Sockets on a radial circuit

[Stephen-d]

Hi all,

After some advice here to settle my mind, is there any regulations to limit the number of sockets on a 20A 2.5mm radial? Reading regulation 433.1 i know it states 50m² floor area, but i can't seem to find anything about the number of sockets? Or is it just the total load that determines this?

The reason is, i have been asked to install some sockets, 10 in total, for means of flexibility of plugging appliances in around the area, I'm being told that the sockets will be used for power tools, chargers, a computer and occasionally a heater.


Any information to help clear this up is appreciated.

 

[pirate]

If you DID put 500 sockets in, you'd save on cable length...but your wrist would ache from making all the terminations...
and it would be rather more costly

 

[Mike Johnson]

For information only, the French Regulations allow twelve sockets on a 20amp MCB 2.5mm radial and eight on a 16amp MCB 1.5mm radial, a recent amendment to the regs was that a double socket counts as two, so prior to this you could have twenty four outlets on a 20amp 2.5mm.

 

[brianmoooore]

For information only, the French Regulations allow twelve sockets on a 20amp MCB 2.5mm radial

UK 20m2 (4m x 5m room). A room that size would have around 6 doubles, so not a great deal different.
I assume that if it's known that the sockets are going to be heavily loaded, then design considerations would override the general rule, just as in the UK.

 

[Mike Johnson]

Except for the amendment a couple of years ago where you could instal twelve doubles, forgot to mention the regs only allow for six sockets in a Kitchen above the worktop in 2.5mm, and appliance's have to be on their own 2.5mm 20amp radial.

 

[Rockingit]

The answer, I think, is more a practical one than theoretical - at some point you'll run out of allowable Zs!!

 

[pc1966]

The answer, I think, is more a practical one than theoretical - at some point you'll run out of allowable Zs!!

From the OSG 4mm on 32A B is limited to 43m on VD (really 86m if loads are evenly distributed, as they probably would be with multiple sockets over a couple of rooms) and potentially much less on Zs (if, like me, you really don't like the idea of depending on the RCD for disconnection). Then it has 28m on TN-S typical max Ze

For comparison a RFC with 2.5mm on 32A B is 106m / 96m

For the OP's original 2.5mm & 20A probably around 84m on VD (distributed load) and 60-70m or so on Zs?

 

[Rockingit]

The true answer is provided in the Design Guide....

 

[Stephen-d]

Thanks for the information and help, the sockets won't be heavily loaded and not all used at the same time but just to be safe I think i am going to go with the 4mm radial ?

 

[Dartlec]

If you DID put 500 sockets in, you'd save on cable length...but your wrist would ache from making all the terminations...
and it would be rather more costly

Just been doing a loft extension with a client who really likes sockets.... A child's fairly normal size bedroom with 12 sockets - I think he wanted them near the bed, but couldn't decide where the bed was going!

Also 4 round pin sockets on the light circuit in the master bedroom, while will probably never get used....

I did put in 2 x 20A radials for 4 upstairs bedrooms when I might well have only gone with one in a 'normal' installation.

 

[brianmoooore]

If I could go back 40 years to when I wired my own house, each kid's bedroom would have been a separate 2.5mm2 radial. individual control over each room from the CU.

 

[nicebutdim]

Other than slightly increased initial costs, I can see only benefits to running several circuits where tradition might dictate that one would suffice.

Less inconvenience in the event of a fault. Less time involved in fault finding, should future issues arise. Reduced likelihood of a broken neck when extension leads are used in place of diagnosis and repair...

 

[Dartlec]

Other than slightly increased initial costs, I can see only benefits to running several circuits where tradition might dictate that one would suffice.

Less inconvenience in the event of a fault. Less time involved in fault finding, should future issues arise. Reduced likelihood of a broken neck when extension leads are used in place of diagnosis and repair...

If AFDDs are required in AMD2 then I can see new builds going back to as few circuits as possible!

 

[nicebutdim]

If AFDDs are required in AMD2 then I can see new builds going back to as few circuits as possible!

This is true, although their cost is likely to fall quite rapidly in such an eventuality.

 

[mydigitalhome]

Another consideration should be what’s the expected earth leakage on that circuit.