Multiple 2.5mm radials from 4mm radial

[tubdub]

Refitting my kitchen and have come across this slightly odd wiring setup.

A grid switch for the kitchen appliances is fed by a 4mm radial on a 32a MCB. From the grid switch there are 4 separate radials in 2.5mm that feed a single socket each.

Initial thoughts are it's bad, but as each spur only feeds 1 single socket, each one would be protected from overload by a max 13a fuse in the plug, and the 4mm is protected by the 32a MCB.

So while it's not standard, it seems everything is safe from overload, so is it acceptable? I don't want to rip it all out if I don't have to.

Thanks!

 

[pete01]

Sounds ok to me

 

[ericmark]

The regulation says:-

433.2.2 The device protecting a conductor against overload may be installed along the run of that conductor if the part of the run between the point where a change occurs (in cross-sectional area, method of installation, type of cable or conductor. or in environmental conditions) and the position of the protective device has neither branch circuits nor outlets for connection of current-using equipment and fulfils at least one of the following conditions:
(i) It is protected against fault current in accordance with the requirements stated in Section 434
(ii) Its length does not exceed 3 m, it is installed in such a manner as to reduce the risk of fault to a minimum,
and it is installed in such a manner as to reduce to a minimum the risk of fire or danger to persons (see also Regulation 434.2.1).

This is often ignored with spurs, I have seen them much longer than 3 meters, and the regulations for ring finals

433.1.5 Accessories to BS 1363 may be supplied through a ring final circuit. With or without unfused spurs, protected by a 30 A or 32 A protective device complying with BS 88-2.2. BS 88-6. BS 1361. BS 3036, BS EN 60898, BS EN 60947-2 or BS EN 61009-1 (RCBO). The circuit shall be wired with copper conductors having line and neutral conductors with a minimum cross-sectional area of 2.5 mm² except for two-core mineral insulated cables complying with BS EN 60702-1, for which the minimum cross-sectional area is 1.5 mm². Such circuits are deemed to meet the requirements of Regulation 433.1.1 if the current-carrying, capacity (Iz) of the cable is not less
than 20 A and if under the intended conditions of use, the load current in any part of the circuit is unlikely to exceed for long periods the current-carrying capacity (Iz) of the cable.

does seem to say it is OK, and many consider 433.2.2 to be really for switch rooms, so personally I would say nothing wrong with the set-up, and it would not worry me. It was a standard set up years ago when washing machines could get loose weights and walk around the kitchen demolishing anything in their way, but today they auto turn off if out of balance, so problem is removed, also there were some freezers which did not have an off switch on their panel, so to defrost you needed a local switch. So the switch panel often with names on the switches became very popular at one time.

 

[EFLImpudence]

The regulation says:- This is often ignored with spurs,

That's because you continue to read it wrongly despite having been repeatedly reminded.

433.2.2 The device protecting a conductor against overload may be installed along the run of that conductor if the part of the run between the point where a change occurs (in cross-sectional area, method of installation, type of cable or conductor. or in environmental conditions) and the position of the protective device has neither branch circuits nor outlets for connection of current-using equipment and fulfils at least one of the following conditions:
(i) It is protected against fault current in accordance with the requirements stated in Section 434
(ii) Its length does not exceed 3 m, it is installed in such a manner as to reduce the risk of fault to a minimum,
and it is installed in such a manner as to reduce to a minimum the risk of fire or danger to persons (see also Regulation 434.2.1).