2.5mm Radials - Existing Domestic Circuits

[SidTheSparky]

Hello people,

Is it common to see a house with two radial circuits instead of rings, each circuit is backed up with 20A fuses, each circuit supplying around 5 sockets outlets, each circuit is a 2.5mm T&E radial?

Kitchen is an extension, with it's own 2.5mm ring for socket outlets.

It's a sweet elderly lady's house. She's thinking of getting a rewire but then won't be able to spend money on mobility aids and some modifications for her bathroom. I'd rather she spent her money on mobility aids and stuff.

The electrics were installed pre-1988. It's all T&E, very pliable and looks well installed - no alarm bells ringing in my head. I'd rather just upgrade her fusboard so she can spend money on stuff that's more important to her at this stage in her life.

The main thing stopping me just upgrading the fuseboard is that I've only ever seen 4mm T&E radials before. That's why I'm wondering whether it was common to do 2.5mm radials at some time in the past and whether it's acceptable to upgrade just the fuseboard. Obviously I'll test the wiring before I come to a final decision.

(Upstairs and downstairs lights are all on one circuit too - not ideal, going by newer standards, but acceptable for an existing installation in my opinion).

Opinions greatly welcomed - thanks in advance.

 

[Zeespark]

Yes thats not an issue.

AndyGuinness

 

[matt.leung]

u have no issues to worry about there...

 

[Hawk81]

all sounds perfectly fine to me.

 

[ianmacd]

You have this the wrong way round. Rings should become history not radials.

As long as they pass the tests they will be fine but you may want to see if she really needs 20A radials and not 16A esp. with the kitchen on a separate circuit.

 

[m4tty]

2.5mm radial on 20a cpd is in brb so all good mate

 

[binky]

came across one house which had a radial socket and seperate light circuit per room. Talk about a large fuseboard ( actually it was 2 boards, one for lights, and one for sockets). Flipping great to work with.

 

[Evans Electric]

Nothing wrong with 20A radials, I do them a lot, specially through bedrooms . As discussed before , some guys think if its not a ring ,its wrong.

We can all get a bit too picky sometimes ,especially when looking at 15th and 16th installations , don't forget they were the bees knees once ,they have not changed only the book has .

 

[sparky999]

As long as it doesnt exceed 50m2 and a ring is 100 and 4mm cable is 75m2 i believe. What if the radial is say nearer a 100m2 but your still under your zs is it still fine and carry on as you are?

 

[a1spark]

As others have confirmed 2.5m radial circuits are compliant. One point to bear in mind though is that there is the possibilty they were one and the same circuit at some time in the past i.e a Ring final circuit....building alterations or cable faults could have resulted in open circuit on one or more of the ring conductor legs ,and the electrician could have decided to form two radials rather than repair the ring.

Still no problem with that but it is worth testing prior to the C.U change to check there is no continuity between any of their conductors. If your fitting a dual rcd board and you install the radials on different sides of the board then you would have the RCD tripping.

Just a bit of advice to ensure things go smoothly for you and the old Girl

 

[PC Electrics]

Nowt wrong with 20A/2.5 radials. I generally put them in for bedrooms and lounges (and sometimes small kitchens). Keep them at 20A in the new board though - why reduce the capacity to 16A, don't see what that is achieving really.

If they are on their own fuseways and it's the original board then thats a good indication they were installed like that. Nevertheless, check for signs they weren't once one ring circuit.

 

[rugbymacc]

and testing radials is so much simpler too

rings.... old fashioned is you ask me

radials..... are the future

 

[a1spark]

Hi PC how do you getaway with 20A radial in a kitchen or do you install more than one radial. ?

 

[ianmacd]

why reduce the capacity to 16A, don't see what that is achieving really.

You can see the entire cable run and know its not been derated by something?

 

[SidTheSparky]

Thanks for the replies. Greatly appreciated.

The fact that it was 2.5mm and not 4mm had me wondering, but my mind is now rested.

Checking it wasn't once a ring is a good point too, thanks

Binky, you sure you weren't in a hotel, lol.

 

[Voltimax]

As long as it doesnt exceed 50m2 and a ring is 100 and 4mm cable is 75m2 i believe. What if the radial is say nearer a 100m2 but your still under your zs is it still fine and carry on as you are?

What about your volt drop?

 

[Sidewinder]

Volti,

The std circuits in the osg take care of this for you.

 

[cadspark]

I don't install rings at all. 2 radials in a kitchen is also better than a ring. CU's have to be a bit big but at least you have more space to work with and testing time is reduced. How many sparks out there test or know how to test Ring finals correctly anyway. I've met a few who don't!

 

[Voltimax]

Volti,The std circuits in the osg take care of this for you.

*sigh* My point was that just because Zs is within doesn't mean to say the circuit is correct. When deviating from the circuits in the onsite guide you have to take other things such as volt drop into consideration.

OK a1sparks? (I assume your thanks to sidewinders post was a little bit of payback for our last encounter?)

 

[Andy™]

*sigh* My point was that just because Zs is within doesn't mean to say the circuit is correct. When deviating from the circuits in the onsite guide you have to take other things such as volt drop into consideration.OK a1sparks? (I assume your thanks to sidewinders post was a little bit of payback for our last encounter?)

OSG has max length of circuit, taking VD into account.