Hi every one. Thanks for letting me. Can I take my foot out of the door now?

[biggles74]

Been asked to check some one's house electrics, lots of DIY stuff. Nearly all sockets up and down are on radial circuits and 2 circuits going into each MCB. Bad points doing it this way?

 

[qiwutido]

Hello and welcome

 

[R-fur]

Nothing wrong with radials as long as they are installed correctly.

 

[Spoon]

Welcome to the forum mate.
Multiple circuits into 1 breaker is against the regs. (314.4)

 

[biggles74]

Welcome to the forum mate.
Multiple circuits into 1 breaker is against the regs. (314.4)

Thanks spoon, I knew it would be. Oh dear.

 

[telectrix]

there's no reg. that prohibits 2 radial branches becoming 1 circuit in the same MCB. as long as the MCB rating is selected according to the circuit cables.

 

[biggles74]

there's no reg. that prohibits 2 radial branches becoming 1 circuit in the same MCB. as long as the MCB rating is selected according to the circuit cables.

If you look at 314.4, each circuit has to be separate as to not enagise accidentally.
[automerge]1591360366[/automerge]

there's no reg. that prohibits 2 radial branches becoming 1 circuit in the same MCB. as long as the MCB rating is selected according to the circuit cables.

If you look at 314.4, each circuit has to be separate as to not enagise accidentally.

 

[telectrix]

if 2 radials are connected to the same breaker, they then becone 1 circuit. see definition of a circuit. ( page 26. 1st line. 18th Ed. BS7671)

 

[Spoon]

if 2 radials are connected to the same breaker, they then becone 1 circuit. see definition of a circuit. ( page 26. 1st line. 18th Ed. BS7671)

Come on.... Who would put an upstairs circuit on the same breaker as the downstairs one and just call it 1 circuit.

Ok , it also goes against reg 314.1

 

[Zerax]

Reg 314.4 refers to "Final Circuits"... If you read the definition of "Final Circuit", it's a circuit connected directly to current using equipment.

However, the definition of "Circuit" is an assembly of electrical equipment supplied from the same origin and protected by the same OCPD.

So a radial circuit as we know it, is both a "final circuit" and a "circuit".

So, according to BS7671, you can and cannot have >1 radial off the same OCPD.

 

[Spoon]

So, according to BS7671, you can and cannot have >1 radial off the same OCPD.

But you would go through the regs logically.
Once you get to 314.1 you will see that it's not allowed.... Would you then ignore this and twist the wording of 314.4 to suit your needs?

If that is the case then all future 'Power to shed/garage' threads we will just tell them to bung a 4mm one of the existing 32A breakers. This will stop Part P, as it's an existing circuit and they can also have 32A in their shed/garage, and call it 1 circuit......
We can also get BS7671 fig 15B changed to show multiple lines coming back to the breaker.

 

[telectrix]

does not alter the fact that 2 radials into the same breaker are "1 circuit". loads of lighting circuits where they are doubled up in small CUs as there are no spare breakers.