does this comply?

[Andy™]

I will not disagree with you at all but according to the brb its not complaint.

and another view to show it complies

the whole point of the wiring regs is to make sure the wiring is safe.

now in both examples (on their own or sharing with a ring), there is no difference, except the lack of ring main. the safety of the radial/spurs has not changed. so since no change in level of safety, you can easily argue that it still complies

 

[ianmacd]

No you can't. You can argue its still as safe but they are not the same thing.

 

[green-hornet]

Are we now to assume that a 2.5mm radial is safe if placed on a 32amp MCb?

After all, any appliance plugged into it will have at least a 13 amp fuse.

 

[Riggy]

Are we now to assume that a 2.5mm radial is safe if placed on a 32amp MCb?After all, any appliance plugged into it will have at least a 13 amp fuse.

Almost!

We can make that assumption IF (as in the original post) each cable feeds only one point.

 

[green-hornet]

Ok, lets say that we have a spare 32 amp type b, and we now run two meters of 2.5mm twin and earth down to a fused spur for the boiler, rated fuse 3 amp.

Now we have 1 socket required next to the boiler for the kettle and toaster, so lets run that from the same 32amp MCB.

Two years later, we need another couple of sockets, I know lets run them from that socket next to the toaster.

Whilst we are at it, because we are going to fuse everything at the plug, lets just run a 2.5mm from the 45amp shower circuit to the bedroom for the wifes curlers.

Do you see how ridiculous this is going?

As all appliances are fused I am going to start wiring from the 100amp main switch, after all ,by all accounts it will still conform??

Now I am getting silly.

 

[ianmacd]

No more silly than the argument it complies because of the fuse in the plug.

 

[Lee321]

seen the poll recently ian?

:^O

 

[ianmacd]

the pointless poll? Its immaterial anyway as its not open for voting. It doesn't comply simple as. IEC agree.

 

[green-hornet]

I have just done multiple cable calculations down to 5 amp, protected by a 32 amp type b, and always get 4mm, am I doing something wrong?

 

[Lee321]

please show your workings :Salute

however you dont have to do calcs for standard circuits

 

[ianmacd]

Standard circuits don't protect a 2.5mm radial with a 32A mcb.

 

[Andy™]

a ring main is a standard circuit, and can have 2.5 feeding a socket.

 

[ianmacd]

Again, this discussion surrounds a radial NOT a ring.

 

[Andy™]

which is irrelevant. the same 2.5 with socket has the same protection if its attached as a spur to a ring, or its own radial.

the spur to the ring could easily be taken from the MCB instead of an accessory, so you cannot argue that it complies if its added to a MCB with a ring connected, yet it cannot comply if its connected to an identical MCB that doesnt have a ring attached

 

[ianmacd]

Whatever. Its not complaint. Thats the bottom line. IEC even say so. Maybe you should drop it now.

 

[Badger]

i have an idea, why dont we just dump allowing spurs from ring mains, as they shouldnt be allowed in my opinion, if i can install on the ring correctly then i always do do

:Salute :Salute:run

 

[ianmacd]

I think we should dump rings all together.

 

[Andy™]

I think we should dump rings all together.

have to agree with you on that one

 

[green-hornet]

I have recently started to do more radials than rings, makes more sense really and easier to comply.

 

[Badger]

[quote name='Andy