2.5mm Radial Doing All the Sockets

[nlbhoy]

I was called in to a recently finished house extension as the heating wasn't working, plus they needed
the alterations tested for building control.

There was a kitchen extension to the back of the house plus a 2 store extension to the side which was an office downstairs, plus 2 bedrooms and a bathroom upstairs.

The previous spark has done a runner.

When testing the board there were 2x 32a breakers, one being the kitchen and utility ring which is all fine,
when I've carried out test on what appeared to be the second ring I've found that this is actually a radial, one of the legs appeared to be doing nothing, while the other 2.5mm is supplying 25 double sockets, over 4 upstairs bedrooms, downstairs office, lounge and dining room.

This is obviously a substantial area, there isn't likely to be anything power hungry used in these sockets, as it's TV's, computers with the odd hairdryer and vacuum being used.

Would fitting a 20a mcb be acceptable? so a 2.5mm radial on 20a mcb.

I'm a little concerned about the size of the area this is covering.

I'm not sure if this has been like this before the previous electrician had added on to the existing circuits,
or if he's split the ring main in some way were only one leg is now doing pretty much the full house.

Any help/guidance on what best to do here would be great.

 

[Lucien Nunes]

I agree that 20A might not be adequate, but possibly more immediately worrying would be the leg that doesn't seem to be doing anything. It could well be an unfinished RFC with two live cable ends lying under the floor for a socket that was never installed, or a cable completely severed during interior fitout. I would not commit to any particular solution until I had found the dead end(s).

 

[nlbhoy]

I agree that 20A might not be adequate, but possibly more immediately worrying would be the leg that doesn't seem to be doing anything. It could well be an unfinished RFC with two live cable ends lying under the floor for a socket that was never installed, or a cable completely severed during interior fitout. I would not commit to any particular solution until I had found the dead end(s).

I have disconnected this from the DB and had a look to see if anything wasn't working, everything seems to be fine.

I'm back tomorrow so I can have a better look.

 

[Lucien Nunes]

That's my point. A sensible person would have installed an RFC, you have the right number of cables and the right MCB for an RFC, and everything works. The only thing missing is ring continuity...

 

[Flanders]

Have you done a as test on the circiut at its end point to make sure a 20amp Will disconect in time under fault conditions, I no the rcd should cover that but not ideal but as said you nead to make sure it's a radial and not a broken ring

 

[Pete999]

Had a few glasses of vino, so you have 2 32Amp CBs 1 of which covers a 32Amp RFC and the other supposedly covers a RadialFC wired in 2,5mm but with 2 x2.5s connected at the CB.

If that is the case the you have what could be a substantial problem, as someone else mentioned you may have 2x live end floating around somewhere, under the floor, in the ceiling void, buried behind some plaster board or plaster, does the owner know where he/she wanted any sockets but can't find them, maybe hidden behind a chair or cabinet somewhere.

Your best bet would be to start from scratch identifying cables as you go, it shouldn't be that hard to locate the break, the difficult part will be fixing it, go back to basics that's usually the best option, good luck, now where's me glass?

 

[ruston]

Just to add, as you are concerned, On a 20 amp protective device, historically the area is limited to 50m2.
Appendix 15

 

[Paul.M]

Unless I'm reading this wrong, he has 2 x 2.5mm at the CU that should be a RFC. One of them is feeding 25 sockets and the other leg (which has now been disconnected and rightfully so) can not be traced at this moment in time? So no live cable/s are hidden under floor boards/walls etc seen has he discounted the unknown leg.... Sounds safe atm but a bit of time is needed to locate and rectify, hopefully making this back into a RFC?????

 

[Flanders]

Unless I'm reading this wrong, he has 2 x 2.5mm at the CU that should be a RFC. One of them is feeding 25 sockets and the other leg (which has now been disconnected and rightfully so) can not be traced at this moment in time? So no live cable/s are hidden under floor boards/walls etc seen has he discounted the unknown leg.... Sounds safe atm but a bit of time is needed to locate and rectify, hopefully making this back into a RFC?????

He has disconnected 1 Leg at the board but if it's a broken ring there will be another end somewhere so still need to find it unless there is a socket with just one cable in it , but there still could be other joints , as said more investigation required to prove what is what

 

[Paul.M]

When testing the board there were 2x 32a breakers, one being the kitchen and utility ring which is all fine,

One RFC on a 32A mcb tested and noted.

when I've carried out test on what appeared to be the second ring I've found that this is actually a radial, one of the legs appeared to be doing nothing, while the other 2.5mm is supplying 25 double sockets, over 4 upstairs bedrooms, downstairs office, lounge and dining room.

Sounds like a broken RFC?

He then goes on to say:-

I have disconnected this from the DB and had a look to see if anything wasn't working, everything seems to be fine.

I'm back tomorrow so I can have a better look.

To me it sounds like one leg is feeding 25 sockets and the other leg has been disconnect at the CU so only the possibility of one live cable? Now he needs to find the last socket on the radial to locate the possibility of a disconnected live. Simple and quick fault find for the OP.

Take a Zs at every socket, make a note of each reading and at which socket. The highest reading should be the end (unless spurred off like a spider circuit....very possible?). Take a look at the highest 3 sockets and "bell them out". If that does not work, you have 25 sockets to bell out and find the missing cable...... Good luck

 

[mattg4321]

Or find the socket that the spreads have buried.

Any drawings available? Is there a socket not present that appears on the drawing? Possibly near the CU by your description.

 

[Adam W]

Would it cause too much disruption to run a new leg back to the board?

 

[Paul.M]

Would it cause too much disruption to run a new leg back to the board?

He has to find it first. Thats the fun part

 

[nlbhoy]

Would it cause too much disruption to run a new leg back to the board?

Hopefully it doesn't come to that as it would cause a lot of problems.

 

[nlbhoy]

One RFC on a 32A mcb tested and noted.



Sounds like a broken RFC?

He then goes on to say:-




To me it sounds like one leg is feeding 25 sockets and the other leg has been disconnect at the CU so only the possibility of one live cable? Now he needs to find the last socket on the radial to locate the possibility of a disconnected live. Simple and quick fault find for the OP.

Take a Zs at every socket, make a note of each reading and at which socket. The highest reading should be the end (unless spurred off like a spider circuit....very possible?). Take a look at the highest 3 sockets and "bell them out". If that does not work, you have 25 sockets to bell out and find the missing cable...... Good luck

Yeah, that's pretty much it.

I'll do a Zs at sockets and report back tomorrow.

There were a couple of walls taken down to open up for new extension, I'd imagine if there were sockets on any of these walls that the spark would have likely broken in to the RFC at tone of those points.

 

[Paul.M]

Yeah, that's pretty much it.

You painted a good picture, easy to imagine.

I'll do a Zs at sockets and report back tomorrow.

There were a couple of walls taken down to open up for new extension, I'd imagine if there were sockets on any of these walls that the spark would have likely broken in to the RFC at tone of those points.

OMG you are going to have a boat load of spurs with JB's under the floor! Have fun and report back.

Hope it goes well for you.

 

[Adam W]

He has to find it first. Thats the fun part

By the sound of it there isn't one, or if there is it's been damaged beyond use. Finding the last socket should be easy enough, albeit time consuming, but either way ideally a new leg should be run in to make the whole lot a ring, or two radials.

I take it this isn't simply a case of finding the socket, whipping the front off and reconnecting the cables where they've fallen out of the terminals?

 

[Paul.M]

Adam, on a job like this I would get the phone number of the runaway sparky and ask him to come down and have a chat. But that is just me.

The Op unfortunately has a lot of belling out to do by the sounds of it. There will be loads of spurs! Testing this out should be fun.... We have all been there.

 

[DPG]

Really? The original spark is not going to help you here. If you believe that then you probably believe in father Xmas. Saz

 

[madmaz]

It's a ring circuit I'd say, he says it was wired to a 32a he has 25 sockets fed from this circuit no ring continuity, when he disconnected the second leg all 25 sockets still had power, therefore as a start I'd say test this "radial" find the end of line , drop off that socket and see what's going on looks like you've lost the return leg to me

 

[Adam W]

Of course it would be easiest to call the 'runaway sparky' and ask him what he's done, but I personally don't like the idea of the customer thinking I couldn't sort it out myself, even less the idea that I would benefit from the words of someone who has run away from the job, possibly because he realised he was in over his head.

There are unusual problems which take a bit more time to sort out in every walk of life and the customer should appreciate that, and also appreciate you're picking up the pieces of the mess of someone they shouldn't have hired in the first place.

Either that or I've misinterpreted what you meant Paul and by having a chat with him you meant "having a chat" with him - being a southern softie that's not a business practice I'm familiar with. :wink_smile:

 

[LankyWill]

spent 2 days fault finding on some idiots install this week, bloke had screwed his own cables 3 times and failed put in a lighting feed. Its so much harder picking up after someone else, good luck!

 

[Paul.M]

Either that or I've misinterpreted what you meant Paul and by having a chat with him you meant "having a chat" with him - being a southern softie that's not a business practice I'm familiar with. :wink_smile:

On the domestic front (and some commercial) where the customer has been ripped off by "their electrician". That's when I'm in fight back mode". I get their phone number, call them and ask them to come down to their own install & explain WHAT THE HELL IS GOING ON!!!!


A few have "maned up" and come to site, most just run away.

Your customer and their required/requested end result is our target. Cowboys and Rouges need shooting down at any opportunity! It's just personal entertainment to me. I have no problem pulling other peoples rubbish works.

 

[ipf]

All for a completion cert and Part P, is it?
To 'sign off' another person's work isn't correct.....called to one fault and also finding another more serious one. EICR required then, and a chat with building control. Could be a bit of a mess judging by initial problems.

 

[nlbhoy]

Sorry for the late update, just back from long weekend.

Update on the Job...

Went to the job on Friday morning, after opening up and belling out half a dozen sockets we found where the previous spark had tapped in to the RFC, as there was two sockets that had 4 cables, two had been crimped through in the back of both sockets.

All he had done was connect up the wrong ends after breaking into the RFC, luckily we found this and sorted it in under two hours.

Very happy that we found it quickly and there wasn't any live ends underfloors or in walls.

Quick question regarding certificates...

As the client and builder require a certificate for building control, can I issue a "Domestic Electrical Installation Certificate" to the builder and leave the design part blank for other spark to sign?

I've never really had to test someone else's new install before and I'm unsure how best to proceed with this.

 

[Leesparkykent]

Sorry for the late update, just back from long weekend.

Update on the Job...

Went to the job on Friday morning, after opening up and belling out half a dozen sockets we found where the previous spark had tapped in to the RFC, as there was two sockets that had 4 cables, two had been crimped through in the back of both sockets.

All he had done was connect up the wrong ends after breaking into the RFC, luckily we found this and sorted it in under two hours.

Very happy that we found it quickly and there wasn't any live ends underfloors or in walls.

Quick question regarding certificates...

As the client and builder require a certificate for building control, can I issue a "Domestic Electrical Installation Certificate" to the builder and leave the design part blank for other spark to sign?

I've never really had to test someone else's new install before and I'm unsure how best to proceed with this.

No because you will be taking responsibility for the construction and test&inspection of the installation. So unless you can inspect the 1st fix in its whole entirety then you can't possibly tick the required boxes on the installation cert. How do you know cables are in zones and so on.

 

[Octopus]

Sorry for the late update, just back from long weekend.

Update on the Job...

Went to the job on Friday morning, after opening up and belling out half a dozen sockets we found where the previous spark had tapped in to the RFC, as there was two sockets that had 4 cables, two had been crimped through in the back of both sockets.

All he had done was connect up the wrong ends after breaking into the RFC, luckily we found this and sorted it in under two hours.

Very happy that we found it quickly and there wasn't any live ends underfloors or in walls.

Quick question regarding certificates...

As the client and builder require a certificate for building control, can I issue a "Domestic Electrical Installation Certificate" to the builder and leave the design part blank for other spark to sign?

I've never really had to test someone else's new install before and I'm unsure how best to proceed with this.

I would issue them with an EICR and my invoice pronto.

Whether LABC accept it is another question - one that should have been asked before you started IMHO.