4mm cable into the bottom of main switch.

[Steve93]

Eicr today had a 4mm T+E connected into the bottom of a main switch which went to a separate dB with 1 20amp rcbo. Then swa to a hot tub. That part is fine. What I’m unsure about is the reg I can say that the cables are not ok in the bottom of the main switch. The other dB is only about a ft away from the main one. What’s people’s thoughts on this? I know it’s rough as you like!!

 

[gazdkw82]

Sounds like you are inferring that a main switch and OCPD are one and the same?

No I'm saying the circuit originates from the main switch which IMO is inadequate protection. When designing circuits you choose a protective device to protect the entire circuit.

 

[Deleted member 9648]

No I'm saying the circuit originates from the main switch which IMO is inadequate protection. When designing circuits you choose a protective device to protect the entire circuit.

Not necessarily. The regulations permit omission of devices for both fault current and overload current under certain conditions, such as short tails to a DB at the intake. An OCPD on the load side of those tails effectively limits the current on the supply side. The same principle allows an unfused spur from a 32a RFC when effectively the CCC of the 2.5mm is around 26a. The fact that only one twin socket is permitted means only 2x13a=26a can be drawn.