Mcb tripping when shower not in use

[sparky b]

Hi, have been asked to go and take a look at an electric shower circuit that trips mcb when shower not in use.

Was wondering if there suggestions/ideas as to what to look out for, it's been tripping out over night but only the mcb, not rcd. As far as I'm aware no other circuits are effected.

Many thanks

B.

 

[Lee321]

have they got rats

 

[sparky b]

The thought had crossed my mind, but apparantly not. but here in oxford we've been having some extremely wet/windy weather and the cu is under a large sometimes leaky window, but i'd have thought other circuits would be effected if it was water penetration.......

 

[ianmacd]

Into the CU then yes but what about into the cable somewhere. Does the cable run up the cavity?

 

[sparky b]

As far as I'm aware it's surface mounted in trunking except for where is passes through the ceiling...

I'm thinking the shower unit could be leaking and the leak would be worse when shower not in use?

 

[ianmacd]

The pressue would be greater on any failing joints when not running but not sure why it would trip over night in that case.

 

[matt.leung]

i am correct, when u said that it trips when it is turned off....

 

[Lee321]

The pressue would be greater on any failing joints when not running but not sure why it would trip over night in that case.

:x

i am correct, when u said that it trips when it is turned off....

i think matt he means while its off. i.e in the night. not at the exact time when switching off.

is that what you meant?

 

[sparky b]

Sorry guys, i meant when it's not in action, not when it's being turned off...

 

[Lee321]

change the mcb i would

yoda was here ; \

 

[sparky b]

Strong in this one it is....

 

[superspark]

check inside isolator for shower and connections in shower maybe burnt cable.

megger circuit from db to isolator with sw off because neon will give false reading.

then megger leg from isolator to shower. prove cables ok

chheck connections at mcb.

thats what i,d do and think you will find somthing

if that fails run off:run