Why are some of my sockets on a 16 Amp circuit breaker?

[Martyn Bell]

I had a garage conversion done a few years ago and I have now noticed that the sockets on this circuit appear to be covered by a 16 Amp circuit breaker.
Is this a radial circuit and if so, is there a limit to how many sockets can be connected to it?

 

[jurassic sparkk]

As much sockets as you like however, load is limited to16a

 

[SUNRAY]

I had a garage conversion done a few years ago and I have now noticed that the sockets on this circuit appear to be covered by a 16 Amp circuit breaker.
Is this a radial circuit and if so, is there a limit to how many sockets can be connected to it?

It is likely to be on a radial and there is no limit. However bear in mind the limit will be 16A so no running welder & tumble drier & electric heaters all at the same time.

 

[Martyn Bell]

Thanks for your help. I guess the light circuit was changed over to the R.C.D to comply with regulations?

 

[plugwash]

is there a limit to how many sockets can be connected to it?

British standards (unlike some countries) for electrical installations do not place any explicit limits on how many sockets should be on a circuit.

That said, overload protection is not supposed to be used for load-limiting. You are not supposed to design circuits that you anticipate will be overloaded. Personally I'd say more than one room on a 16A breaker is pushing it.

 

[Murdochcat]

As many as you want BUT consider your usage.

20A radials are much more common these days for areas other than kitchens ands utilities

 

[SUNRAY]

When I did some work at my daughters house I found the ring covering the whole 3 bed house apart from the kitchen but including conservatory with 1.5KW panel heater and aircon in lounge was on the 6A MCB labelled 'upstairs lights' and all lights were on 32A MCB labelled 'ring'. They had been there best part of 4 years with no tripping other than rcd when doing something outdoors.

 

[ericmark]

I can't remember what amendment was in force in 2014 when it seems installed, 17th needed bathroom lights RCD protected, that came in 2008, regulations are not retrospective, in fact unless rented not law, but the problem arises when new items are installed, the person signing the minor works or installation certificate has to sign that it meets the appropriate regulation, as he reads the rules, and we don't all agree as to what is required.

However an EICR is not tied to regulations, we have two types of fail, dangerous and potentially dangerous so if not potentially dangerous in 2014 seems unlikely anyone would consider it potentially dangerous today.

I know I have 4 sockets and a FCU limited to 3 kW in all, it is because supplied from the solar panel inverter, and is the limit to what the battery can supply, so we do get odd circuits, last house had some sockets on a 16A MCB as originally was for the immersion heater. At work I had a radial at 20 amp because some daft twit had extended it with 2.5 mm² instead of the 4 mm² it was originally wired in.

So to add more sockets, in theroy they should be protected with a type A RCD, and your RCD is a type AC, personally I would not be worried, but if one was pedantic it would need changing, in fact could say need metal consumer unit and all RCBO's, but I am sure most would not really be worried about the older type AC RCD most are just thankful any RCD.

 

[SUNRAY]

So to add more sockets, in theroy they should be protected with a type A RCD, and your RCD is a type AC, personally I would not be worried, but if one was pedantic it would need changing, in fact could say need metal consumer unit and all RCBO's, but I am sure most would not really be worried about the older type AC RCD most are just thankful any RCD.

I thought metal CU and fixings for cables only related to exit routes.

 

[ericmark]

I thought metal CU and fixings for cables only related to exit routes.

Maybe they do, but today can't it seem buy a plastic one even if you wanted. However seen on these pages where code C2 has been given for items I would regard as safe.

 

[Ragnar_AT]

Depending on where you‘re located, design guidelines seem to assume an average load of 200 or 300 W per general purpose domestic socket (doubles count as one socket). So with no more than 12 double sockets you‘re perfectly fine (assuming the highest number I‘ve encountered so far). So I‘d question the assumption of „no more than one room“. Obviously kitchens are a different beast.

 

[plugwash]

Depending on where you‘re located, design guidelines seem to assume an average load of 200 or 300 W per general purpose domestic socket (doubles count as one socket). So with no more than 12 double sockets you‘re perfectly fine (assuming the highest number I‘ve encountered so far). So I‘d question the assumption of „no more than one room“. Obviously kitchens are a different beast.

AIUI the thinking in the UK has been that using "number of sockets" to estimate load is counter-productive. That is people will use about the same amount of power in total regardless of whether they can plug everything directly into the wall or they have to use a bunch of extension leads. Since we mostly use 32A circuits in the UK we aren't used to thinking about what we plug in and where.

There are max floor area guidelines for 32A (which for some reason are different for rings and radials) and 20A socket circuits, but I don't think there are any for 16A ones. A couple of portable heaters could easily be enough to overload a 16A circuit, less likely on a 20A and much less likely on a 32A, hence why I would consider it poor design to use a 16A circuit to feed more than one room.

 

[Ragnar_AT]

How likely is it that your central heating breaks and you still want to heat every room? Inmy experience that’s a rare occasion (thankfully) and most people are content using portable heaters in one or two rooms, most of which won‘t be on at the same time, so it’s not much of an issue in my book.

The only time I‘ve ever managed to trip a circuit with portable heaters was in a holiday home with poor central heating that took 24 hours to get the rooms up to temperature.