Hi folks,

My family and I are living in a terrace house.
Recently my dad changed our 25-yr old voltage-based ELCB to a newer current-based RCCB (Wylex 2Pole 40A with 100mA sensitivity)

After that it start nuisance tripping a lot during storms, even if the lightning is far away.
When no storm, everything is OK.

I was surprised even 100mA also trips a lot, if 30mA of course I can understand the tripping.

Any RCCB users here on 100mA sensitivity? Do yours trip frequently during storms? If yes, what did you do to mitigate the annoyance?

This post has been edited by socratesman: Mar 15 2011, 12:30 PM

disconnected mine for the same reason. 100mA provides no safety anyway to humans. neither does 30 mA - you would need max. of 10mA for that.

Probably fault happened to your earthing....nobody use 10mA sensitivity at home lar...

nope all is perfectly well. and 10 mA is the recommended trip threshold in europe. any higher and its deadly for humans anyway so there is little point in having the ELCB for the purpose of saving a life anyway.

ermm...i said 100mA

change to better brand of ELCB/RCCB...GE, Hager....

IEE now states RCD (previously ELCB/RCCB were used).

10mA - 30 mA. Trip within 30 ms for shocks to person.

Protection against fire- up to 100mA.

Should use surge arrestor to protect your home.

use 300mA la then...
less tripping

You can use 300mA for the main incomer however not necessary protect against lightning.

Maybe there's something wrong with your wiring.. some leakage somewhere..

Install auto reset ELCB

Hi,
Saw your msg above while searching for solution to frequent lighning power trip.
I encountered exactly the same problem using the same RCCB/ELCB from MEM.
Did you find a solution?
If so, would appreciate if you can share it with me.
Thank You
Have a nice day.

instead of 40A type maybe try using the 63A type.

Tks for the input.
I am already using the 63A type.
Here is the spec on my MEM RCCB

Manufacturer: MEM
Model:632ELMN
In=63A
Ioan=100ma
Un=240V~

Would it help if using Ioan of 300ma or 500ma?

Thank You

This post has been edited by helob: Oct 30 2011, 02:41 PM


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In = 40A / 63A indicates the Max carry amp of the RCCB. It means, if you install a 40A RCCB, but you are running 50A of load, it will trip. This protect from overload.

Ioan is the sensitivity of the RCCB. Ideally, Live + Neutral = 0, if Live + Neutral /= 0, leakage happen. But, there's no ideal in real life, so, comes the Ioan where it is the tolerance the device will accept before registering the leakage as a fault, in your case, 100mA.
Generally, for lighting circuit, 100mA is used, 30mA is used for power circuit and 300mA for Air-Con.

As for your problem, how old is your house, particularly, the electrical wiring? The older the wiring, the higher the probability of leakage through wires due to degration of the insulator.

Proper solution, do a complete insulation test to the whole house, or change all the wiring. Improve your house earthing system.

Cheap solution, which profesional do not agree, but client will usually do due to cost saving. Use higher tolerance RCCB or use ELCB instead.

No matter how do it, make sure other than the fuse, there's at least a protection device in place.

Thanks for the very informative feedback.
My house is well over ten years as I bought it ten years ago.
You are most probably right that some wire insulation has degraded to a point where there is earth leakage during lightning which trip the RCCB.
My thought was to isolate certain area/wiring where leakage is suspected by selectively turn off the DPN MCB during lighning.
What is the best method of identifying the area/wiring other than doing a complete insulation test for the whole house?
Typically how long and the cost of doing a complete insulation test for a semi-D single storey house?
I thought RCCB is the current version of ELCB.
Pls elaborate on "use ELCB instead"
TQ and have a nice day.

why nobody mention about grounding.. there was a thread about this and most replies mentioned about improving the wire grounding..

didn't realise helpful helob resurrected my thread lol

After some research, I suspect background leakage from the internal wiring (my house is 30+ yrs old).
Say, maybe about 60-70mA worth of background leakage between Live and Neutral.
So the tiniest of surges from lightning could be enough to send the Live-Neutral delta over 100mA => TRIP

damn, now must check all the circuits in the house..mafan

Insulation test is very tedious job. Have to dismantle all lighting and power point from its appliances, and it might damage your existing wirie insulation since during insulation test, 1kV(can set to 500V) will be injected to the circuit to stress the wiring. If your wire insulation "almost going to die" after the injection, most probably going to "die" for good. We only do insulation test if the house wiring is still new, or when we know which particular circuit giving the problem. Not to mention, i don't think your local neighbourhood electrician know what is "insulation test".

RCCB are replacing ELCB and both are two different thing with different protection method which you can easily google it up.

One of my suggestion is to improve the earthing system as well. But it will involve lots of $$ especially lately where copper price are still at it high side.


As i suggested earlier to helob, either change the house wiring, use less sensitive RCCB, use back the primitive ELCB, improve your earthing system, or change to other protection system such as using adjustable ELR with a shunt trip coil, or just leave it as is, standby at the DB during thunder.

What is your findings so far?
Care to share!
Tks