intermittant overall rcd fault

[uksel]

i always do an IR test on all the circuits before removing a CU to change it, any suspect readings and the changeover stops.

 

[bugsy]

Well Lloyd did you sort it

 

[lloyd1980]

just got back from there now guys
what a nightmare!!
IR tested all the circuits individualy with everything unplugged lamps removed, everything meggered out ok with good readings
then i ramp tested rcd - fine -
split rcd so I tested the other - fine
there were 3 original lives coming out the mcb id installed so i connected one with everything else off, and found the other live ( the ring) and dissed the other non live one including its neutral and just left the ring
this stabalised things with the ring, as in toaster kettle microwave all going and it was holding
tested what was dead to see what the dissed cable fed
it was a fan heater in his bathroom from a fused spur.
so at this point ring is ok
try the cooker, pop goes the rcd
i move the cooker over to the rcd thats holding with the ring try it again - pop
I megger the cooker cable again - >299 on meter so ok
im thinking faulty rcds, so spin down the wholesalers and change them, some back fit the new ones
exactly the same problem
all his impedances are excellent and everything meggers out like it should
I advised the old fella, that his work wasnt helping things, as in lots of lighting and flurecents wired in flex and double sockets he'd fed from plugtops all over in flex all neatly in trunking werent helping matters, he knew a little about electrics but was convinced he knew everything so how dare I question his work - even tho it was sh ite
I then told him I was getting a mate down as 2 heads were better than one and I would get to the bottom of it!
He instructed me to stop work there as he didnt want the extra cost of the investigation, and he instructed me to re-fit his rewirable fuse board
told him I could not sign this off as old board
he didnt care and insisted I did it
So i spent time then refitting his old board ( thanks god I didnt skip it yesterday) and got him back on
he then wanted to discuss the estimate as no new board - advised him I couldnt take it back to wholesalers as been used so cant knock it off the price
I tested his whole flat and refitted his old board at the original estimate cost (new cu) and have done loads more than I charged for
I just hope when his daughter goes round and sees the 17th edition board sitting there in his cupboard and the original one in and all it looks like hes had done is a new 10mm shower cable and a 2.5 immersion feed, she doesnt sla g me off saying ive charged him for doing nothing
I really did want to get to the bottom of it too but he just point blank refused and insisted on his old board
advised him he is living with big problems and it needs attention but its falling on deaf ears and his mrs who is just as old is more concerned that the cooker and kettle work now rather than the conditioning ofd the wiring
thanks god my name isnt on the cert
so I am quite releaved!!!!!

 

[JulianC]

Aww man, now we'll never know what the problem was. Get back down there and tell the old fella you won't leave until you've found the cause of the problem. No charge of course.

 

[lloyd1980]

I know!!!! I really wanted to know what was causing it!!! it had me intregued!!
I have stuff booked in now so am not going to sacrifice time off another paying job to look at a problem he doesnt care or isnt bothered about.
ive done more than enough work there that ive not charged him for to do more.

shame about not finding it tho I agree!!!!!

therell be another one next week somewhere, bloody DIY'ers

 

[bugsy]

At least you forfilled your reponsibilites as much as possible , why don't try and talk to his daughter explaining the possible dangers, might save calling out the fire brigade in 9 months time!

 

[uksel]

wouldn't have minded knowing the outcome of that bad boy

 

[MarcT]

Shame you can't get in there and check the N's on his meter. I'd reckon it to be the culprit. it caught me out once, i only found it 'cause my ear was right next to the meter.

 

[lloyd1980]

I know it is a shame
I checked the N's at the meter and they were ok
I went round to see his daughter last night with his reciept and a 3 page printed letter explaining everything
gave it to her and explained the lot, when I told her hed instructed me to stop work and to refit his old board and that the faults remained she groaned ohhhh nooooo with her head in her hands
she understood that id tried to do everything i possibly could to sort it out but hed stopped me and was going round today to speak to him,. I dont blame him he was just fed up with the constant tripping and wasnt prepared to pay for the time
I made sure on the invoice everything i did was listed and (FREE) marked next to the work hed not been charged for (there was lots!)
she asked how much to sort out and i advised I couldnt estimate and it would be time and materials but if they ever needed a cert for the flat, they wouldnt get one with the old board and the faults
told her if anyone fits the new board then the faults have to be sorted otherwise the rcd wont set
the ball is now in their court and Im happy ive done everything possible to help him
ultimatly tho it boils down to money that hes not prepared to pay
shame but thats how it goes!!

 

[Bobby B]

My money is on a low IR N - E fault on your ring final.
The more you load it (eg cooker/ microwave) the higher the current
will be that's bypassing the Rcd (parallel conductors) - It may only
be a tiny amount flowing via the cpc but it only has to be 20/25 mA
and...trip
The likes of the TV etc probably won't draw enough to do it.

That's my bet anyway - looks like you might be spending the day
splitting the ring[/QUO

yeah agree with that it's almost always N-E, I've had 3 or 4 that sound similar

 

[Marx]

I've 'solved' a similar tripping problem twice before when happening upon L-N polarity reversals in socket outlets.

 

[WayneL]

I've 'solved' a similar tripping problem twice before when happening upon L-N polarity reversals in socket outlets.

Wouldn't have thought that would trip an RCD