RCD Tripping Intermittently

[Ciaran Lang]

Hi,

I have a RCD in the CU connected to 2 x socket circuits (house and kitchen/heating), shower and cooker. This tripped the other night when only the heating and a couple of sockets were on. I reset this and the issue only reoccurred tonight. The RCD would not switch on until the kitchen/heating breaker was off. I thought this was the issue so when I turned the breaker back on I expected the RCD to trip but it stayed on. I tried switching everything off and back on one by one but nothing tripped the RCD.

I discovered that if all the CBs are on the RCD will turn on sometimes but trip when turning on other times. By that I mean repeatedly turning it on until it stays on.

Dos this this sound like a faulty RCD? I am going to buy one to rule this out.

Could it be any other issue?

Thanks in advance for the help

 

[shanky887614]

thanks marvo.

i understand they are different, and from reading the posts, it seems that on an intermittent trip scenario, they would be very useful. im just trying to understand when and how i/you would use ELCM and how it would speed up finding fault

on a permant fault rcd tripped, you can find fault using IR test ( how would/could a ELCM make things quicker )

sorry if im being particular, but im just trying to work out how much to spend versus how much would/could use

if you have got an intermitant fault it could be on say an element that only leaks enough when it gets upto temperature or on cheap electronics when its under load.
its one of those tools that most will only use once in a bluemoon but when in certain cases you will be glad you have it.

(i dont see the point in most people having them calibrated though)

 

[Octopus]

The "other" time the ECLM is useful, is when you are scoping a CU change - its useful to guage the leakage across the existing board!

 

[davesparks]

thanks marvo.

i understand they are different, and from reading the posts, it seems that on an intermittent trip scenario, they would be very useful. im just trying to understand when and how i/you would use ELCM and how it would speed up finding fault

on a permant fault rcd tripped, you can find fault using IR test ( how would/could a ELCM make things quicker )

sorry if im being particular, but im just trying to work out how much to spend versus how much would/could use

If the fault is permanent then an ELCM will be no use at all, the RCD won't stay on long enough to get a reading! This is when an IR test would be employed.
However an intermittent fault where tripping occurs at apparently random intervals will be easier to find with the help of an ELCM.

 

[Silly Sausage]

He doesn't need an earth leakage clamp...................

I think it shows your excellent fault finding skills myself.