RCD shinaniginzzzzzz

[John tomo 1972]

did an RCD test today on a cu and when I went to reset it the left hand RCD tripped. No tripping when circuits up an running just when I did the RCD test could anyone give me a heads up on what it could be thanks guys.

 

[Andy5678]

Big fingers?

 

[John tomo 1972]

Lol ,

 

[Octopus]

Probably got earth leakage on 1 or more circuits ...

Have you got a earth leakage clamp meter?

 

[John tomo 1972]

No should I invest in one or is there another method of finding out

 

[Andy5678]

As murdoch said.

Also Have you tested both RCDs fully and ramp tested?

 

[Octopus]

No should I invest in one or is there another method of finding out

You HAVE to invest in one ..... it’s not optional

 

[Wilko]

Not sure I've understood ... tested the RH RCD and it tripped as expected - then - reset RH RCD and LH RCD tripped immediately.
Is that it?

 

[John tomo 1972]

Yep that’s it

 

[bigspark17]

Were you testing both rcds at load out side of the rcd with no load connected?

 

[John tomo 1972]

Just testing at socket , tripping fine just that when I reset it the other RCD tripped

 

[Richard Burns]

Possibly a high resistance neutral earth fault on the left hand RCD circuits. Remove the neutrals from the left hand neutral bar, left hand MCBS off and switch on the right hand RCD, mcbs on, and see if the high initial current trips the left hand one, reattach one at a time to narrow down.

 

[LankyWill]

Disconnect the neutrals and earths for the affected RCD and then it should reset. Reconnect until the offending circuit is found, im surprised you haven’t stubbled across this type of fault before.

 

[Risteard]

You HAVE to invest in one ..... it’s not optional

To be fair it's something I almost never use. I'd use it as an ordinary clamp far more than as a mA clamp. I wouldn't really consider it an essential piece of equipment for most applications.

 

[Octopus]

To be fair it's something I almost never use. I'd use it as an ordinary clamp far more than as a mA clamp. I wouldn't really consider it an essential piece of equipment for most applications.

When diagnosing RCD tripping it's an important measurement to take ....

 

[Deleted account]

Just testing at socket , tripping fine just that when I reset it the other RCD tripped

If it tripped when resetting that is a possible indicator of a loose connection inside the board.
When pushing up the rcd it may move the components within the board, thus making any loose connections worse, thus the trip.