Crabtree RCCB and ZS testing

[Chris86]

Hello All,

After a bit of help regards ZS testing on a Crabtree Starbreaker board.

Have replaced 2 lengths of dado trunking in our office block at work and the measured ZS is coming out much higher than the calculated value.

Section 1 - calculated 0.5 ohms, measured 1.92 ohms.

Section 2 - calculated 0.42 ohms, measured 1.68 ohms.

I am convinced it's the RCD causing the higher readings so wanted to check ZS on incoming and outgoing terminals and compare the 2 but as it's Starbreaker with the internal busbar, there are no line terminals to test on. Is there any way I can test this or will I just have to rely on the calculated readings?

I have checked circuits supplied from the non RCD side of the board and the measured and calculated values are equal.

Sorry if it's a daft question but I haven't done a great deal of testing on domestic boards (we are factory based and all our stuff is Schneider or Red Spot 3 phase) and this is the first Crabtree board I have come across.

Thanks and ATB

Chris

 

[timhoward]

I know this is a really old thread, but to correct something for future searches, the Di-Log can in fact do a high current test, is it just stupidly obscure. Basically setting the tester to L-N makes it do a high current test. Join N and Earth together, either use both probes on earth conductor under test or join the leads together.
Di-Log themselves published this:

https://www.dilog.co.uk/wp-content/uploads/2016/11/9083P2-wire-high-current-loop-test-method-Mk2_000.pdf