DIY a new ring main

[pete01]

I was planning to leave all the channels and boxes open, conduit in place

You could try but why would anyone bother....best to get someone on board first.

Others may disagree.

 

[pete01]

Or do it all yourself and get an EICR done afterwards....but I didn't say that.

 

[AJoe]

Apart from connecting to the consumer unit I'm fairly confident I could do it all myself, but I wouldn't then expect an electrician to come in and stamp their name on something they can't see.

 

[flameport]

installing a new ground floor ring main in a block built house.

Is a ring an appropriate and considered choice for this installation?

 

[AJoe]

Is a ring an appropriate and considered choice for this installation?

Ground floor, 2 rooms plus hallways. Nothing kitchen related.

9-10 double sockets in total, nothing high draw.

I'm actually guessing that it's a ring main right now, but as far as I know the work I would do would be more or less the same either way. I would take advice from the electrician on this before I started.

 

[AndyPRK]

Is a ring an appropriate and considered choice for this

It’s only an extra cable back to the CU.
So if that is a short run, why not.

A radial could allow op to spider out from various sockets if that layout made more sense. (Max of 3 cables per socket for ease)

Or maybe 2 radials would suit the layout?

 

[AJoe]

 

[AJoe]

Red dots are proposed sockets. Red box is consumer unit under stairs. All floors are concrete, all walls are blockwork.

 

[AndyPRK]

That layout does seam to suit a ring ok

But even I would struggle to justify a ring for one living room.

Running it off a radial with 20A mcb will be fine.

What is the tv socket mounted on ?

 

[AJoe]

That layout does seam to suit a ring ok

But even I would struggle to justify a ring for one living room.

Running it off a radial with 20A mcb will be fine.

What is the tv socket mounted on ?

I would be happy to be guided by the electrician on whataver way they feel is best. Really the point for me is to do the 'grunt' work of physically routing through the concrete and block work.

The TV point (well observed) is on a brick (deactivated) chimney breast.

 

[ericmark]

OK 10 drops, so around 5 foot each so 100 foot, then add the around the room distance another 50 foot, and also the 1/3 rule for drilling beams may add to that, so looking at around the 200 foot, or around the 60 to 70 meters of cable.

With a ring final with 32 amp MCB allowed 106 meters so that's OK, with 20 amp radial in 2.5 mm² 32 meters, so single radial is out, even with 16 amp, 42 meters still not good enough, so would need to use 4 mm² so then at 20 amp 56 meters so still not really going to work so 16 amp with 4 mm² 72 meters so just about.

So yes only sensible option is a ring final. This is the design stage, and you still need to sign for the design if you have done the design.

 

[EFLImpudence]

OK 10 drops,

Why? Horizontal chases except past doors?

 

[AJoe]

OK 10 drops, so around 5 foot each so 100 foot, then add the around the room distance another 50 foot, and also the 1/3 rule for drilling beams may add to that, so looking at around the 200 foot, or around the 60 to 70 meters of cable.

With a ring final with 32 amp MCB allowed 106 meters so that's OK, with 20 amp radial in 2.5 mm² 32 meters, so single radial is out, even with 16 amp, 42 meters still not good enough, so would need to use 4 mm² so then at 20 amp 56 meters so still not really going to work so 16 amp with 4 mm² 72 meters so just about.

So yes only sensible option is a ring final. This is the design stage, and you still need to sign for the design if you have done the design.

Really appreciate this info again.

Meeting with an electrician on Monday who I've knows as a multi trade guy for a few years, so hopefully we can scribble something out that works.

 

[ericmark]

Why? Horizontal chases except past doors?

Or corners, so 6 drops instead of 10, but have not included the cable used to comply with the 1/3 rules for drilling beams, however at ceiling height there is a safe zone, so there are ways around the 1/3 rule.

Many years ago my son was an apprentice for an electrical firm and he was given the task to wire up new builds, these had composite beams, with holes in, so he did not need to run cable towards the centre of the room to cross the beams, then the builder changed to wood beams, he was told about the 1/3 rule, so he drilled the beams in the correct place, but this causes him to use more cable. And he was wiring upper and lower split. This resulted in him using too much cable.

The cure was side to side split, better idea anyway, ring finals then have a more even load.

Horizontal chases around corners are not permitted, I will admit I see no good reason why not, but we all know where cables must run now, so I know I hit a horizontal cable going around corners as I had not even considered anyone would have put the cable there.

 

[EFLImpudence]

Horizontal chases around corners are not permitted,

Of course they are if there is an accessory on both sides.

OP just needs one or two sockets on the bottom wall in the sitting room.