Any thoughts on this old thing?

timhoward · Jul 27, 2023

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.

[ElectriciansForums.net] Any thoughts on this old thing?

Dustydazzler · Jul 27, 2023

. 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 · Jul 27, 2023

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

Dustydazzler · Jul 27, 2023

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

happysteve · Jul 27, 2023

Still for sale if you want it?

timhoward · Jul 27, 2023

happysteve said:
Still for sale if you want it?

View attachment 109618

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

brianmoooore · Jul 28, 2023

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 · Jul 28, 2023

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 · Jul 28, 2023

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 · Aug 2, 2023

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!)

littlespark · Aug 2, 2023

That’s not the right bus bar shield, surely??

Dustydazzler · Aug 2, 2023

Its covering up half of the yellow rcbo test button

pc1966 · Aug 2, 2023

Maybe my eyes are deceiving me, but is it a cut-off CPC on the incoming T&E?

pc1966 · Aug 2, 2023

timhoward said:
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.

The charger must be broken then if it has primary (mains) to output (USB) lead continuity!?

Maybe I'm odd (OK, yes I am odd) but when PAT testing the likes of USB chargers, PoE injectors, etc, I treat "class II" testing with the earth clamped to a butchered USB/network cable so I can check for insulation failure inside. Thankfully not found a dangerous one yet, but you do read of the occasional death from that (often involving eBay fakes and a bath as well).

timhoward · Aug 2, 2023

littlespark said:
That’s not the right bus bar shield, surely??

Dustydazzler said:
Its covering up half of the yellow rcbo test button

It actually is the right shield, I just didn't fit it correctly before taking the photo. It's fine now (honest!)

pc1966 said:
Maybe my eyes are deceiving me, but is it a cut-off CPC on the incoming T&E?

Yes, that was the main thing. There's a separate 10mm CPC but I didn't like the T&E being un-earthed. I didn't want risk damaging the rather short incoming T&E so I earthed it the other end (also cut off) and there's now a wago on this end and a notional 4mm to the CPC bar.

pc1966 said:
The charger must be broken then if it has primary (mains) to output (USB) lead continuity!?

Yes, it was actually a plug in apple charger not a USB socket, my mind wandered!
The apple charge plugs are earthed, and I was getting a N+E fault show up. I binned the lot, but in hindsight some more tests would have been quite interesting, as it suggests a primary/secondary link/fault on one side of the coil.

The more minor thing that some would say is wrong with my install hasn't been spotted yet. It's related to an area of scrutiny that Westy specialises in....

loz2754 · Aug 2, 2023

I didn't know Westy specialised in the lack of grommet strips.

timhoward · Aug 2, 2023

loz2754 said:
I didn't know Westy specialised in the lack of grommet strips.

Fair! I was expecting some in the brown envelope and they were missing. I decided as the wall opening was higher than the lower edge I wouldn't lose too much sleep over it.

That still wasn't the thing I was thinking of though! It will be interesting to see how many more things I've done....!
It's something the original installer also did.

nicebutdim · Aug 2, 2023

Polarity reversed at incoming tails?

timhoward · Aug 2, 2023

nicebutdim said:
Polarity reversed at incoming tails?

Good God man you know how to make someone's heart skip a beat!
No, we both got that right!
(One of my biggest concerns was the length of the main N but it worked out ok, just!)

No, it's a very minor thing, as we all tend to be a pedantic bunch I was expecting someone to slap me for it straight away.
It would probably first be noticed if you had to test certain circuits.

nicebutdim · Aug 2, 2023

timhoward said:
Good God man you know how to make someone's heart skip a beat!
No, we both got that right!
(One of my biggest concerns was the length of the main N but it worked out ok, just!)

No, it's a very minor thing, as we all tend to be a pedantic bunch I was expecting someone to slap me for it straight away.
It would probably first be noticed if you had to test certain circuits.

Not familiar with that old incomer and didn't want to assume busbar connection to it, but lettering appeared to show 'L' above left terminal.

Dustydazzler · Aug 2, 2023

Bonding in the right hand earth terminals meaning every cicruit is shuffled to the left

loz2754 · Aug 2, 2023

Dustydazzler said:
Bonding in the right hand earth terminals meaning every cicruit is shuffled to the left

That's ok with this consumer unit. It starts numbering further along.

loz2754 · Aug 2, 2023

I didn't know Westy was a stickler for sharing earth sleeving with multiple conductors.

timhoward · Aug 2, 2023

Dustydazzler said:
Bonding in the right hand earth terminals meaning every cicruit is shuffled to the left

Ah they were a little short... and there are some spare terminals.

loz2754 said:
I didn't know Westy was a stickler for sharing earth sleeving with multiple conductors.

That's the one I was thinking of. And maybe he isn't, maybe it's just sleeving size?!

The original had the CPC's twisted together impressively tightly to the degree I didn't want to risk unwinding them.
So did testing at a socket and left them well alone.

Dustydazzler · Aug 2, 2023

If the cores are really short but just about reach one side of the bar then i will always do what you have done and just shuffle everything down / up to avoid jointing cables.

Likewise if the cores are alrteady twisted within an inch of their life it is often better to leave alone than risk unwinding them just to have it snap right at the top of the cable.

Don't teach stuff like this in the class room

-

-

-

-

-

-

-

-

-

-

-

-

-

loz2754

-

nicebutdim

-

nicebutdim

-

loz2754

loz2754

-

-

Similar Threads

OFFICIAL SPONSORS