RCD not tripping at 1X 180 deg

[automationman]

Hi all, I am part way through installing/testing a new consumer unit (going back tomorrow to complete the testing)

Ground floor ring (2.5mm wire, 32amp MCB, Crabtree 30ma RCD)

RCD test does not trip the RCD at 1X, 180 deg (negative half cycle)
All other RCD tests are good including the 5X which trips in 23ms on 0 deg and 17ms on 180 deg. 1X, 0 deg is also good at 43ms.

I had to leave the site so I could not do any further investigations this evening but just wanted to get a head start on it for tomorrow. Do you think this could be related to capacitance in the circuit? As I write this I start to think that the boiler (combi) may be wired to a spur off this ring..... Could it be filter capacitance in the combi? But the 5X test works well... any ideas would be very much appreciated.

I'm using a Seaward PowerTest 1557, well inside calibration date and worked well last week on two smilar jobs.

Thanks, I'm new to this forum and there looks to be a lot of very good info and some smart people too (smart in the academic sense, don't know about your dress sense)

 

[RF Lighting]

Did you test the RCD in isolation, or with the outgoing circuits still connected?

 

[333rocky333]

and some smart people too (smart in the academic sense, don't know about your dress sense)

I will vouch for RF Lighting.
(He posted a picture of mimself in a SUIT once)

 

[martinxxxxxx]

I always isolate all loads when testing. Normally someone plugs one back in before I get started. Personally i would just swap the rcd over with a known unit. The point of the test is to catch things like this after all. I am sure more learned friends will educate us further, and i look forward to it.

 

[automationman]

With outgoing circuit connected. Was going to test in isolation (at the CU) but the house owner wanted to lock up for the night (empty property) Going back tomorrow. BTW, Ze was 0.19 (T-N-C-S)
Thanks,

 

[333rocky333]

Isolate, as in remove wires out of rcd in the Dist board.

 

[RF Lighting]

and some smart people too (smart in the academic sense, don't know about your dress sense)

I will vouch for RF Lighting.
(He posted a picture of mimself in a SUIT once)

It's probably still knocking about on the forum somewhere.

 

[automationman]

Some good points here, thank you. I really should test the RCD in isolation tomorrow and it may well be the RCD itself...

An electrician in a suit!!! that will surely generate more web hits than last nights X Factor!!

 

[333rocky333]

It's probably still knocking about on the forum somewhere.

I know where it is

Bans on it as well (Not sure it is him though)

 

[Steve]

It's probably still knocking about on the forum somewhere.

I know where it is

Bans on it as well (Not sure it is him though)

That one?

Couldnt find the original rogues gallery with ban on - perhaps I wasnt looking hard enough!

 

[ricicle]

Couldnt find the original rogues gallery with ban on - perhaps I wasnt looking hard enough!

 

[333rocky333]

http://www.diynot.com/forums/viewtopic.php?t=53877

All the others gone now unless you find Ninebobs website.

 

[RF Lighting]

Christ, nearly scared me to death then. I'd forgotten about this thread, and there I was

(I'm even more good looking in real life)

 

[JBPElectrics]

Are you laying on the floor of a swimming pool?

 

[RF Lighting]

It's a tiled wall and a slightly dodgy photo.