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.

 

[littlespark]

is that 10 x doubles?

realistically, they're not all going to be used at the same time? or is it something like a school workshop where several people will be working.

There must be a reason they give a floor area, rather than a number of points.... but it'll be down to the installer to know how many points for that area is being silly about it.

 

[timhoward]

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?

I think the only reference to 50 sq. m is in informative appendix 15 where it says "historically the floor area served has been limited to 50 sq m". So not a hard and fast rule and somewhat half-heartedly stated even there.
Total load is the main thing.
1 nail gun and a heater could make things interesting on a B16.
Are you at all tempted to do it in 4mm csa, just to leave it more flexible with loading?

 

[westward10]

There is no restriction to the number of outlets you can put 500 on it if you wish.

 

[Brian246]

It’s all just about suitability, if you think the demand won’t exceed 20amps then it’ll be fine, if not I’d probably split the circuit to two radials or upgrade to a 4mm. My personal take on the 50m2 rule is the cable length and potential volt drop? Correct me if I’m wrong though!

 

[brianmoooore]

IIRC. historically the max. area for 2.5mm2 T&E/20A MCB was 20m2. 4.0mm2 T&E/32A MCB was 50m2, and 2.5mm2 T&E ring was 100m2.

 

[loz2754]

Reading regulation 433.1 i know it states 50m²

Not in my book.

 

[Stephen-d]

is that 10 x doubles?

realistically, they're not all going to be used at the same time? or is it something like a school workshop where several people will be working.

There must be a reason they give a floor area, rather than a number of points.... but it'll be down to the installer to know how many points for that area is being silly about it.

Yes doubles. No they won't be used all at the same time, i gather its just for ease of moving around and not using extension leads

 

[Stephen-d]

I think the only reference to 50 sq. m is in informative appendix 15 where it says "historically the floor area served has been limited to 50 sq m". So not a hard and fast rule and somewhat half-heartedly stated even there.
Total load is the main thing.
1 nail gun and a heater could make things interesting on a B16.
Are you at all tempted to do it in 4mm csa, just to leave it more flexible with loading?

Yes 4mm did also cross my mind and possibly the better option i guess

 

[Stephen-d]

IIRC. historically the max. area for 2.5mm2 T&E/20A MCB was 20m2. 4.0mm2 T&E/32A MCB was 50m2, and 2.5mm2 T&E ring was 100m2.

Sorry have i got this wrong? Im looking at appendix 15, is this the right place to look?

 

[Stephen-d]

Not in my book.

Sorry have i got this wrong? i am looking at appendix 15, is this the right place to look?

 

[brianmoooore]

I was referring to Edition 15, not appendix 15.

 

[Stephen-d]

I was referring to Edition 15, not appendix 15.

Ah apologies, I was looking at the 18th edition

 

[pc1966]

As above, you can put as many sockets on as you want. The fact you can does not mean you should!

Really it comes down to expected use/load. If most are phone chargers, etc, then 10 doubles sockets are no big deal, but if a large area than a RFC makes more sense, or going in 4mm radial, so 32A MCB is reasonable.

 

[Stephen-d]

As above, you can put as many sockets on as you want. The fact you can does not mean you should!

Really it comes down to expected use/load. If most are phone chargers, etc, then 10 doubles sockets are no big deal, but if a large area than a RFC makes more sense, or going in 4mm radial, so 32A MCB is reasonable.

Yea I understand that, since posting this and seeing the feedback I am favouring the 4mm radial, it is not a large area that it will be covering, I have been told there won't be any heavy loads its just the ease of having sockets in different locations. Thanks for your help ?

 

[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!!