Any thoughts on this old thing?

[timhoward]

Quite old main switch RCD, it occasionally trips (every day or two), then won't turn on until all breakers are off.
Ramp test at time of testing was 25ma, earth leakage meter said 5ma (so consistent).
Is the RCD likely to simply be old?! Are they tetchy switching on under load?

Haven't got into IR testing yet. Their initial enquiry was for a CU change so a DP RCBO board will likely solve all issues or worst case show up anything that has intermittent faults.

 

[Dustydazzler]

. I have an ex council estate near me where most of the houses seem to have those mem boards with the funny handle RCD. i have had a few times when doing an EICR done my trip time test on the RCD and the RCD trips and literally breaks and the switch just goes floppy. its was a good job I live locally and used to keep a small inventory of boards in my garage to do a quick emergency board change.

 

[timhoward]

Thanks. Yes, floppy is exactly the word! Then with the breakers off it worked again. And it did this twice….

 

[Dustydazzler]

I don't trust them old RCDs at all , to the point I recommed a board change before doing anything more...

 

[happysteve]

Still for sale if you want it?

 

[timhoward]

Still for sale if you want it?

View attachment 109618

Might pass on that one thanks!
Made in West Germany - pre 1989 then!

 

[brianmoooore]

OP's RCD tripping immediately when switched on with RCDs on is probably the residual leakage plus a capacitive surge as all the wiring 'charges up', plus possibly a bit of E -N leakage somewhere causing a pulse.
The 'floppy handle' is the mechanism that stops the RCD being held on against a fault sticking in the disconnected state. Usually caused by failure t regularly test the RCD with the button, and normally cured by a bit of 'exercising' of the mechanism.
In a couple of decades time, I'd trust a 50 year old RCD labelled made in West Germany against a 20 year old one labelled made in PRC.

 

[timhoward]

Thanks Brian.
They have decided to change it to a double pole all-RCBO Fusebox effort. As one of them works from home the nuisance tripping is quite an erm... nuisance.
I'm hoping that the process of the board change (IR testing etc) will reveal some likely candidates for the issues, that the division of the leakage will improve matters, and in worst case one circuit will trip. We'll see!

 

[SparkySy]

I was called out to a nuisance RCD tripping, yesterday, not one of those but a wylex one.
Did some tests and the ramp told me it was tripping at 21ma.
Turned the circuits back on 1 by 1 with a clamp on the main tails and watched the leakage reach 19ma!
The place was absolutely full of tec, chargers plugged into multi gang adaptors, half of them unused it turned out.
Got the final reading down to 12ma by the time the client and I had been round every room.
Got to quote for a full RCBO board for that job, 4 socket circuits, cooker, shower, immersion and outside man cave all on one 63a RCD!

 

[timhoward]

Now changed the board. Two 0.0x IR readings, one traced to outside light, the other on upstairs sockets which soared when a highly mangled iPhone charging cable was removed from a USB socket.

It's the first time I've changed one of these, and I rather liked the old board....it felt well made.
I appreciated the effort the original installer went to:

Only one complaint - can anyone spot it?

And in with the new:

(Let's see if a conscious decision I took attracts anyone's attention!)