Spur from a spur. Regulations, problems and solutions - discuss.

[steptoe]

this is the kind of situation you need to have the balls and confidence to fill in the deviations box for.

fill in the box with your reasons and how you have ensured it is still safe and all is good in the world tonight.

 

[Graham Lister]

Dave, how does this soundo what I suggested earlier and swap your double socket outlet for a 13A FCU and a single socket.

This then gives you - ring to FCU to SSO (13 A)

Then....

Spur off the supply side of the FCU and run this cable to a second 13 A FCU which then feeds your second socket outlet.

Both sockets are then rated 13 A for each appliance.

Both sockets are limited to 13A by the individual FCUs.

The cable is limited to 26A by the FCUs - even if someone spurs off the socket outlets at a later date.

Happy days

Dont like the logic with this, you say people should be able to change a single to a double socket. Why cant they change FCUs to double sockets? following this logic we should then be prepared for them to change their light switches to double sockets. This now dictates that 4mm is the minimum size cable of choice for all domestic lighting/socket circuits. When the regs say a single socket I dont think it has anything to do with the fact that it may be changed for a double later on.

In this situation the 2 single sockets would have been better than the extension lead. I mean what if in future someone bypasses the fuse on the bit of 1.5mm extension lead cable and plugs in four 3kw heaters. Before you say that they could do that on the 2.5mm spur on spur, they could but the 2.5mm would give a couple more days use before melting and kaboom bad day explode

 

[ADS]

Dont like the logic with this, you say people should be able to change a single to a double socket. Why cant they change FCUs to double sockets? following this logic we should then be prepared for them to change their light switches to double sockets. This now dictates that 4mm is the minimum size cable of choice for all domestic lighting/socket circuits. When the regs say a single socket I dont think it has anything to do with the fact that it may be changed for a double later on.In this situation the 2 single sockets would have been better than the extension lead. I mean what if in future someone bypasses the fuse on the bit of 1.5mm extension lead cable and plugs in four 3kw heaters. Before you say that they could do that on the 2.5mm spur on spur, they could but the 2.5mm would give a couple more days use before melting and kaboom bad day explode

You are now talking about the ridiculous.

We can't allow for people doing dangerous things in the future - that's down to them.

I was talking about the very common practise of swapping out a single socket for a double - you don't even have to change the back box with these:

http://www.wickes.co.uk/Converter-Kits-Single-To-Double/invt/710075?awc=1563_1282898426_d55a9bee92fb118daddc777efc0c4234

 

[ADS]

When the regs say a single socket I dont think it has anything to do with the fact that it may be changed for a double later on.

With this you are correct.

What they are trying to tell you is that an unfused spur can only supply one 'point'....

One single socket outlet

One double socket outlet

One item of fixed equipment

One POINT

Not TWO single socket outlets, because thats two points.

 

[m4tty]

Dont like the logic with this, you say people should be able to change a single to a double socket. Why cant they change FCUs to double sockets? following this logic we should then be prepared for them to change their light switches to double sockets. This now dictates that 4mm is the minimum size cable of choice for all domestic lighting/socket circuits. When the regs say a single socket I dont think it has anything to do with the fact that it may be changed for a double later on.In this situation the 2 single sockets would have been better than the extension lead. I mean what if in future someone bypasses the fuse on the bit of 1.5mm extension lead cable and plugs in four 3kw heaters. Before you say that they could do that on the 2.5mm spur on spur, they could but the 2.5mm would give a couple more days use before melting and kaboom bad day explode

I would have thought if what the spark does complies, then who cares what other people do afterwards. It's their problem if their messing with something they know nothing about.

 

[Lee321]

i think your spot on there chris.

433.1 is saying we should design our cable so that its unlikely to carry overload. i think we all agree 2 points served will not put that 2.5mm in harms way.

and 433.1.5 says we meet 433.1.1 if the cable when under intended use is unlikely to be exceeded for long periods (should the current be overload)

even app15 says it does NOT cover other aspects (methods) of protection against overload. i.e its not the only way a ring with spurs can be designed.

 

[Badger]

could you not replace that cable to the original socket with a 4mm t+e ? then to another single in 4mm ?

 

[ianmacd]

Would still be a spur form a spur on a ring. My belief in why this is not allowed despite, as some have pointed out, being as safe as a dso, is that it would set a president that could be misunderstood. This is why the limit of one accessory per spur point on a ring is there.

Rings should be scrapped as there is no way to ensure they are safe unlike a radial. Have found too many either broken ring continuity or where a 'spark' has hung an unfused radial off of a JB found under a floorboard to multiple sockets.

 

[Badger]

rings are far safer than radials from a earthing poing of view, because with radials if you have a loose earth between point 3 and 4 point 4 will loose its earth, but with a ring unless you have 2 loose earths at the fuse board, then your earth will still be at each socket albeit one side from each point, ie 2 radial earths instead of a ring earth, the best way this could be made the safest is to make 25 amp mcbs a normal breaker size, where by it replaces the 32 amp used on ring mains, or wire it in 4mm simples

 

[ianmacd]

or wire it in 4mm simples

Wire what?