How to deal with RCD tripping - external noise

[springcrocus]

Last year I had a new rear-half exhaust fitted to the van. This year, it failed the MOT on the emmisions test. I suppose it must be the garages fault because they must have done something wrong.

Sign of the times, I'm afraid, it's always somebody elses fault. bad day explode

Actually, it turned out to be a faulty oxygen sensor (or something like that) which is mounted in the manifold and nothing to do with the exhaust.

 

[SPECIAL LOCATION]

1. My installation has had no significant tripping for the 7 or 8 years since my dis board was installed (i guess once or twice a year) - each time it was attributable to something internal, like once my dishwasher sump flooded the motor. Each time the RCD told me something was wrong, it got fixed and that was it. My installation has had no tripping at ANY OTHER TIMES - I can't say it more plainly - each time it trips, I check with the pub, and ALWAYS they have just turned their lights out.Please explain how an electricity supply can "show up the inadequacies of your installation"

I don't believe in a better supply showing up inadequacies - if I had RC issues, the RCD should have tell-taled it before - my supply runs 24/7 with no RCD trips - but it is now tripping since a "better" (lower-impedance) supply was installed - that just means I'm getting more noise into the dis board, and the RCD is acting upon it.

Sorry steptoe.... unless you can come up with a genuine scenario where the overlay can possibly cause RC faults, I'm not buying it.

2. Why should it cost me when I have enough evidence to say that what they have done is causing me nuisance tripping. They were the last people to do any work involving my supply, surely it is up to them to prove it is not there wrong-doings.

How much load are these lights actually drawing? < 9kW ?? :|

Why doesn't your RCD trip when another neighbour turns their electric show off? :C

If you have enough evidence...

Why are you asking on an internet forum???

just take them to court and claim the compensation you say you are owed!

Or...

Why not go to a hire shop and hire a monitor yourself to get you own readings?

From the information given so far I cannot see that you have 100% proven evidence.

How many final circuits on your CU.... ?

Any external supplies with their own local earth rods....garden sheds? Greenhouse? water features?

Have you had the RCD ramp tested?

:C

 

[daba]

I embed the answers in your questions

How much load are these lights actually drawing? < 9kW ?? :| Don't know : And I don't know if I can find out either

Why doesn't your RCD trip when another neighbour turns their electric show off? :C

I guess their loads are much smaller in comparison - none of my neighbours has a floodlit car-park, or a beer-garden.

If you have enough evidence...

Why are you asking on an internet forum???

just take them to court and claim the compensation you say you are owed!

I never said I was owed compensation - so far it has cost me nothing, except the nuisance of the power going off, all I want is the problem they have introduced rectified.

Or...Why not go to a hire shop and hire a monitor yourself to get you own readings?

Tried a search, and can't find anything - can you recommend a make/model, and where to hire from?

From the information given so far I cannot see that you have 100% proven evidence.

In my opinion, the circumstantial evidence is overwhelming

How many final circuits on your CU.... ?

4. Sockets House, Sockets Kitchen/Laundry, Lights, and Shower

Fridge/Freezer and Burglar Alarm are unprotected by the RCD

Pic of CU here : https://dl.dropbox.com/u/82993644/IMAG0028.jpg

Any external supplies with their own local earth rods....garden sheds? Greenhouse? water features?

No, the only earth rod is near to where the supply cable enters the building

Have you had the RCD ramp tested?

No, I want them to agree to pay for testing if it passes. Just gathering information while I await their response..

:C

 

[SPECIAL LOCATION]

I guess their loads are much smaller in comparison - none of my neighbours has a floodlit car-park, or a beer-garden.

How ,many lamps?

Gut feeling a leccy shower many be more power than the pub lighting....

You said there are two lighting circuits at the pub...

Which one do you think causes your RCD to trip?

Have you had the polarity checked at you house?

Cant see any stickers on that board saying when it was last tested?????

Have you got test certificates for it?

---------- Post Auto-Merged at 01:28 ---------- Previous post was made at 01:11 ----------

From the information given so far I cannot see that you have 100% proven evidence. In my opinion, the circumstantial evidence is overwhelming

How many final circuits on your CU.... ?

4. Sockets House, Sockets Kitchen/Laundry, Lights, and Shower

Fridge/Freezer and Burglar Alarm are unprotected by the RCD

Pic of CU here : https://dl.dropbox.com/u/82993644/IMAG0028.jpg

Poor design having a) only one light circuit & B) having those lights on the RCD side?

Why were the lights RCD'ed 7 years ago???????

In my opinion your "evidence" is rather underwhelming at the moment.

 

[daba]

Embedded responses

When was your installation last inspected and tested? BS7671 wiring regulations recommend a domestic dwelling is inspected every 10 years or at a change of ownership. Do you have up-to date test results? The CU was installed 6 to 7 years ago. I cannot find a test/inspection certificate, I don't even know if one was given at the time as I was working away when the work was done. Unfortunately I cannot ask my wife, as she is no longer with us.

Periodic inspection and testing would verify the condition of the cables and earthing within the property. All wiring, including yours deteriorates with age, RCD's do not always trip when something is switched on or off, e.g. moisture ingress into a poor joint or damaged cable can cause problems. Steve3948 gives a typical illustration in his post 9. The moisture content within the plaster walls or movement of floorboards, doors, putting something on a shelf are all none electrical related issues than can cause RCD's the trip. Are all the connections in your fuse box tight? Is your RCD over sensitive?

All of those types of "fault" or "condition" would occur at random times. I don't get any trips AT ANY other times. I can count on one hand the number of trips since the CU was installed, and all of those occurrencies were attributable to something. I thought I had a good case in proving the relationship between the RCD tripping and the pub lights being turned off - it seems many of you aren't as convinced as I am.

Does the installation have one global RCD or multiple RCD's installed? do they all trip or just one?

There is a central RCD : Essential circuits are unprotected. See my other post.

There is no reasonable reason why any supply company should have to test and prove these items in anyones home.if a homeowner has failed to follow the industry recognised testing and inspection periods themselves.

I agree with you in general - however, when the trip is being caused by an external influence, I don't see why I should have to pay. The DNO is duty-bound to provide a "clean" supply - and I don't believe they are in this case.

I am not saying your problem cannot be external, but you need to step back from your unproven ideas and go back through a systematical test of your own internal wiring first. As has been said earlier do you see any of your neighbours power tripping off at the same time as yours?

I have written a letter which I will distribute on the route of the new supply cable... the groundwork paint markings are still visible, and the fresh tarmac is easily followed.

Doc H.

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I guess their loads are much smaller in comparison - none of my neighbours has a floodlit car-park, or a beer-garden.How ,many lamps?

Gut feeling a leccy shower many be more power than the pub lighting....

You said there are two lighting circuits at the pub...

Which one do you think causes your RCD to trip?

Have you had the polarity checked at you house?

Cant see any stickers on that board saying when it was last tested?????

Have you got test certificates for it?

---------- Post Auto-Merged at 01:28 ---------- Previous post was made at 01:11 ----------

Poor design having a) only one light circuit & B) having those lights on the RCD side?

Why were the lights RCD'ed 7 years ago???????

In my opinion your "evidence" is rather underwhelming at the moment.

The CU was installed to replace the existing CU because I had the shower installed. That has since gone, and the shower circuit is unconnected.

The house was built in 1904, had gas lighting until the thirties, and has only one lighting feed from the then fuseboard. Same with the sockets, the whole house only has one ring-main. I had a separate ring-main feed added to the kitchen/laundry when that was updated 8 years ago.

I could ask them at the pub to turn their lights off in a specific order, with a minute between, but why should they be doing any testing for me. They'd have been on their feet since 10 am, and all they want to do is go to bed. They have been accommodating so far in writing down the time they switch them off. What I can say is that the landlady has noticed that the floodlight switches feel "funny" and resist being switched off, more so than any other circuits.

Could it be that the switches are arcing badly, and are starting to burn-out?

If I got a picture of the lights, would it be possible to identify them? Together with a count of how many there are, would it be possible to roughly calculate the load being disconnected?

Do you think I should recommend they get the brewery to inspect their installations?

Are you saying my CU lighting circuit should be unprotected by the RCD ? Is that the norm ?

Even if you are, that doesn't explain why the RCD only trips when the pub lights are turned off.

 

[steptoe]

OK,

if the DNO have actually upgraded you to a proper PME system then it is possible that some of your equipment may now be getting a better path back to earth,

therefore allowing more leakage current and tripping the RCD out, and this would happen right at the spike of when the supply is in reflex at the pub lights being turned off.

it could also possible be caused by a spike in the mains caused by the same, but less likely TBH.

you really have no alternative but to prove your own install is NOT at fault first, then, and only then can you go to the DNO, and you could also present the DNO with your bill too.

---------- Post Auto-Merged at 01:48 ---------- Previous post was made at 01:45 ----------

Embedded responses
---------- Post Auto-Merged at 01:43 ---------- Previous post was made at 01:32 ----------

The CU was installed to replace the existing CU because I had the shower installed. That has since gone, and the shower circuit is unconnected.

The house was built in 1904, had gas lighting until the thirties, and has only one lighting feed from the then fuseboard. Same with the sockets, the whole house only has one ring-main. I had a separate feed added to the kitchen/laundry when that was updated 8 years ago.

Are you saying the lighting circuit should be unprotected by the RCD ? Is that the norm ?

Even if you are, that doesn't explain why the RCD only trips when the pub lights are turned off.

if Im reading this right the house has not been rewired since the 1930's ?

and you want to blame the DNO for an RCD tripping out? headbang

 

[daba]

OK,if the DNO have actually upgraded you to a proper PME system then it is possible that some of your equipment may now be getting a better path back to earth,

therefore allowing more leakage current and tripping the RCD out, and this would happen right at the spike of when the supply is in reflex at the pub lights being turned off.

it could also possible be caused by a spike in the mains caused by the same, but less likely TBH.

you really have no alternative but to prove your own install is NOT at fault first, then, and only then can you go to the DNO, and you could also present the DNO with your bill too.

---------- Post Auto-Merged at 01:48 ---------- Previous post was made at 01:45 ----------

if Im reading this right the house has not been rewired since the 1930's ?

and you want to blame the DNO for an RCD tripping out? headbang

The house had been re-wired a year before we bought it, that would be about 20 years ago.

When did grey insulation come in?

"you really have no alternative but to prove your own install is NOT at fault first, then, and only then can you go to the DNO, and you could also present the DNO with your bill too"

Then that is probably the best I can do

 

[steptoe]

do you have proof of this?

20 years 'could' be seen as the installation nearing the end of its lifespan, depending on other influences most electrical installs are given a 25yr lifespan.

---------- Post Auto-Merged at 02:06 ---------- Previous post was made at 02:05 ----------

When did grey insulation come in?

are you sure it is grey insulation?

and not lead sheath.?

---------- Post Auto-Merged at 02:07 ---------- Previous post was made at 02:06 ----------

circa early '70s

 

[Steve3948]

About 28 years ago I had a client with the same problem, he spent about 6 weeks unplugging stuff for a couple days each time to try and locate the problem.

I had tested everything at least 3 times because he was convinced there was a problem with the wiring and each time it was a clean bill of health.

It always tripped around the same time 12:00am.

After 6 weeks he phoned me one morning to say he had found the culprit, it was his Beatamax video player going into standby sleep mode.

They only plugged it in to use it from then on and never had the problem again.

I must say I have never heard of an outside source tripping a Current RCD, the old Voltage type and rod yes, so this is a first for me, so I am interested in the outcome.

 

[lineman]

My two pence on this daba is that I didn't think a supply fault could trip an RCD. IMO this fault reeks of loose terminals on your RCD, or a fault on your installation. I would imagine the DNO will wash their hands of this unless you get a clean bill of health on your installation.

 

[daba]

Embedded responses

My two pence on this daba is that I didn't think a supply fault could trip an RCD. I have a technical document from the manufacturer that disproves the idea that the RCD will only react to the load side of it's terminals. That is what the DNO told me originally. Any discrepancies between L and N currents, for a specified time, will cause the device to trip. I don't know how it is happening, but it is definitely happening now because they have "upgraded" the buried cable.

IMO this fault reeks of loose terminals on your RCD, or a fault on your installation.

That does NOT explain why it only happens at the times of "lights-out" 150 metres away

I would imagine the DNO will wash their hands of this unless you get a clean bill of health on your installation.

Which is exactly what they are doing, so I am going to get an inspection done anyway. If it passes, I will ask then to pay the bill and then sort the problem out.

It happened again earlier, (at 10:37 to be precise), the RCD tripped yet again, and, as I have done for the previous 4 trips, (and with their permission), I phoned the pub to see if they had just turned their lights off. Guess what.......

Now I have to add that I have lived here for 20+ years, the pub has "lived" here for god knows how long, and it is only since the supply cable has been "upgraded" a couple months ago that the problem has started. Do we not get an impression that the CAUSE is external now?

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Where can I hire a reputable line condition monitoring device ??

Can't find anything suitable myself.

 

[SPECIAL LOCATION]

The CU was installed 6 to 7 years ago. I cannot find a test/inspection certificate, I don't even know if one was given at the time as I was working away when the work was done. Unfortunately I cannot ask my wife, as she is no longer with us.

For the work to have complied with BS7671 an electrical certificate should have been issued detailing all of the test results on your cables..

Without evidence that your wiring was up to standard or has been recently tested to confirm it is up to standards defined by BS7671..

you are pi55ing in the wind hoping to get the DNO to come and do something....

You have no written evidence that you polarity at your CU is correct...

You have no written evidence that your earthing arrangements are adequate...

You have no written evidence that the RCD is operating within correct tollerance...

You have no written evidence that your cables are electrically sound...

These are ALL you legal responsibilities..

no one else's just yours!!!

I am guessing you need to pay between

 

[daba]

I have said I will get it tested.....

Will they pay for the BS test if it passes?, because that will prove their supply is causing the problems.

Would you ask them to pay if it were your property affected by something outside of your tested, and passed, installation?

PS. what do you mean by "polarity"

PPS, they did a test of my "Z" (earth impedance). The engineer quoted the figure and then said "you can't get much better than that"

 

[sparky b]

I have said I will get it tested.....Will they pay for the BS test if it passes?, because that will prove their supply is causing the problems.

Would you ask them to pay if it were your property affected by something outside of your tested, and passed, installation? Yes

PS. what do you mean by "polarity" live/neutral the right way round

PPS, they did a test of my "Z" (earth impedance). The engineer quoted the figure and then said "you can't get much better than that" 'Z'what?, presuming Ze, if so, what figure??

My red...

 

[lineman]

Well then mate you know it all. Have dealt with many customers like you. You have argued every bit of (free) advice that sparkies have given you because it's not what you want to hear. Your "problem" has been solved twice over but you still milk free advice. What would you have done twenty years ago when there was no Internet?

 

[apprentice87]

Hi Daba,

I doubt very much that you will get the DNO to pay, even if your installation is tested and found to be perfect...

Reason 1,

They will merely say that the regs clearly state that you should have your installation tested at regular intervals anyway, and so why should they pay for something that is YOUR responsibility.

As i said, it is YOUR responsibility to have your installation tested and a current test certificate.

What you are doing, is a bit like telling the the local authority that they had to pay for the MOT on your car, because why should you pay, because they have not proved that the passage of their road under your car is not causing the wear....

Reason 2,

Even if you have you installation tested and it ok, this does not mean it is perfect.... They possibly could still say it is half "clapped out" as it were..

See it like this, when you take your car for an MOT, the brake pads may well be 90% worn out and it will still pass the test. This is not the same as saying that a brake pad with only 1.5mm of lining left is acceptable or in good condition. It is merely just about "roadworthy" at the time of the test.

They might say that your installation while not actually dangerous at the moment, requires improvement.... and that is down to you...

I think you will have to have a test [and pay for it] yourself, and just see this as a "distress purchase" much as going to the dentist or taxing you car is. As i said, the regs require that you have you installation tested anyway, so why SHOULD the DNO pay...

I think your best idea, [apart from asking the neigbours] is to get the supply monitor and see what happens. Next problem though, will be establishing what is a "satisfactory" supply. The only thing they HAVE to comply with [as far as i know] is to provide you with a voltage within tolerance, 230v +10% - 6% and the frequency has to be right, [or apparently it had to at one time] I have no idea how clean the supply has to be, all i can tell you is that, they can disconnect you if they find you are polluting their supply, but i am not sure if it works the other way about,,

Next thing, anyone know how anything about the duration of a "spike" far far less than the time it takes for an RCD to respond i would think. Not sure if turning off lights even could cause a spike, as a load of halogen lights would not be an inductive load anyway..

john...

 

[daba]

PPS, they did a test of my "Z" (earth impedance). The engineer quoted the figure and then said "you can't get much better than that" 'Z'what?, presuming Ze, if so, what figure??

0.14 is what he read out....

 

[daba]

embedded responses

Hi Daba,I doubt very much that you will get the DNO to pay, even if your installation is tested and found to be perfect...

Reason 1,

They will merely say that the regs clearly state that you should have your installation tested at regular intervals anyway, and so why should they pay for something that is YOUR responsibility.

As i said, it is YOUR responsibility to have your installation tested and a current test certificate.

and i will get the tests and certificates to prove my installation is sound

what you are doing, is a bit like telling the the local authority that they had to pay for the MOT on your car, because why should you pay, because they have not proved that the passage of their road under your car is not causing the wear....

irrelevant

Reason 2,

Even if you have you installation tested and it ok, this does not mean it is perfect.... They possibly could still say it is half "clapped out" as it were..

if it passes the tests, then it is deemed to be safe and usable. if the board trips due to an external disturbance it is their problem, not mine

See it like this, when you take your car for an MOT, the brake pads may well be 90% worn out and it will still pass the test. This is not the same as saying that a brake pad with only 1.5mm of lining left is acceptable or in good condition. It is merely just about "roadworthy" at the time of the test.

irrelevant

They might say that your installation while not actually dangerous at the moment, requires improvement.... and that is down to you...

who started talk about "dangerous" ffs, I have a problem introduced by a new supply cable, that's all - where did the idea that my house wiring is dangerous come into the discussion

I think you will have to have a test [and pay for it] yourself, and just see this as a "distress purchase" much as going to the dentist or taxing you car is. As i said, the regs require that you have you installation tested anyway, so why SHOULD the DNO pay...

I think your best idea, [apart from asking the neigbours] is to get the supply monitor no one has told me where to hire a suitable device from, even though asked and see what happens. Next problem though, will be establishing what is a "satisfactory" supply. IMO a satisfactory supply is one that doesn't cause tripping on a tested domestic installation using a commercially available RCD that meets all design standards and regulations The only thing they HAVE to comply with [as far as i know] is to provide you with a voltage within tolerance, 230v +10% - 6% and the frequency has to be right, [or apparently it had to at one time] I have no idea how clean the supply has to be, i argue it has to be as clean as it needs to be not to cause nuisance RCD tripping all i can tell you is that, they can disconnect you if they find you are polluting their supply, but i am not sure if it works the other way about,, wtf? : are you inferring I am polluting their supply?

Next thing, anyone know how anything about the duration of a "spike" far far less than the time it takes for an RCD to respond i would think. Not sure if turning off lights even could cause a spike, as a load of halogen lights would not be an inductive load anyway.. well neither am i unsure about that - perhaps our more enlightened members can explain how turning off some substantial load 150m down the line can cause an L-N imbalance strong, and long enough to cause my RCD to trip, because without a shadow of doubt, that is what is happening !

john...

 

[steptoe]

daba, not only will you need your installation tested, but everything you plug in will require a manufacturers certificate of compliance too, simply having a PA test on it in this circumstance I dont think is going to be sufficient.

 

[apprentice87]

Hi Daba,

If you really want to get to the bottom of all this, here is the man to do it; FaultLink International: Independent Fault Investigation & Analysis Specialists

No idea what it costs though, he can hire you a power quality meter or come and do it all for you. As i say, no idea what it costs...

Still, he does say this;

"Free Power Quality Consultancy" - not quite, but it's close! I cannot offer a legally binding verdict to the issue in question (unless you are prepared to pay, of course!), but I can offer a personal opinion based on the evidence presented.

If you want someone to stand up in court then you need a consultant/insultant (and the difference is not always based on how much cash you part with!). Apart from myself, I also have a small list of companies I could let you have (but please don't ask me to base my reputation on them!).

But, if all you are in desperate need of is a second point of view, then you are welcome to get in touch with me (please do so first as I block all large files being sent by email). Simply email via the link at the bottom of this page, and based on what is sent will then ask for files of your recordings.

Please note that I do not divulge any information to anyone. Your data is strictly private. The only part I may use as further content in this book is the problem itself and the findings offered. All names and places are removed before it is published and will run the pages past you before publishing, just to make sure you're happy"

Give them an email and see what they say!!!

Hope this helps..

Let us all know what they say...

john..