Fault on RCD Trip

[ADS]

PME IS N&E on one rod.do you actually understand how earthing works?

comments like this are what make me reluctant to answer such questions.

and some people may wonder why there was so many replies before I commented.

sorry, but this sort of thing is why I have decided to sit back much more.

We know all this, but the neutral isn't connected to earth on the consumer side so current from two doors down isn't going to come flowing up your incomming neutral, through your RCD and along the neutral of one of your final circuits - thus causing an imballance and tripping the RCD - it's not going to happen.

An imballance in his RCD has nothing to do with the earthing system, so you are wrong - admit it.

Please don't start your petty slanging now, just to divert from the discussion - if you still think you are right, then explain how it would happen.

 

[NozSpark]

TBH I don't fully understand this, but I have experienced it.

I had a customer who's RCD was tripping out regular and for no apparent reason.. after carrying out IR checks on the installation I found that 1 particular circuit was breaking down to earth (the wall!) so I fixed that, but the RCD was still tripping from time to time and whenever I tested all my results came back fine!

About a week later I was passing the property and saw that the DNO were digging up the road a couple of doors down, after that (what they did I do not know) the RCD tripping fault disappeared.

My guess would be that they had a O/C or high N resistance in the network, possibly supplying a house on a different phase and that this property was picking up that out of phase N voltage on it's PME earth????

 

[a1]

Calm it down Please Gents.

 

[paul b b]

 

[kenwood33]

To answer a few questions. My neighbour has the same RCD as we all do. Our house was built in a row of 4, 4 years ago. Our neighbours trip does not go when they use their lawn mower/strimmer. He takes his supply from the house not the garage. Our other 2 neighbours do not have a problem when he mows/strims only us. Everytime he does these jobs our electric goes off without fail, thats the only time our electric trips and yes it is frustrating if not a puzzle, especially when the original elctricians that installed the electrics in all 4 properties say that this is not possible for our neighbour to affect our board!! we know it is but proving it is another matter.

The electrician when he came told us that we must go back to basics and test every socket in the house (a qualified electrician that is) however, he would not be willing to do this at any cost or price of money.

Thanks for everyones input it is most appreciated. We would prove it if he let us but he didn't want to know.

 

[Lee321]

get the dno out

 

[AndyD1]

If your house is in a terrace and built at the same time it may be worth isolating your DB and checking with your neighbour that the socket he uses to plug in the strimmer stays on!

I have seen this before on new build where the circuits from different house are crossed when they are wired i.e. ring final circuit taken through the wall from house 1 to house 2 and visa versa

 

[steptoe]

what happens is possibly similar to what Nozspark said,

so for this scenario ATM we will use that.

high resistance path to N on mower mans house, so the N current goes down the earth rod(PME), this current is then picked up by fault mans house(RODDED PME) as it is easier for the current to flow through copper than soil,

this current then flows through the Neutral cable IN BOTH DIRECTIONS, cables are NOT one way systems, this current hits the back end of fault mans RCD causing an imbalance so it trips.

quite why it only happens when mower man is cutting the lawn Im not sure, poorly insulated ext lead on the grass(?) or something similar perhaps.

maybe a Ze and PFC on both houses woul;d help to prove/disprove this idea,

but in all honesty, without being there to do some tests I can only go on past experience and how earthing in general works.

I think this is deffo a problem that cant be fixed by thought alone.

 

[Megaohm7]

It's certainly brought about some keen replies from the guys . It's good having to use the grey matter once in a while on trying to find an answer to your problem Guinness

 

[Sidewinder]

To start OT I spoke to KME earlier about his pub "issue".

I said I'd have a look through the GN's tonight for some enlightenment, I have all 8, as I have, to for various reasons we won

 

[steptoe]

To start OT I spoke to KME earlier about his pub "issue".I said I'd have a look through the GN's tonight for some enlightenment, I have all 8, as I have, to for various reasons we won

 

[green-hornet]

Its just amazing to watch when so often you are proved right IMO.

Never mind, you tell sidewinder what you mean and he will translate for usROTFWLROTFWL

 

[Sidewinder]

Shall I continue later? :innocent

Did I tell you i do teach as well as work!!! :Blushing

Paul

 

[steptoe]

Its just amazing to watch when so often you are proved right IMO.Never mind, you tell sidewinder what you mean and he will translate for usROTFWLROTFWL

this is getting ridiculous, its almost as bad at work sometimes when I get frustrated then I start talking fast and dropping into my local lingo and on occasion someone has to translate for me then too.!!! headbang

but like I said, its not about being proved right or wrong, its about learning and understanding.

Shall I continue later? :innocent Did I tell you i do teach as well as work!!! :Blushing

Paul

and it seems as though you teach very well indeed Mr Winder.

you crack on as you see fit.

 

[Sidewinder]

So to recap, at this stage we have a current carrying conductor, CNE which has a volt drop between the consumers DNO head and the PME

 

[Theorysparky]

Ok i put my hands up i dont know why this is happening but...what about RF interference caused by the strimmer ??????

you could borrow the strimmer and plug it in to one of your sockets ???

I will delete this then !!!!! :innocent

as Steps and Sidewinder have explained the cause perfectly

 

[steptoe]

So to recap, at this stage we have a current carrying conductor, CNE which has a volt drop between the consumers DNO head and the PME

 

[Sidewinder]

Course you can steps.

Its a BSc. (Hons) in Engineering & an MEng to follow with an ongoing smattering of vocational training, preceded by an apprenticeship, & HNC, followed by a NEBOSH General Certificate, before and after this were various C&G's including 16th, 17th, 2391 & 2400!

They are all in lever arch files on shelves in my office please let me know when you would like to come down to Swansea for them!

:^O

:coat

 

[sparkytim]

So then whats the situation here that relates to RCD tripping?

And what can be done?

 

[steptoe]

Course you can steps.Its a BSc. (Hons) in Engineering & an MEng to follow with an ongoing smattering of vocational training, preceded by an apprenticeship, & HNC, followed by a NEBOSH General Certificate, before and after this were various C&G's including 16th, 17th, 2391 & 2400!

They are all in lever arch files on shelves in my office please let me know when you would like to come down to Swansea for them!

:^O

:coat

you have all that, and you seriously think I may be on the right path about this fault?