Earth fault

[luem]

I have a house on an estate of 8 houses in Cyprus. The houses are modern and the electrics a good standard. The electricity to the houses is supplied alternately on 2 of the phases, the 3rd phase being reserved for street lighting. Each house has a box outside in which is the meter, 80amp fuse and a 63 amp DP isolator switch. Inside the house is a consumer unit housing the MCBs and a 63 amp RCCD (all Hager). My RCCD trips out for no apparent reason, at random times. The wiring from the CU onwards has been checked and there is no earth fault. I think the cause is an earth fault in one of the houses on the same phase. Could this be so? (I'm not an electrician!!) If it is, could I safely replace the RCCD with a 63 amp DP isolator switch? I have one outside socket and that is in an IP56 enclosure with an RCCD built in.

 

[Penance]

More likely a faulty unit.

 

[BOROROBBO]

i wouldnt think another houses fault would trip your RCD.

when you/whoever checked the wiring im guessing you did a quick RCD test to see what it brought up?

what appliances do you have plugged in when it trips? try taking all appliances out and seeing if it trips over the course of a few hours or day or whatever

 

[luem]

Thanks for the replies.

Penance - what do you mean by faulty unit?

BoroRobbo - The trips can occur anytime, twice in 15 minutes, then days before the next!!

When the sparks were working on the next house but one, trying to locate a fault, mine tripped out about 3 times while they were working.

 

[luem]

BoroRobbo - forgot to say, an electrician tested mine. Unplugged everything then used something like a Megger to test all the circuits.

 

[MarkieSparkie]

luem, You would be best advised to get your electrician to perform 1) A leakage test of the earthing system of your installation and then the external supply with your installation isolated. 2) A ramp-test on your RCCB to measure the current at which it actually trips. From this information he/she should be able to determine the cause of the tripping and take remedial action.

 

[pushrod]

I would suggest keeping a log of what appliances were switched on everytime the rcd trips. It could well be that several appliances have sub-threshold earth leakage currents that cumulatively can trip the rcd. Also the rcd needs to to be properly tested at 0.5x, 1x and 5x In (30mA). Also i would get the rcd ramp tested to find what current is making it trip.

If you remove your rcd you are making your installation less safe. Better to persevere, find the problem and get it fixed.


Edit ; apologies for the repetition of your answer Markie - it wasn't there when i started writing lol

 

[BOROROBBO]

BoroRobbo - forgot to say, an electrician tested mine. Unplugged everything then used something like a Megger to test all the circuits.

as long as he did the tests described my markiesparkie and pushrod he should be close to determining the cause of the fault.

i know what your saying about next door when they had work being done but maybe that was coincidence... try unplugging all appliances and only using the bare minimum and keep a note of what was plugged in when it tripped

 

[Engineer54]

I have a house on an estate of 8 houses in Cyprus. The houses are modern and the electrics a good standard. The electricity to the houses is supplied alternately on 2 of the phases, the 3rd phase being reserved for street lighting. Each house has a box outside in which is the meter, 80amp fuse and a 63 amp DP isolator switch. Inside the house is a consumer unit housing the MCBs and a 63 amp RCCD (all Hager). My RCCD trips out for no apparent reason, at random times. The wiring from the CU onwards has been checked and there is no earth fault. I think the cause is an earth fault in one of the houses on the same phase. Could this be so? (I'm not an electrician!!) If it is, could I safely replace the RCCD with a 63 amp DP isolator switch? I have one outside socket and that is in an IP56 enclosure with an RCCD built in.

I'm afraid that very few house electrical installations in Cyprus are to a ''Good Standard!!!'' The installation will be a TT system, the RCD device will be rated at 500mA.... If what your saying about the supply arrangement is correct, and i don't think it is, ...that would be a huge unbalance. Most of the houses/villas are supplied via overhead distribution, 5 Lines (from top to bottom you have L1, L2, L3, Street lighting Live, N.) The neutral tends to be a reduced neutral...

Where abouts are you in Cyprus?? ...If your not that too far away, i might be able to pop round and have a look

 

[luem]

Engineer 54

Thanks for the reply. The electricity supply is by underground cables from a new substation approx. 40 yds away. It only supplies our site. The RCCD is rated at 300mA. I'm only assuming alternate houses are on the same phase because when the workmen were tracing the fault at no. 24, the RCCD tripped at my house (no. 28) and at no.32 at the same time. The houses are even nod. on our side. Unfortunately Engineer 54, my house is in TRNC.

The problem with unplugging all appliances is that it can and often does go days before tripping even with all aplliances connected.

 

[Engineer54]

Can't say in that case, as the supply systems are going to be different. From what i hear from past European/Brit residents of the TRNS, the new house electrics are even worse than this side ...lol!!!

Is your house roded (has an earth rod)?? If not, where does the green and yellow earth wire originate from, the main supply cutout/fuse, or from the cables Steel Wire Armours earthing?? Under normal circumstances, what your describing should not happen, as RCD devices only see downstream from where they are connected in the installation, they can't see faults on the supplying lines.

My only advice to you in this situation, is basically to try and find a good Brit or European electrician to come and have a look at your set-up. Only through competent testing, will an answer be found as to what is causing your problem and hopefully a resolution....

 

[luem]

Thanks Engineer,

I'm in UK at the moment. I don't recall seeing an earth lead in the meter box, so probably an earth rod. Do you know of a good spark on our side?

 

[Engineer54]

Another thought, ....You could do away with your 300mA RCD device, and replace your MCBs with 30mA RCBOs of the same rating as the MCBs being replaced. This can be a little expensive, depends on how many breakers you have in your CU. They will make your installation far more secure, as only the circuit that has a fault will trip, NOT the whole installation as you have right now... Here i can buy them at around 9 Euros a piece. Worth thinking about and a good investment in the short and long term...

 

[Engineer54]

Sorry i don't know of any on your side of the Island. I'm not here most of the time, and will be going off again around the end of the month ... just packing things up now!! ..lol!!!

 

[i=p/u]

testing the leakage on your earth system, what instrument would you use again as i forget, im thinking clampmeter but i reckon the range on this isnt low enough??? just a quickie

luem, You would be best advised to get your electrician to perform 1) A leakage test of the earthing system of your installation and then the external supply with your installation isolated. 2) A ramp-test on your RCCB to measure the current at which it actually trips. From this information he/she should be able to determine the cause of the tripping and take remedial action.

 

[pushrod]

Thanks Engineer,

I'm in UK at the moment. I don't recall seeing an earth lead in the meter box, so probably an earth rod. Do you know of a good spark on our side?

Just out of interest where are you in the TRNC - i usually spend a couple of weeks in Yesiltepe (towards Alsancak) in the summer - mind i don't pack all my tools

 

[oldtimer]

You are doing the right thing disconnecting your appliainces one thing to highlight though the appliances that can cause it is washing machines, dishwashers etc but one thing you did not mention was do you have a pool and if so the pumps that feeds it could have problems so if this is the case swith the pump off for a day and if no trips then Dos San Maguels Porv vavor or is that in another coumtry then !!

Mind you my other half has always wanted to go to cyprus I wonder if customs will let me take my trusty 1553 ?

 

[luem]

Another thought, ....You could do away with your 300mA RCD device, and replace your MCBs with 30mA RCBOs of the same rating as the MCBs being replaced. This can be a little expensive, depends on how many breakers you have in your CU. They will make your installation far more secure, as only the circuit that has a fault will trip, NOT the whole installation as you have right now... Here i can buy them at around 9 Euros a piece. Worth thinking about and a good investment in the short and long term...

Thanks for that, you're really helpful. I was thinking along the same lines ie. RCBO. It's a 10 way, ranging from 6, 16 and 32 amp. If I put RCBOs on, could I replace the RCCD with a 63 amp DP isolator. Where can I get them in the South for 9 euros? Will they fit on the Hager Din rail?

 

[luem]

Just out of interest where are you in the TRNC - i usually spend a couple of weeks in Yesiltepe (towards Alsancak) in the summer - mind i don't pack all my tools

Thanks Pushrod. My house is in Karsiyaka, just along the road. I'm out on 4 May for 2 months

 

[luem]

You are doing the right thing disconnecting your appliainces one thing to highlight though the appliances that can cause it is washing machines, dishwashers etc but one thing you did not mention was do you have a pool and if so the pumps that feeds it could have problems so if this is the case swith the pump off for a day and if no trips then Dos San Maguels Porv vavor or is that in another coumtry then !!

Mind you my other half has always wanted to go to cyprus I wonder if customs will let me take my trusty 1553 ?[/QUOTE ]

Thanks Oldtimer. I do have a pool, on its own circuit 32amp MCB in CU. The spark went into the pool room to test the pump but he didn't check anything in the cabinet in the pool room ie. contactor, timer etc. The problem is I have an outside pump for the water supply, a well pump (submersible in the well) and a pump for the garden irigation system. These are all spurred off the 32 amp ring main. I suppose RCBOs is the best route as otherwise "needle in haystack" springs to mind!!

 

[luem]

I just want to say this to everyone - I've only just joined this forum and I am absolutely amazed at the helpful replies you have all posted. It is indeed very refreshing and reassuring to find such caring people.
Thank you all!!

 

[Engineer54]

Thanks for that, you're really helpful. I was thinking along the same lines ie. RCBO. It's a 10 way, ranging from 6, 16 and 32 amp. If I put RCBOs on, could I replace the RCCD with a 63 amp DP isolator. Where can I get them in the South for 9 euros? Will they fit on the Hager Din rail?

Yes Luem, that is exactly what you would do when removing the RCCD. As far as i am aware , all MCBS/RCBOs are Din Rail fitted. I'm not aware either, that, Din Rails sizes in CU/DB's are any different from one manufacturer to another!! You can purchase the RCBOs at around this price in most of the so-called wholesalers....

 

[luem]

Yes Luem, that is exactly what you would do when removing the RCCD. As far as i am aware , all MCBS/RCBOs are Din Rail fitted. I'm not aware either, that, Din Rails sizes in CU/DB's are any different from one manufacturer to another!! You can purchase the RCBOs at around this price in most of the so-called wholesalers....

Can you give me the address or phone nos of wholesalers in the south?

Also I got my figure wrong earlier. I said 300mA, but shouldn't it be 30mA?

 

[Engineer54]

Deep submersible Well pumps are notorious for supply cord problems. When these pumps kick in, the cords can, and quite often are dragged against the well bore sides, eventually wearing the sheath and insulation down to the conductor cores. Every so often get a neighbour to give you a hand to pull the pump up from the well in order for you to inspect the motor supply cord for any damage. If caught in time, amalgamating electrical tape can effect a lasting repair, if damage has not penetrated the conductors insulation....

 

[pushrod]

Hey luem is it just one rcd protecting all 10 mcbs? The 63A rating on the rcd is the max current it can safely take. I have come across boards where you add up the mcbs and you get something like a theoretical max of 160+Amps all being protected by one 63A rcd. Now in reality you don't get that max current but it can be enough current to cook the rcd so that it becomes a bit random. Swapping a new one in fixed it. Mind when i have done it i tested the rcd and knew it was that before changing it. However, for about £20 you can get a replacement and swap it over and you might just be lucky and have sorted it - if it doesn't you have a spare. If you do try this be very careful about safe isolation first.

BTW i do vaguely know Karsiyaka, been through it a couple of times when coming down from the end of the mountain top road where the ruined tank is or from Kozan? - looked nice.

 

[pushrod]

Can you give me the address or phone nos of wholesalers in the south?

Also I got my figure wrong earlier. I said 300mA, but shouldn't it be 30mA?

yep should be 30mA.

 

[luem]

Deep submersible Well pumps are notorious for supply cord problems. When these pumps kick in, the cords can, and quite often are dragged against the well bore sides, eventually wearing the sheath and insulation down to the conductor cores. Every so often get a neighbour to give you a hand to pull the pump up from the well in order for you to inspect the motor supply cord for any damage. If caught in time, amalgamating electrical tape can effect a lasting repair, if damage has not penetrated the conductors insulation....

Thanks for that, good advice

 

[luem]

Thanks for that Pushrod. I had heard that the RCD can get flaky. How could I test it to find out.

You're right about Karsiyaka; we're on the seaside of the main road.

 

[Engineer54]

Can you give me the address or phone nos of wholesalers in the south?

Also I got my figure wrong earlier. I said 300mA, but shouldn't it be 30mA?

I don't normally call these wholesalers i just go in person, ....most make out the can't speak English on the phone , but strangely can when you turn up there ..... and can see your money!!! lol!!!

Depends, i had a 500mA front end RCCD originally, Now all changed to RCBOs. Seen a few 300mA over here too, but never a front end 30mA .... I would say 99% of all houses and villas here, have a 500mA front ender. Check when you back in May as to the exact value of your device. As i say, no matter what, you are going to be far better off converting your 10 way CU, ...Front enders are, ...and always have been a real pain in the rear!!! ..lol!!!

 

[luem]

I don't normally call these wholesalers i just go in person, ....most make out the can't speak English on the phone , but strangely can when you turn up there ..... and can see your money!!! lol!!!

Depends, i had a 500mA front end RCCD originally, Now all changed to RCBOs. Seen a few 300mA over here too, but never a front end 30mA .... I would say 99% of all houses and villas here, have a 500mA front ender. Check when you back in May as to the exact value of your device. As i say, no matter what, you are going to be far better off converting your 10 way CU, ...Front enders are, ...and always have been a real pain in the rear!!! ..lol!!!

What's a front ender? and shouldn't they be 30mA? What do you mean by value of device? Remeber I'm not a spark, just a thick lawyer!!!
Just realized what you mean - yes I think the RCCD is rated at 300 milliamp, it's a Hager

 

[pushrod]

Thanks for that Pushrod. I had heard that the RCD can get flaky. How could I test it to find out.

You're right about Karsiyaka; we're on the seaside of the main road.

really need an rcd tester that is going to set you back a lot of cash - my multi tester cost me about £650 - they're not cheap! BTW should have said earlier if you do want to just try the swap a 30mA, 80A rcd will be more robust than the 63A version and will probs cost an extra £10.

 

[luem]

really need an rcd tester that is going to set you back a lot of cash - my multi tester cost me about £650 - they're not cheap! BTW should have said earlier if you do want to just try the swap a 30mA, 80A rcd will be more robust than the 63A version and will probs cost an extra £10.

.

Thanks I'll try that. I am right aren't I - it should be 30mA and not 300 milliamps?

 

[pushrod]

What's a front ender? and shouldn't they be 30mA? What do you mean by value of device? Remeber I'm not a spark, just a thick lawyer!!!
Just realized what you mean - yes I think the RCCD is rated at 300 milliamp, it's a Hager

The place we stay at is a new build (about 6 years old) and it has an ordinary 30mA Hager rcd in, with most of the mcbs protected by the single rcd - wouldn't be surprised if yours is the same, especially if it is under the same plastic cover as the mcbs . If you have anyone out there who can check for you it would certainly be useful.

 

[Engineer54]

I hope your not so thick a lawyer, to have purchased a property on disputed land?? hahaha!!!

I would make the effort to employ a good electrician, to undertake any testing of your installation, and for him to convert your CU/DB. How long have you had your house?? Is it still under any form of warranty, ....or is that a rather silly question?? Get that electrician to give you a report on your properties electrical installation, if it's very bad, you maybe able to get the developer to pay for the RCBOs (he said ...tongue in cheek!!! lol!!) Also check if RCBOs are not as cheap in your neck of the woods as they are in mine, they may even be cheaper over there ....lol!!!

 

[luem]

The place we stay at is a new build (about 6 years old) and it has an ordinary 30mA Hager rcd in, with most of the mcbs protected by the single rcd - wouldn't be surprised if yours is the same, especially if it is under the same plastic cover as the mcbs . If you have anyone out there who can check for you it would certainly be useful.

Sounds exactly the same! 6 years old 10 way non split Hager CU, hager MCBs and RCD

 

[luem]

I hope your not so thick a lawyer, to have purchased a property on disputed land?? hahaha!!!

I would make the effort to employ a good electrician, to undertake any testing of your installation, and for him to convert your CU/DB. How long have you had your house?? Is it still under any form of warranty, ....or is that a rather silly question?? Get that electrician to give you a report on your properties electrical installation, if it's very bad, you maybe able to get the developer to pay for the RCBOs (he said ...tongue in cheek!!! lol!!) Also check if RCBOs are not as cheap in your neck of the woods as they are in mine, they may even be cheaper over there ....lol!!!

Disputed Land?! Round Larnaca and Limassol maybe, but not here!!! RCBOs in UK lot more expensive, and even more in TRNC

 

[pushrod]

I hope your not so thick a lawyer, to have purchased a property on disputed land?? hahaha!!!

I would make the effort to employ a good electrician, to undertake any testing of your installation, and for him to convert your CU/DB. How long have you had your house?? Is it still under any form of warranty, ....or is that a rather silly question?? Get that electrician to give you a report on your properties electrical installation, if it's very bad, you maybe able to get the developer to pay for the RCBOs (he said ...tongue in cheek!!! lol!!) Also check if RCBOs are not as cheap in your neck of the woods as they are in mine, they may even be cheaper over there ....lol!!!

TBH engineer i've seen quite a few new builds on the turkish side and the standards are fine - most with 16th rather than 17th edition boards, mind that is hardly surprising - it is the old property that is scary.

 

[Engineer54]

TBH engineer i've seen quite a few new builds on the turkish side and the standards are fine - most with 16th rather than 17th edition boards, mind that is hardly surprising - it is the old property that is scary.

I know what you mean, but the Cyp's will always make things look nice on the surface, it's only when you start digging around deeper, that the anomalies start appearing!!!....lol!!!

The old properties are much easier to see what's lurking, ....electrically speaking, nowhere to hide the cock-ups!!! I'd be more worried about the place falling down on my head ...lol!!!

 

[MarkieSparkie]

testing the leakage on your earth system, what instrument would you use again as i forget, im thinking clampmeter but i reckon the range on this isnt low enough??? just a quickie

A special type of clamp meter i=p/u, it has very sensitive mA current ranges, typically at 0.01mA resolution and usually has additional filtering to reduce the effect of harmonics/noise from the measured value, as well as a maximum value hold switch.

 

[Knobhead]

Remeber I'm not a spark, just a thick lawyer!!!

Thank god I didn’t give any advice… Sorry

 

[luem]

Thank god I didn’t give any advice… Sorry

lol. I retired years ago!!