Trippy RCD

[Jonnyboy 68]

Hi All..

Just got back from answering a cry for help from my new neighbour round the corner who's been sitting in darkness. They've been there for about a month now with no probs. House was supposedly re-wired before they bought it with new 17th ed board. There is a EIC, but only covering the board installation. 2 RCD's 6 circuits each , 1 keeps tripping out. In my PJ's with torch in hand .. I've had 30mins on it and I've narrowed it down to the cooker circuit. RCD is happy until the cooker is turned on at the cooker switch. Do nothing.. Give it about 15 secs .. and the RCD trips. House is TT, Ze 21.8 ohms.. R1+R2 0.18 ohms Insulation is good ....Tested RCD.. ramp test and 1/2, 1 and 5 X and all looks OK ?? Ive left the cooker circuit off for now and the RCD is a Happy Bunny again.. I'll pop back tomorrow when I've had some kip and have a proper dig about..... I'm a bit puzzled by the pause before it the RCD trips ??? you can almost set ur watch by it.. Any ideas ??

 

[kme]

Borderline leakage; or the PCB has a duff capacitor which charges when turned on, THEN trips when it reaches saturation?

If the latter, a megger test will only pick it up if you keep the test on for the same length of time - if the reading suddenly drops away; you`ve got `im.

KME

 

[Sidewinder]

Borderline leakage; or the PCB has a duff capacitor which charges when turned on, THEN trips when it reaches saturation?If the latter, a megger test will only pick it up if you keep the test on for the same length of time - if the reading suddenly drops away; you`ve got `im.

KME

Had similar to this with the heater on a tumble dryer, tripped rcd when heater went to cool down at end of cycle only!

I know it sounds stupid as the heater went off, but as it did it tripped the rcd!

Paul

 

[batty]

Moral of story put ovens/cookers through RCBO's Not RCD'S.

 

[roys]

Had similar to this with the heater on a tumble dryer, tripped rcd when heater went to cool down at end of cycle only!I know it sounds stupid as the heater went off, but as it did it tripped the rcd!

Paul

Maybe because as it starts to cool down it will draw in moisture, just guessing.

 

[ProDave]

Yes sounds like a fault inside the cooker.

Last time I encountered this, I told the customer it was unlikely I could fix it, but I would have a look anyway.

I took the back off the cooker, and there, across the mains input terminals was a dead mouse!!!!

 

[green-hornet]

Good points made here that will make me think about any possible links to any faults I may come accross

 

[PC Electrics]

Hi All..Just got back from answering a cry for help from my new neighbour round the corner who's been sitting in darkness. They've been there for about a month now with no probs. House was supposedly re-wired before they bought it with new 17th ed board. There is a EIC, but only covering the board installation. 2 RCD's 6 circuits each , 1 keeps tripping out. In my PJ's with torch in hand .. I've had 30mins on it and I've narrowed it down to the cooker circuit. RCD is happy until the cooker is turned on at the cooker switch. Do nothing.. Give it about 15 secs .. and the RCD trips. House is TT, Ze 21.8 ohms.. R1+R2 0.18 ohms Insulation is good ....Tested RCD.. ramp test and 1/2, 1 and 5 X and all looks OK ?? Ive left the cooker circuit off for now and the RCD is a Happy Bunny again.. I'll pop back tomorrow when I've had some kip and have a proper dig about..... I'm a bit puzzled by the pause before it the RCD trips ??? you can almost set ur watch by it.. Any ideas ??

So, not rewired then just a new board.

 

[Andy™]

So, not rewired then just a new board.

years ago when working for the council, ive been in many houses 're-wired' by a large national company, where the 're-wire' consists of a new board, and new sockets. and sometimes light switches. and sometimes lights, if they had any on the van.

even had an EIC in my hand at one time for a full re-wire, split load, all new circuits etc. only to find it still had a 4 way 3036, and no electrical work had been done

 

[ProDave]

even had an EIC in my hand at one time for a full re-wire' date=' split load, all new circuits etc. only to find it still had a 4 way 3036, and no electrical work had been done[/quote']The technical term for that is Fraud.

 

[Jonnyboy 68]

Hi,

had a good dig about today and probably wished i hadn't .... the dreaded kitchen fitters have been in inspired form on this one. JB's.. balls of masking tape with a connection block lurking deep within ...I'm sure you've all seen examples in your time.. DEF not a rewire .. Anyway , we've righted a lot of wrongs and I've earned my complimentary box of stella artios !! As for the cooker circuit ..mmmm... I'm forced to concede to the faulty appliance theory ... just can't find anything else on the circuit ..... Oh ..No dead mice around there Dave !!!! Having the RCD hang on like that was a new one on me .. haven't come across that before ... Anyway enjoy the weather boys and thanks for all your input .... Guinness

 

[sparky b]

Had a similar(ish) thing once, every time electric shower was turned on rcd would trip. Absolutely nothing wrong with shower, it turned out to be a faulty electric heater causing the imbalance but not enough until extra load (shower) was put on the installation.....

 

[Evans Electric]

Oh to go back to the 16th !!!!

 

[Badger]

Oh to go back to the 16th !!!!

ray :Applaud

 

[kme]

If this job didn`t have challenges, more numpties would do it, and we`d be out of a job.

The more difficult & convoluted they make it, the more work WE get, because there are less people capable of doing it.

KME

 

[Andy™]

The technical term for that is Fraud.

yes, but even after management was told about what was happening, they still gave the work to them. IIRC, they did at one point 'sack' the other company. for less than a week.