adding shower CU

[ianphilip007]

hi

just wanted to check something,
when adding a seperate shower CU (split tails) from a 80amp or even 100amp main supply the tails feeding the shower CU do they have to now be 25mm? or will 16mm be adequate due to the fixed load of the shower

The seperate shower cu (63amp 30ma RCD) is this again due to the CU supplying one fixed load so no need to be rated at the 100 or 80amp supply fuse

many thanks

 

[Snapester]

Yes i won't give overload protection hence the need for MCB along side the RCD.

 

[ianphilip007]

yes the mcb will protect the shower cable but i was mistakenly thinking that the rcd switch/current rating would have to be 80 amps for a 80amp supply fuse but if it is a fixed load of only 45amps then thats the maximum the rcd would need to be rated at.

 

[Snapester]

Exactly so if the shower is only ever going to have a max load of say 50amps then 63amps main switch is fine as your not exceeding what can safely pass through the switch.

 

[ianphilip007]

lol exactly thanks snapster.

 

[Guitarist]

Glad we cleared that up for you :star:

 

[ianphilip007]

many thanks for all your help