Cooker circuit trips rcd mistery!

[sellers]

Just in the process of changing a board 2 cooker circuits 1 lighting and 1 socket circuit. 1 of the cooker circuits trips the rcd when the mcb is switched on, tested IR to earth and it's over 100meg, tested for borrowed neutrals and there are non? With the isolator off the rcd stays on but as soon as you switch it on it trips? Cooker IR's out fine, even with termostats on, rcd trips at correct times and at 23mA on ramp test, tested the 2g isolator and it tests out fine? Any ideas?

 

[steptoe]

Dodgy switch? Disconnect the neon and megger the complete circuit, switch and all.

 

[Andy™]

check other circuits for IR. low IR N-E fault elsewhere may not be enough on imbalance until higher load (i.e cooker, shower etc)

 

[sellers]

Had the isolator off the wall and tested the terminals? It's a strange one? Going to change the rcd mcb and connector block the cooker to see if it helps!

---------- Post Auto-Merged at 13:36 ---------- Previous post was made at 13:33 ----------

Only 1 other circuit on the same rcd and it's over 100meg too!!

 

[Andy™]

low IR on element but only low when it heats up? or only connected once there is mains power at the cooker

 

[Chr!s]

Does the circuit trip with the cooker disconnected?

 

[Manator]

My immediate thoughts would be a problem with the elements, I had a similar problem where the cooker would actually heat up for a bit then trip the RCD, after a while the fault disappeared along with the accumulated moisture I would guess.

 

[ktguk]

[quote name='Andy

 

[sellers]

Ok well, It's a little embarrassing! The circuit was fine the problem was when there was a load on either circuit! And all because the incoming neutral and out going neural in the rcd were switched around in the board! School boy! Lesson learnt!

 

[Andy™]

yep, that would do it!

 

[Evans Electric]

Easily done , we all make crock ups if truth were known, its sorting them that matters. Also , you'll probably never forget to check those links again.

I did an MK board last week , seemed to have blue flexible links everywhere, I always rip them all out when fitting boards , had to stop and think when replacing them.

 

[sellers]

it was an mk evans probably the same, think it was a 15way mk sentry, first time I've installed an mk consumer unit

 

[steptoe]

probably one that Deke fitted