rcd bust?

[Adie moore]

strange goings-on or it might be me, this is what happens;

• 3 lead loop test on final circuit = rcd trip

• 3 lead loop test at board, outgoing side of rcd, all circuits off = rcd trip

• 3 lead loop test at incoming side = rcd trip

• rcd test at outgoing side= X.5 no trip X1 45ms X5 29ms

•rcd test income side no trip at 500mA

• 2 lead loop test on incoming side = L-N and L-E both ~ .35ohms

why is it tripping on the 3 lead test, especially on the incoming side?

this is a remote board supplied by 16mm 3 c swa.
cheers.

 

[Octopus]

Did you ramp test it?

 

[Adie moore]

ramp on incoming side, no trip. didn't do it on the outgoing as results were ok.

 

[Wilko]

Hi Adie, I've only seen RCD trip from current going through it, so is there possibility of weird wiring? Or reversed leads (sorry - just clutching at straws). I was wondering what prompted you to try the RCD test before the RCD?

 

[davesparks]

I'd go with a slight N-E fault being the culprit here, test the RCD with the outgoing side disconnected (all conductors)

Why have you applied an RCD test to the incoming side of an RCD? I can't see the point of doing that?

 

[Adie moore]

I will be investigating further. re unorthodox rcd testing, I was just wondering if it would trip and thus give me a reading.
IR test L+N-E 12Mohm.
it was late so didn't dis connect all circuits

 

[davesparks]

I will be investigating further. re unorthodox rcd testing, I was just wondering if it would trip and thus give me a reading.
IR test L+N-E 12Mohm.
it was late so didn't dis connect all circuits

It won't trip if you RCD test on the incoming side, it will just put a current down the earth unnecessarily.

 

[Adie moore]

It won't trip if you RCD test on the incoming side, it will just put a current down the earth unnecessarily.

how does that different from a loop test, yet that still tripped the rcd from the incoming side.

 

[tony mc]

The difference is that a Hi loop puts 25A down to earth (Unless its a no trip 15mA)and the RCD test put whatever setting you have your meter set on mA!

The RCD should not trip so you need to find out what the problem are all the connections tight !