Home wiring a mess, help!

[securespark]

OK....done!

 

[John D v2.0]

rings are like marmite, half the people seem to love them, half hate them. Personally I like them, you can get a 32A circuit so easily cover your kitchen and utility room, all with only having to faff around with 2x2.5mm cable. You can fit 2x2.5mm t&e through one 20mm grommit with no trouble.
For upstairs/lounge circuits you can use the same cable on a 20A breaker.
With a 2.5mm radial in the kitchen/utility you'd need to think about 2 circuits, or running 4mm cable in and out of each socket (and a spur would be a pain without a 35mm back box)
That's my view, other opinions are available!

Regarding the running cables, if you're in england, and you know what you're doing, just cable it up as you say, either connect to the CU or don't depending what you feel comfortable, and then get the CU changed immediately afterwards. You can ask the electrician to do a full test of the accessories on the new circuit to make sure you got all the polarity correct etc.
It's all very well trying to talk to the electrician beforehand, but I can't imagine many want to have a big debate and splitting up the work, they'll want to come in, do the job get paid and leave, no messing around. If work is slow in your area maybe you'd have more luck.

 

[EFLImpudence]

With a 2.5mm radial in the kitchen/utility you'd need to think about 2 circuits, or running 4mm cable in and out of each socket (and a spur would be a pain without a 35mm back box)
That's my view, other opinions are available!

That's just not the case.

It's not an opinion. 4mm² is more flexible than 2.5 and much nicer to work.

Look how much huger it is:

 

[securespark]

Yeah. I like radials!
Rings are more involved to test and fault-find.

 

[ban-all-sheds]

Regarding the running cables, if you're in england, and you know what you're doing, just cable it up as you say, either connect to the CU or don't depending what you feel comfortable

He's not, but if he were then he would be creating new circuits, which would be notifiable.

and then get the CU changed immediately afterwards.

To what end?

It's all very well trying to talk to the electrician beforehand, but I can't imagine many want to have a big debate and splitting up the work, they'll want to come in, do the job get paid and leave, no messing around.

I'll correct that for you

It's all very well trying to talk to the electrician beforehand, but I can't imagine many want to have a big debate and splitting up the work, they'll want to come in, do the job get paid and leave, involvement in lying and cheating to get around the law.

 

[John D v2.0]

ban-all-sheds, new CU as the RCD in the current one doesn't work, and as it's an obsolete MEM board, the replacement RCD and adaptor to fit cost more than a new board.
F

To what end?

See above.

I'll correct that for you

Thanks, I knew I forget something from the sentence

 

[John D v2.0]

That's just not the case.

It's not an opinion. 4mm² is more flexible than 2.5 and much nicer to work.

Look how much huger it is:

View attachment 123113

Didn't realise it was more flexible, I thought it was a bigger size of the same material and as we know from joists, doubling the depth increases the stiffness by 8 times, so it's a bigger effect than just the small increase. Although even if it does hold, I only make it 31%stiffer and maybe two of them can squeeze through a 20mm grommet only just?.

But In all honesty I didn't actually try using 4mm, just 6mm for one circuit, so, I'll get a few metres of 4mm for next time I need an appropriate circuit and give it a go! Thanks

 

[rsgaz]

Didn't realise it was more flexible... ... ...I only make it 31%stiffer

With 4mm² cable, the line and neutral conductors are 7 stranded, rather than a single solid in 2.5, so it's more flexible.

 

[ban-all-sheds]

See above.

Yes, I know about the need for the CU.

What I meant was why do it that way?

Why not do the whole thing properly, as the one job which it really is?

An electrician wouldn't replace the cables, verify them, issue an EIC, and then immediately replace the CU, verify it, and issue an EIC for that, he'd do it as one job.

And that's the way this should be done, albeit with the OP doing some of the work with the agreement of, and under the supervision and direction of, the electrician.

 

[JohnW2]

With 4mm² cable, the line and neutral conductors are 7 stranded, rather than a single solid in 2.5, so it's more flexible.

Indeed - and, quite frankly, the external dimensions are so similar (particularly given that they vary a bit for both 2.5mm² and 4mm²) that I often struggle to tell which is which just by glancing.

Like JohnD (and, I suspect, many other DIYers), there was a time when I was hesitant to use 4mm² - since it sounded much bigger and stiffer. However, that was years ago, and when I did start using it, I discovered that it was at least as easy to work with as 2.5mm².

Kind Regards, John

 

[ban-all-sheds]

rings are like marmite

They aren't that bad.

 

[ban-all-sheds]

Like JohnD (and, I suspect, many other DIYers), there was a time when I was hesitant to use 4mm² - since it sounded much bigger and stiffer. However, that was years ago, and when I did start using it, I discovered that it was at least as easy to work with as 2.5mm².

And may well allow a 32A radial.

 

[JohnW2]

And may well allow a 32A radial.

Indeed. In fact, that just about the only situation in which I've used 4mm² cable.

I'm no particular fan of ring finals (although I do mention the CPC redundancy when the issue gets discussed) but, as you may recall, I regard 20A radials (just about enough for the theoretical load possible with just one double socket) as less-than-ideal in many locations, but I regard 4mm²/32A radials as 'fine'.

Kind Regards, John

 

[ban-all-sheds]

Plan B is to pick a CU where 25A breakers are available.

 

[John D v2.0]

interesting, well I've learned something useful so thanks all! although I'm still waiting for someone to tell me if I can squeeze two through a single 20mm grommit!