tripped RCD

[david0173]

Hi All .A little advice if you please.Called to a tripped not resetting rcd tonight.The owner said that its been tripping for ages but they have just been resetting it now it wont.
On looking at the C.U.the RCD protecting two mcbs all wiring to rcd and circuits looks ok and tight. i switched off all the mcbs and then the board.switched main back on the mcbs on non protected side all good so far.tried to switch on RCD but wont switch on you get the green in window and as you move the switch up it changes to red but wont stay on this is without any load applied.left the rcd side all off only lights tonight.
Going back in the morning ,any thoughts would be great thanks

 

[FAA Greenie]

If there is definately no load on it, replace the RCD. I had a job only a few weeks ago where the guys RCD tripped every time he plugged any sort of charger in. By the time i had tripped it several times it just wouldn't reset just as you describe. Quick change, rest and job done.... Hopefully!! (So long as you are a competent person that is)!!

 

[spark 68]

If all the MCB's on that side have been opened, then it is possible you have a N to E fault, one of the favourites here is a N wire trapped by the pattress screw on an accessory to the backbox.

You will have to disconnect the Neutrals from N bar for the side in question to see if this is your fault (N-E fault), a circuit at a time to narrow it down.

 

[david0173]

thanks for the quick replys.going to pick up a new rcd in morning hopefully that will do it.If not its only two circuits to check so hopefully find problem reasonably quick seeing as its the weekend.
thanks again

 

[MarkieSparkie]

Hi David, It sounds to me as if you may have an MK RCD with the red/green indicator. MK and some other RCDs have a slightly different reset procedure to normal which can catch out the unwary. When this type of RCD trips the lever drops to a mid position and not fully down as is normal. If you just try to lift the lever from the mid position it will not latch. To reset the RCD it's necessary to first pull the RCD lever fully down and then lift the lever fully up where it should then latch.

 

[david0173]

Hi David, It sounds to me as if you may have an MK RCD with the red/green indicator. MK and some other RCDs have a slightly different reset procedure to normal which can catch out the unwary. When this type of RCD trips the lever drops to a mid position and not fully down as is normal. If you just try to lift the lever from the mid position it will not latch. To reset the RCD it's necessary to first pull the RCD lever fully down and then lift the lever fully up where it should then latch.

Thanks for that mate yes its a mk and i was aware of the reset procedure for that but thanks for the reply

 

[ezzzekiel]

would imagine there is a n/e fault and the rcd has given up the ghost from constant operation.
test rcd with no load, then disconnect neutrals and then ir test

 

[i=p/u]

would an ir test show up trapped neutral????

 

[Deleted member 19807]

first i would drop the neutral out of the rcd and see if it resets, if it dose test it, if not replace it. if it tests ok drop the neutrals out and re-fix one at a time until it trips. either the rcd is worn out after all that tripping or the piece of kit thats been making it trip has finally given up completly

 

[david0173]

Hi sorry for not getting back sooner.Checked the two circuits one ring fine not tripping the rcd,other ring trips when N put into N bar.Was going to split the ring and find fault but ring only suppyling 4 skts with plenty of space under the floor to get to them.Just put in a radial on a 20 mcb problem solved thanks for advice.

 

[ackbarthestar]

Hi sorry for not getting back sooner.Checked the two circuits one ring fine not tripping the rcd,other ring trips when N put into N bar.Was going to split the ring and find fault but ring only suppyling 4 skts with plenty of space under the floor to get to them.Just put in a radial on a 20 mcb problem solved thanks for advice.

So, you removed part of the second RFC, turned it into a radial and replaced the 32A MCB with a 20A MCB?
Presumably, a damaged leg back to the DB?