low ze's and a consumer unit question Ask questions and find answers to many subjects relating to electrics and electrical work

[davino]

tested a house today its a tns system and the ze was 0.03, the r1r2 on all circuits are good and the zs on all circuits also fall in line,, is this a the suppliers issue and is it dangerous.. sorry for sounding dumb but am a noob to testing..
also the board thats fitted has a 63a 30ma rcd and the lights have a 30ma rcbo but its not a split load board... will this present any problems
thanks

thanks
________
XJ600

[ericmark]

The Ze seems very low I would measure PSC and calculate the Ze to confirm reading. TN-S supplies to a house would normally be a lot higher I have had zero reading for Ze where the 3.3kv transformer was just the other side of the wall but the PSC reading although high was more valid and I used that.
Are you saying the RCBO is protected by a RCD if so there is no danger but neither is there any discrimination. As to complying with regulations it would depend on how often it tripped out.
Eric