooker is turned on the MCB can trip due to a overload. Bear in this mind.

What will the new socket be supplying?

 

[flameport]

(the unit below the fuse box)

That supplies or did supply something else such as a remote garage, the flat upstairs or whatever.
Unrelated to the fusebox above. Both have separate connections to the meter, where some incompetent type has shoehorned both tails into the single terminal and attempted to cover up the bodgery with large quantities of tape.

 

[Harry Bloomfield]

Both have separate connections to the meter, where some incompetent type has shoehorned both tails into the single terminal and attempted to cover up the bodgery with large quantities of tape.

Obviously seen as acceptable to the SWEB, because they added their seal afterwards.

 

[ReganAndCarter]

Sorry, maybe my fault, I intended to warn you about the input to the main switch remaining live and quite exposed on those old Wylex boards - just a plastic cap over the screws, if they were fitted. Problem was, the thread got diverted down the road of RCD's.

Not to worry, Harry. It's down to me to prove it's live or dead, but goes to show that assumptions could be lethal. What surprised me was there is no way of isolating the box. Suppose if any more major work needed to box, you have to call the elec people to disconnect first.

 

[ReganAndCarter]

That, sounds like it was wired in 7/029, tinned copper, or maybe 7/036 aluminium, during the copper crisis.

Don't know when copper crisis was, house was built in 1961. Could be tinned copper, definitely a bright, metallic finish rather than usual copper colour. Bugger getting them into small terminals though when you have more than one wire. Strands also easily break off if you fiddle with them too much.

 

[ReganAndCarter]

Note that the new socket will be limited to 15A.

What's plugged into the cooker circuit right now?

If the socket is supplying a heater or any other high current consuming device while the cooker is turned on the MCB can trip due to a overload. Bear in this mind.

What will the new socket be supplying?

Only the cooker is on the cooker fuse circuit.

The new socket in hall is for a cordless phone (getting rid of the extension cable across floor that was previously powering it), maybe a table lamp in the future. Occasionally a vacuum cleaner, so hardly any draw. Don't envisage anyone plugging half a dozen two bar electric fires into it any time soon.

Won't be too long before the whole place is refurbed and rewired. Apart from bringing electrics up to modern standards, it needs the number of sockets to more than double for modern usage - and unfortunately most of the ones there now are singles. So whole installation is on borrowed time - my addition is just a stopgap.

 

[ReganAndCarter]

That supplies or did supply something else such as a remote garage, the flat upstairs or whatever.
Unrelated to the fusebox above. Both have separate connections to the meter, where some incompetent type has shoehorned both tails into the single terminal and attempted to cover up the bodgery with large quantities of tape.

Hmm, bit of a mystery. Parents bought the place new, and as far as I know the only elec changes since then have been spurring a socket off upstairs bedroom socket to give a socket in the attached garage and updating to more modern meter. Until I added the new socket in hall, nothing else has changed. So that switched box with massive cartridge fuse never fed the garage, upstairs flat (it's a detached house) or anything else. I'm guessing the large quantities of tape on the wires between the fuse box and switched cartridge fuse box below may be original.