13a sockets on radial with 20a dp switch

[snapshot25]

buildings regulations are the law, you are legally obliged to apply for building consent before carrying out any works, and you're legally obliged to have it tested. If the person testing deems anything incorrect, then you are obliged to make changes.

Make your mind up.

building regulations are strictly guidelines (not a legal requirement as people assume,

However, approved documents are still only guidance and not statutory requirements,

Who said anything about Approved Documents.

people generalise and assume that deviating from the approved documents automatically means ignoring building regulations. e.g. put simple, the building regulation would say something like "provisions to be made for disabled access" it is up to the client to decide what is deemed necessary to comply with that, and the approved documents are there to give you an automatic list of ways that you can comply, but building control doesn't expect all the guidelines to be followed, as many are impractical especially when making alterations in older buildings. Same applies to electrical work. And what I'm saying is, most houses do not comply with recent building regulations, and are not required to, because they have been that way a number of years without problem. It is up to the owners to decided whether or not they want to spend the money to meet modern compliance or not (which would involve getting building control to carry out an inspection).

 

[flameport]

The thing is, you can't install a 13a socket on a 6 or 10a mcb

Why not? Which regulation prohibits this?

you may be able to use 1.5mm cable if the distance is suitable

In a typical house, circuit length is usually of no relevance at all. And no reason why you couldn't have a 13A socket on a 10A circuit breaker, all wired in 1.0mm cable.

The US system makes sense in this way, as you'll find a lot of bedrooms don't have ceiling lights, but the light switch operates one side of one or more regular two-gang outlets around the room. All circuits are individual 15a lines

Except for the 10A circuits. And the 20A ones. And all the other ratings which are available.

and all flex is rated at 15amps (as plugs are unfused).

Except for the flex rated at 10A. And all the other sizes of flex which are available.

In the UAE, they do put uk-style 13a sockets on 6a breakers using thinner cables for TV and lamp locations as the plugs themselves don't have fuses, and people staying in hotels frequently blow fuses plugging the iron or hairdryer into the tv socket lol.

Total fail. And I don't mean the people in the UAE.

 

[snapshot25]

The thing is, you can't install a 13a socket on a 6 or 10a mcb

Why not? Which regulation prohibits this?

you may be able to use 1.5mm cable if the distance is suitable

In a typical house, circuit length is usually of no relevance at all. And no reason why you couldn't have a 13A socket on a 10A circuit breaker, all wired in 1.0mm cable.

The US system makes sense in this way, as you'll find a lot of bedrooms don't have ceiling lights, but the light switch operates one side of one or more regular two-gang outlets around the room. All circuits are individual 15a lines

Except for the 10A circuits. And the 20A ones. And all the other ratings which are available.

and all flex is rated at 15amps (as plugs are unfused).

Except for the flex rated at 10A. And all the other sizes of flex which are available.

In the UAE, they do put uk-style 13a sockets on 6a breakers using thinner cables for TV and lamp locations as the plugs themselves don't have fuses, and people staying in hotels frequently blow fuses plugging the iron or hairdryer into the tv socket lol.

Total fail. And I don't mean the people in the UAE.

There isn't a regulation that you can't do that, there probably is guidance that you can't, but it's common sense. You shouldn't install something that could potentially draw more current than it is designed for. That's what 2a and 5a sockets were designed for. And the majority of US radials are on 15a breakers. 20a is usually designed for outlets under windows which are used for air conditioners which are fitted with suitable flex. If a fault occurs on an appliance with <15a flex plugged into a 20a circuit, overcurrent protection kicks in, however, the problem in the US is that people use 15a extension cords to plug in higher current appliances, which causes the cable to melt, and hence a fire.

 

[EFLImpudence]

Why can't these 'lamp sockets' be wired so that they comply?

I.e. on a proper radial final or spurred from the ring final (through FCUs if necessary) via a 20A switch (wherever you want) so that it wouldn't matter if someone plugs in a vacuum or even a heater - no different from the washing machine socket in the kitchen.

 

[SimonH2]

Why not? Which regulation prohibits this?

You shouldn't install something that could potentially draw more current than it is designed for.

Sorry, but I fail to see the problem - you label the socket as being for lights only, the circuit cannot be overloaded as the breaker will trip if the user tries.

The alternative is to use "funny" sockets, the user is p***ed off at having to change plugs if he moves lights around, and the risk is increased that some muppet will incorrectly wire a plug.

Don't forget that almost all houses wired in the last several decades have circuits that can very easily be overloaded to the point that the fuse blows or breaker trips - currently called a ring final circuit, aka ring main. Plug in a few heaters (about 7 1/2kW worth or more) and you've overloaded it.
Said heaters could well include dishwasher, tumble drier and washing machine.

 

[snapshot25]

[/quote]Sorry, but I fail to see the problem - you label the socket as being for lights only, the circuit cannot be overloaded as the breaker will trip if the user tries.[/quote]

that's just bad practice, not right really. What I want to know, is why electricians don't use 20a dp switches on 15a or 20a radials to operate some normal 13a sockets in a room. Is it just because they haven't thought of it?

I agree that rings should be done away with, because they are dangerous. And it is very easy for spurs to be overloaded, because you effectively have one spurred 2.5mm cable on a 32a mcb, and people regularly plug in more than 20amps into spurred double sockets.
If all circuits were radials, it would be very economical to have switched lines from the lightswitch this way, without the nuisance of round pin sockets.

 

[RF Lighting]

Utter utter garbage.

Rings are not dangerous.

Spurs can not be overloaded.

Radial circuits can be overloaded just as easily if you could actually understand what simonH2 was trying to tell you.

 

[EFLImpudence]

What I want to know, is why electricians don't use 20a dp switches on 15a or 20a radials to operate some normal 13a sockets in a room. Is it just because they haven't thought of it?

It would be if they hadn't thought of it.

See above and kitchens

I agree that rings should be done away with, because they are dangerous. And it is very easy for spurs to be overloaded,

Not if regulations are followed.

because you effectively have one spurred 2.5mm cable on a 32a mcb, and people regularly plug in more than 20amps into spurred double sockets.

2.5mm² has a CCC of 27A, method C.
It's the sockets which are doubtful.

 

[riveralt]

What I want to know, is why electricians don't use 20a dp switches on 15a or 20a radials to operate some normal 13a sockets in a room.

Why do I need to put a switch in the way of 13amp sockets?

I agree that rings should be done away with, because they are dangerous.

They only become dangerous when they are badly installed and maintained.

And it is very easy for spurs to be overloaded, because you effectively have one spurred 2.5mm cable on a 32a mcb, and people regularly plug in more than 20amps into spurred double sockets.

Methinks you have been sniffing the old aerosol can, 20Amps is well within the rating of 2.5mm T&E cable.

If all circuits were radials, it would be very economical to have switched lines from the lightswitch this way, without the nuisance of round pin sockets.

You do seem to have a paranoia about having plate switch activated sockets in your (everyone elses) home - maybe its amateur architect in you coming out.
The reality is that from my experience of designing domestic circuits very very very few people want what you want.
In fact some would probably argue that your ideas are a backward step in designer lighting when there are many, better, ways of providing general, task and mood lighting. The lamp on a pole is so last century.

 

[snapshot25]

Utter utter garbage.

Rings are not dangerous.

Spurs can not be overloaded.

Radial circuits can be overloaded just as easily if you could actually understand what simonH2 was trying to tell you.

radial circuits can't be overloaded, because the cable carrying capacity exceeds or equals to the mcb rating. On ring circuits, spurs are not required to be spurred with a 13a fcu, so it's possible to plug a dishwasher and a tumble dryer into the same double socket, drawing 26 amps on a 2.5mm spur on a 32a mcb. The cable will overheat, as 2.5mm t£e is rated at 21amps and the socket will get hot, melting the plastic safety guards on the base of the prongs, creating that charred effect on the surround of the socket shutter (or fire). This is very common.

 

[RF Lighting]

Wrong again.

Becoming a bit of a bad habit of yours isn't it.

 

[EFLImpudence]

, as 2.5mm t£e is rated at 21amps

No it isn't.

See above, again.

 

[riveralt]

The cable will overheat, as 2.5mm t£e is rated at 21amps and the socket will get hot, melting the plastic safety guards on the base of the prongs, creating that charred effect on the surround of the socket shutter (or fire). This is very common.

You really have been at the old aerosal can haven't you.
2.5mm2 T&E has a BS7671 rating of 27Amps and even that has a significant safety margin built into it.

 

[snapshot25]

Methinks you have been sniffing the old aerosol can, 20Amps is well within the rating of 2.5mm T&E cable.

in a kitchen, a tumble dryer and a dishwasher on one double 13a socket will overload the 2.5mm spur cable from the 30a ring, because the 30a mcb will not blow at 26 amps. No question. Same thing with portable space heaters plugged into the same wall socket as other heavy current appliances.
In my experience, many people rarely use the main light in a bedroom or living room, and prefer low-level lighting (table lamps, standard lamps, accent spotlights, e.t.c.) have you ever seen how popular the lighting section is in Ikea?