radial rcd

[ezekiel]

adding addition to radial in bedroom (no rcd protection at all)

planning on mounting a seperate rcd next to cu but need to know

20a mcb in cu using 2.5 to 30ma rcd but unsure of the a rating of the rcd does it need to be same or higher than mcb or does it not matter as its earth leak protection im concerned with,
the reason i ask is my local store only has 40a 30ma rcd and up in store, would this be ok?

 

[ericmark]

adding addition to radial in bedroom (no rcd protection at all)

planning on mounting a seperate rcd next to cu but need to know

20a mcb in cu using 2.5 to 30ma rcd but unsure of the a rating of the rcd does it need to be same or higher than mcb or does it not matter as its earth leak protection im concerned with,
the reason i ask is my local store only has 40a 30ma rcd and up in store, would this be ok?

40a 30ma if fine. Other option is use spur rather than radial and use

available from screwfix or use ali-tube cable and

 

[ezekiel]

thanks eric, can you explain why discrimination is not an issue ie:
20a mcb onto 40a mcb (assume its because im only addressing the rcd side?)

 

[ban-all-sheds]

40A is the current it is designed to carry, i.e. what it can safely switch if it trips. It doesn't provide any over-current protection, so discrimination with other over-current devices is not relevant.

Have you considered the option of replacing the MCB with an RCBO?

 

[ezekiel]

cu is old rewireable (wylex) can i get a rcbo for these?

 

[ban-all-sheds]

No.