Interesting Conundrum 1.5 power

[SJD]

Are you quite sure these socket circuits are radials, and not 16A ring final circuits? (Yes yes, I know that would be rather non standard ...)

 

[Dustydazzler]

Are you quite sure these socket circuits are radials, and not 16A ring final circuits? (Yes yes, I know that would be rather non standard ...)

One cable at the board coming from each 16a mcb

unless they have ringed the socket all together ( which is possible )and then taken just one cable back to the board in a lolli-pop circuit

 

[UNG]

I suppose on the face of it you have to question the design criteria if the builder gave a brief directive of a working electrical installation with X number of sockets then it could be argued it meets the design brief whether it is compliant with the regs is a totally different matter, while any number of sockets can be wired on a 16A radial the size of the cable has to be considered, 1.5mm² may work but one consideration that may have been overlooked is volt drop and it can be very easy to lose 25m or more of cable on a radial and you start to creep over maximum allowed volt drop

You hear a lot about the east European's who move from site to site one week they are brickie's the next week on a different site they are joiners the next week they become ???? I think you get the idea

Faced with this job my only solution short of a rewire would be to install a whole new circuit for the extra sockets

 

[Pretty Mouth]

Carp design for sure, but I'd be surprised if this was dangerous, or even non compliant, all other things being correct.

Most recently built houses that I have worked on tend to have the cables for socket circuits run in the floor void between floors, dropping or rising to the sockets. There's not usually any need to run the cables through any significant insulation.

 

[UNG]

Carp design for sure, but I'd be surprised if this was dangerous, or even non compliant, all other things being correct.

Your clearly being very optimistic with that comment on compliance

Most recently built houses that I have worked on tend to have the cables for socket circuits run in the floor void between floors, dropping or rising to the sockets. There's not usually any need to run the cables through any significant insulation.

If there is any insulation does it really matter if it is significant or not for me you always calculate on the worst possible.
If a cable is running in a floor void is that in free air or is it a duct and given that you can also have heating pipework running in the same void how do you assess the thermal effects of that on the cable

 

[swaRRR]

Defiantly 1.5 cable , and all on 16amp circuits. Feels very much European

I didn't have time to add up all the sockets but I would suspect that there is around 6 or 7 sockets on each 16amp radial , possibly 1 circuit for upstairs , 1 for downstairs and 1 for the kitchen , but this would require further investigation

That's completely fine electrically speaking. It's literally what French regs specify. 8 sockets max on a 16a radial in 1.5mm.

Normally over there they have freezer, washing machine, dryer, and dishwasher on their own runs but kitchen countertop sockets used to be fine on 16a, i think they now have to be on 20a.

 

[littlespark]

That's completely fine electrically speaking. It's literally what French regs specify. 8 sockets max on a 16a radial in 1.5mm.

Normally over there they have freezer, washing machine, dryer, and dishwasher on their own runs but kitchen countertop sockets used to be fine on 16a, i think they now have to be on 20a.

But this house isn’t in France.

We have to work to BS7671, and have to design circuits with estimated load, installation method, current carrying capacity, length of circuit…..
If none of it mattered, it wouldn’t be there in the regs.

 

[UNG]

That's completely fine electrically speaking. It's literally what French regs specify. 8 sockets max on a 16a radial in 1.5mm.

Normally over there they have freezer, washing machine, dryer, and dishwasher on their own runs but kitchen countertop sockets used to be fine on 16a, i think they now have to be on 20a.

Connect all the wires up and it can be fine electrically speaking whether it is compliant in the UK is a different matter and that is the pertinent point of this thread

Clearly it isn't what the french regs say when you then qualify your comment in paragraph 2 with a load of separate circuits

 

[Pretty Mouth]

Your clearly being very optimistic with that comment on compliance

If there is any insulation does it really matter if it is significant or not for me you always calculate on the worst possible.
If a cable is running in a floor void is that in free air or is it a duct and given that you can also have heating pipework running in the same void how do you assess the thermal effects of that on the cable

The bulk of the insulation will be in external walls, under the ground floor slab, and in the loft/roof. With a couple of exceptions, there's no reason that cables for socket circuits would need to come into contact with these insulated spaces. One exception being bungalows where cables would be run in the loft and would indeed find themselves under a lot of insulation.

Otherwise, the worse that is likely to be encountered is insulation for sound proofing stud walls between some rooms, or in external walls of some timber frame housing. Method 102: In a stud wall with thermal insulation with cable touching the wall, giving us 16A for 1.5mm T+E.

In a building void is method B, so 16.5A. I take your point about the cables sharing a void with heating pipes, but this would apply to many circuits in centrally heated homes. I'll be honest, I don't give it a lot of thought.

I think VD is, as you mentioned earlier, where it may fail. We're probably starting at 240V rather than 230, so perhaps not a big deal real world, but still.

 

[swaRRR]

But this house isn’t in France.

We have to work to BS7671, and have to design circuits with estimated load, installation method, current carrying capacity, length of circuit…..
If none of it mattered, it wouldn’t be there in the regs.

Where in BS7671 does it say you can't use 1.5mm cable with 16a breakers?

Anyway my point was it's electrically sound and if it doesn't break a reg then it shouldn't be coded anything surely?