Interesting Electric shower wiring

[Rocboni]

Came across a interesting method of wiring a shower, 6mm runs from mains position from a splitter with 40amp mcb and RCD when it reaches the ceiling space abouve bathroom, they have taken a 6mm to the shower switch and one to the shower and used the 6mm to the switch as a feed and return and jointed using a 30amp joint box, so only switching the live.

Not possible to rewire as shower room has been boarded, does not pass through any thermal insulation, and grouping isn't an issue as it has been added at a later date, separate holes for the complete length of run.

Can't see an issue with this other than the joint box isn't rated for 40'amps, advised them to upgrade the joint box to something rated for 4oamos, was thinking a 60amp joint box but they only have 3 terminals, need 4. Is the only option a joint box with 60amp connector strip? I haven't check the size of the shower.

 

[Ian1981]

Came across a interesting method of wiring a shower, 6mm runs from mains position from a splitter with 40amp mcb and RCD when it reaches the ceiling space abouve bathroom, they have taken a 6mm to the shower switch and one to the shower and used the 6mm to the switch as a feed and return and jointed using a 30amp joint box, so only switching the live.

Not possible to rewire as shower room has been boarded, does not pass through any thermal insulation, and grouping isn't an issue as it has been added at a later date, separate holes for the complete length of run.

Can't see an issue with this other than the joint box isn't rated for 40'amps, advised them to upgrade the joint box to something rated for 4oamos, was thinking a 60amp joint box but they only have 3 terminals, need 4. Is the only option a joint box with 60amp connector strip? I haven't check the size of the shower.

The manufacturers instructions may require a double pole switch for shower.
Think you've stated that only the live is switched/isolated by shower switch.

 

[Richard Burns]

Put a contactor in in place of the joint box and use the shower switch to operate the contactor? then you get DP isolation and a means of connecting the cables, unfortunately not really protecting to coil from overcurrent but a possible off the "ceiling" idea.

 

[Rocboni]

Just wondering if I can get another length of 6mm to the switch and just joint both through, creating a normal circuit.

 

[Richard Burns]

Just wondering if I can get another length of 6mm to the switch and just joint both through, creating a normal circuit.

If you can get a cable to the switch then that would be the most straightforward solution, just make sure all the terminations in the junctions are secure.