Residual Current v Earth Leakage

[Timotei]

I think I must be missing the blindingly obvious, but.....

TT system......100ma time delayed as main switch, then some final circuits (which will require 30ma RCD as includes sockets etc)...then 30ma RCD for other final circuits...

Prior to changing CU at customer's request to include 100ma time delayed and 2 x 30ma RCD I have tested for earth leakage using clamp meter....(amongst other pertinent tests inc IR which is overscale on all circuits)

clamping LN tails gives 20ma as "regular" reading....lots of tv's / computers / fridges etc, so not entirely surprised by cumulative leakage...

but if boiling kettle, LN reading rises to 45+ma....so tested kettle using "stripped" extension lead technique, again clamping LN, to show 2-9ma max reading, but mostly 2-3ma.....and measuring on CPC only mirrors this result...

so why is increased residual current at tails so much higher than that measured "at source"?

have to admit to having tough time personally at the moment, so mind not as fresh as it should be.......hence opening statement about missing the blindingly obvious....

Thanks in advance,

Timotei

 

[DPG]

My nan's house had lead pipe up the drive, through the yard and up to under the kitchen sink. She lived to 101. A bit of lead won't kill you.

I should add that I have no concrete medical background to back this up, before anybody starts chewing lead pipes.

And don't lick asbestos.

 

[pirate]

Definitely don't lick asbestos...impossible to get it out from those interproximal spaces...spoils the taste of your gin and tonic!