RCD requires a little rest before resetting

[happysteve]

Doing standard tests prior to some minor works on a socket circuit (Zs, IR etc), pressed the test button on the RCD, tripped fine, got ready to measure trip times but the RCD would not reset. Tiny bit of resistance as you first start lifting the lever, then goes completely floppy, i.e. you can lift the lever but it's not engaging with anything, and doesn't hold. Tried a few times but would not reset.

Disconnect the N out of the RCD, (all downstream circuits already turned off), and this time the RCD reset. "Ah!" I thought, "Maybe some pretty serious N-E fault is preventing me resetting it!" So like a fool I pressed the test button again - it tripped - and then wouldn't reset. Tried turning off the main switch - no difference, still won't reset.

So off I go to the van, to see if I've got something that fits well enough before I can get a matched replacement by the same manufacturer. By the time I come back from the van, I can reset the RCD.

At this point, I figure it just needs a little rest before being reset. Sure enough, I managed to do all the standard RCD tests, all disconnection times were well within spec, it just needed 2-3 minutes after tripping each time before it could be reset.

It is a Contactum B6303/2: BS EN 61008, 2-pole, 63A, 30mA, type AC.

Anyone experienced anything similar?

 

[ChrisElectrical88]

Yes with the exact same RCD. Changed a shower pull switch, did some basic tests and the RCD wouldn’t reset. Went to the wholesalers and picked up a newer contactum RCD. Got back, reilised the new one didn’t bloody fit and then the old one reset in my hand and tested out fine!

 

[pc1966]

Sounds like it is a "feature" of that design. To me it is a fault but if that is really the way they behave then I guess it is a pass. Just a tedious test to verify that.

 

[nicebutdim]

There are a pair of those RCDs not ten feet from where I'm sitting and never had any issue with resetting after pressing the test switch. Replaced one after about a year, when it became overly sensitive and progressively more difficult to reset after each trip.