We need an Rcd installing on our property. We have had an electrician round but to be fair I dont think he knew his beep from his beep!! Instead of replacing the consumer unit can we have a seperate Rcd protecting the full consumer unit?
There are many RCD's I have two feeding two consumer units both 30ma been there for years. But if everything goes through same RCD you may have a tripping problem first question is why do you want RCD,
a) Personal protection
b) Fire protection
c) Earth loop impedance not good enough
first type is 30ma at 40ms and if it covers whole unit may cause problems the other two can be between 100 and 500ma and type S and would not be likely to cause problems.
Some consumer units will take RCBO's and some RCBO's are two unit width others only one. You could fit sockets as well and then we have active and passive with the active type they trip with power cuts.
Cost is a consideration and look at screwfix and see all the types. But to fit RCD protection to wet room would cost only Â£30 less than changing whole consumer unit. So you need to think about if external unit is worth it.