RCD Tripping - Electrician can't help!!

[securespark]

Isn't there a reg that says something like, "thou shalt follow equipment manufacturer's installation instructions"?

 

[vincentbrown]

I have now moved both the cooker and immersion heater onto the non RCD side leaving 4 ring mains and the shower on the RCD side.

This has left me with enough space to fit another RCD and split the load which will then hopefully enable me to isolate the faulty circuit / appliance.

 

[suffolklad]

so vincent wheres the spark gone that fitted new cu in the first place ?.and why didnt you get him back to mend it ?

 

[JohnD]

I don't know if single-width Protek RCBOs are available, if they are, you might find them useful.

If money is less of a problem than time and inconvenience, you might think about replacing the CU with a MEM or other brand where RCBOs are readily available. Then you could discontinue the split-load configuration and have one RCBO for each socket-circuit.

 

[RF Lighting]

Yeah they are available, but I'd save the money and fit a decent brand of CU......


http://www.electricalwholesaler.org.uk/SWITCHGEAR_Low_Resolution.pdf (Page 66)


You can see the build quality.

 

[securespark]

Mmmm. Feeeeel the quality.....NOT!

 

[vincentbrown]

Suffolklad, I saw the electrician today to ask his advice again. To be fair, I think he generally knows his stuff, maybe he had a bad day when providing the Protek CU and wiring it the way he did!! He did conceed that there are too many circuits on the RCD and that possibly the mA's are just adding up. We discussed moving the circuits that I noted above and also splitting the RCD circuit into two.

Having said that, in his opinion, we do have a problem somewhere and he still maintains that he couldn't guarantee to find very quickly, if at all. He sited similar cases where faults subsequently discovered, didn't show up during testing.

I haven't an open cheque book and do not want to provoke an argument about who's fault this is. I certainly don't want to pay for a day's labour without a result.

I am more comfortable sorting this myself, I am a believer in the saying 'If you want something doing properly, do it yourself'. Unfortunately, my experiences of tradesmen generally is not good, I always seem to have to re-do the work after they have gone - but that's for another post maybe!

I agree that the CU is a bit naf but I now have it so have to live with it.

RF Lighting, thanks for the link, I will look through it more closely when I have time.

 

[suffolklad]

hi there vincent yes i agree if you want a job done properly do it yourself . problem is with all the regs in electrics and every other trade these days you tend to get a proffesional in who has papers but at the end of the day they mean nothing if the experience isnt there. a friend had same prob as you rcd tripping , took two sparks to find prob first one who had his papers all fancy test equipment couldnt find it . last one an old spark in in buisness 40 years plus but not up to todays regs found prob an old socket a live wire and very faint black mark on earth bar on back of socket where insulation was bad hardly see only just visible . i am surprised the spark didnt want to solve your problem for you

 

[vincentbrown]

Still tripping as and when it feels like . Rather than butchering the CU myself to fit a second RCD which would atleast enable me to locate the guilty circuit, (but at the same time obliterate the certification that I have for the installation ), I have made contact with another electrician (by recommendation), who is due to take a look on Monday morning. Watch this space!

 

[vincentbrown]

The electrician visited on Monday as promised and Megga(?) tested all of the RCD circuits individually and also combined. Guess what, he found everthing to be exactly as expected!

Both my old RCD and the new one also tripped as expected and within the correct time when under test.

However, he was concerned regarding the difficulty in resetting the new RCD after tripping (as I detailed in a previous post above) and infact after a number of forced trips, it was very difficult to reset. He therefore considered it a high possibility that I had purchased a new, but faulty RCD which has completly thrown me off track regarding the tripping of the original RCD which I considered to be caused by the tumble drier.

Following several unexplained trips over the weekend, we have put the original RCD back in place and we are leaving the tumble drier unplugged. So far, we have had no trips this week.

I have returned the suspect brand new RCD back to the supplier!!

 

[securespark]

How is he testing this RCD??????

 

[vincentbrown]

I terms of trip testing, he used his equipment to apply different mA's to see when the RCD triped and the time in which it did so. He did this with the RCD's in place and his meter pluged into a wall socket.

At 15mA, no trip was recorded on either RCD and at 30mA, both triped within an acceptable time (20msecs ?). He did several tests on each RCD and was happy with the results.

As far as determining the potential fault on the new RCD, it was purely based on it not resetting properly and the fact that with no obvious fault in the circuits, it had tripped approximately 15 times over the last week at completely random times.