Shower tripping rcbo?

[whazza22]

Replaced an mcb with an rcbo for a shower as the client wanted the extra protection without replacing consumer unit.

It's a 40A rcbo in 6mm for an 8.5kw shower. Approx 15m run from garage to shower.

As soon as the shower is turned on it trips the rcbo

Any ideas?

I didn't have any testers to test cable, possibly poor insulation.

 

[Sparky Ninja]

Too many variables. Did you give the RCBO a test when you installed it?

 

[kmcgold]

have you done any testing?

test rcd first could be faulty
but without a tester ?

 

[whazza22]

Only tested the rcbo using the test button and was ok

 

[whazza22]

And it didnt trip with the shower isolation turned on, only the second shower was switched

 

[SimpleSimon]

And it didnt trip with the shower isolation turned on, only the second shower was switched

Do an IR test on all conductors. That would help narrow it down.

 

[Sparky Ninja]

Use a tester and finish the job.

 

[whazza22]

It was a quick job for family member so had no gear on me. If insulation is fine then what else could it be? How could I test the rcbo? It's fine on a 40a mcb

 

[Octopus]

It was a quick job for family member so had no gear on me. If insulation is fine then what else could it be? How could I test the rcbo? It's fine on a 40a mcb

Hum. Back to school?

 

[whazza22]

Only just come out of school haha dont do much installing hence a bit ignorant

 

[SimpleSimon]

Do the tests first mate than come back if it ain't that n we'll scratch our heads sone more
Ps remember to disconnect the RCBO when IR testing.

 

[telectrix]

could even be a faulty shower. or is that too obvious? if it's a split board, is the neutral from the rcbo in the correct neutral bar?

 

[Marvo]

Maybe check the a neutral hasn't been 'borrowed' from the shower circuit if the installation and the shower itself check out okay.

 

[whazza22]

It's a brand new shower and the cables are approx 10 years old, installed by someone else. I told them I would get a test kit from work and test the circuit. My gut says poor insulation as rcbo is also brand new.

 

[cbw]

What have you installed the rcbo into......ie non rcd board or split load etc

My gut is poor installation either yours or previous, shower is new and cable is relatively new