Shower tripping sockets rcbo

[ThrownRazor25]

On call and the socket rcbo is tripping when the shower gets turned on.i have traced the shower cable and it goes from db to switch to shower.there is nothing connected into the sockets it is on a 40 a rcbo the sockets are 32a

The socket rcbo trips but the shower one doesnt.

Any thoughts?

 

[Taylortwocities]

Has it ever worked before? If not then I would suspect the neutral for the shower is somehow connected to the sockets RCBO.

Continuity test should show that.

 

[Pete999]

On call and the socket rcbo is tripping when the shower gets turned on.i have traced the shower cable and it goes from db to switch to shower.there is nothing connected into the sockets it is on a 40 a rcbo the sockets are 32a

The socket rcbo trips but the shower one doesnt.

Any thoughts?

Any testing done to prove anything???????

 

[ThrownRazor25]

There is no continuity between either rcbos

 

[Wilko]

Could it be a N-E fault on the 32A ring that is set off by the shower current? If so, a load in the 32A ring should cause trip too. Just a thought.

 

[ThrownRazor25]

It worked fine up until yesterday

 

[Pete999]

Could it be a N-E fault on the 32A ring that is set off by the shower current? If so, a load in the 32A ring should cause trip too. Just a thought.

What he said^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[tony mc]

There has been a few posts recently about RCBO RCD tripping when circuits not connected to that RCD have been energised!

Richard Burns has put up a diagram explaining how this could happen I will see if I can find it.

Have you tested both circuits fully and checked for any loose conections including the main switch?

 

[tony mc]

http://www.electriciansforums.co.uk/posts/1217461/

http://www.electriciansforums.co.uk/posts/1217441/

 

[ThrownRazor25]

Checked both circuits all switches/sockets tightened up all connections ir tested both and greater than 299mohms on all tests both circuits.

Turn shower switch on sockets trip

 

[Wilko]

Ramp test the 32A ring ?
Also, what happens if you turn the shower on at lowest setting?

 

[ThrownRazor25]

I swapped the 2 rings round hoping it would trip the downstairs ring ie faulty rcbo but no kept tripping the upstairs.

Wouldnt a ramp test just tell how much of a fault current is lifting the rcbo?still cant figure out why a sepwrate circuit is causing it to trip

 

[Wilko]

You are ahead of me ... the ramp test will help to find it if was on a hair trigger. You did that by changing RCBO

Can there be any connection between the cables of the ring and the shower somehow? Perhaps an IR check to confirm they are in fact independent?

 

[Midwest]

Have you tested the shower itself? Out of interest, what make is the RCBO?

PS have you tested RCBO's with circuits disconnected, to ensure they are functioning correctly ?

 

[Octopus]

I would get your earth clamp meter out and see what the leakage is.... you may be getting good IR results with appliances isolated but when they are turned on.....the leaking starts.....

 

[westward10]

Definitely need the shower switched on to test it.

 

[Octopus]

Definitely need the shower switched on to test it.

Not sure I agree with that.

I'd be testing the leakage first!

 

[Deleted member 26818]

What else is connected to the socket circuit which only comes on when the shower is on?
What is being leaked onto from the shower?

 

[Richard Burns]

The fault must be located on the circuit that the RCBO is protecting i.e. the sockets, because, unless the shower is cross connected into the socket circuit, then the RCBO cannot react to a fault on the shower.
The shower being turned on and tripping the socket RCBO means (some of, >30mA) the shower current is passing through a fault on the socket circuit.

 

[westward10]

Maybe through sup bonding ?