Extending a ring mains

Owain_Moneysaver

rich13348 wrote: »

While we are on the subject I was looking at my CU and the main switch is rated 100A but the total potential load over all circuits is 172A. Its unlikely that I will reach that but let's say for instance I had my oven on full whack extractor fan on wife taking a rediculously hot shower as well as boiling the kettle and toasting all my crumpets in the toaster with eggs in the micro and TV and radio on full blast not to mention all the lights on.

Could this potentially trip the main switch without tripping each individual MCB?

Probably not (apart from teh fact that main switches don't trip anyway).

Oven - even if on it's usually only about 3 kW maximum, and it will cycle on its thermostat once it's up to temperature.

Shower - if electric, then probably 10 kW max, and probably for a short period only unless Mrs Rich spends half an hour in there

Kettle - 2 - 3 kW but only for a few minutes.

TV and radio - negligible

Lights - unless you have halogen downlighters, negligible.

PheoUK

If he has used 1.5mm he's ripped you off. Ring main should be 2.5mm T&E minimum,

Are you SURE he's used 1.5mm? It's not that easy to tell visually from a quick glance (it's taken me a little bit to make sure I've got the right cable looking in a big bag of the stuff before.

If you are certain that he's used 1.5mm, then get another electrician into check it very rapidly.

onomatopoeia99

rich13348 wrote: »

Well in line with part P it would all have to be signed off by a qualified electrician which I'm sure the OP was going to do anyway

Extending a ring is notifiable work? It used to be, but I thought the most recent edition of the regs relaxed it to only new circuits being notifiable.

Obviously part P is a good thing to use to scare people coming onto forums with questions about doing electrical work in their own homes, whether or not the work is notifiable, as most people won't want to plough through the relevant primary legislation and statutory instruments that have updated it..

zax47

PheoUK wrote: »

If he has used 1.5mm he's ripped you off. Ring main should be 2.5mm T&E minimum,

Are you SURE he's used 1.5mm? It's not that easy to tell visually from a quick glance (it's taken me a little bit to make sure I've got the right cable looking in a big bag of the stuff before.

If you are certain that he's used 1.5mm, then get another electrician into check it very rapidly.

Read the whole thread! Cable was wrongly identified by the OP because 2.5 T&E has a 1.5 CPC "Earth". It is wired in 2.5....