RCCB Tripping

[adam1984]

Afternoon all.

This is a weird one but I thought i would ask your thoughts to satisfy my own cuisosity and apologies for long post!

Board is a Crabtree with 1no RCCB. The RCCB tripped when the TV was plugged in and socket turned on. RCCB would not instantly re-set but it did after a couple of minute.

The RCCB supplied: Downstairs power, Upstairs Power, kitchen, Extension, utility/boiler (5mcbs)

So I reset RCCB. Go back to "TV Socket", plug in Martindale socket tester, switch on socket switch and RCCB trips (do this a couple more times and keeps tripping) The TV socket is on Downstairs power MCB.

Homewoner says that its normally the tumble dryer / kettle / microwave (on the utility MCB) that ususally trips the RCCB but once reset they work again.

Reset RCCB and and all MCB's are in the ON position. Go to utility room and plug Martindale socket tester into socket, switch on and RCCB trips again. I try several different sockets and trips every time however when the boiler is fired up it doe not trip the RCCB.

If I turn off the MCB to the Utility room and try my Martindale socket tester in the kitchen sockets then it trips the RCCB. If i turn off the the Extension and utility / boiler MCB then the "TV Socket" does not trip the RCCB and nieither do the kitchen sockets.

Now the extension is actually a 2 storey extension but when I turn this MCB off it only turns the power off to the downstair extension (granted the upstairs may have been taken off the upstairs power)

I took off every socket face on the affected circuits and wiring all looked fine. I checked all cables where possible (ones clipped direct etc) for signs of damage. I asked the homewoner if they have done any DIY recently. I checked all outside equipment for signs of water ingress or damage and everything I checked looked ok and no signs of damage.

The homeowner has lived in the house for approx 4 years and on the face of it it is really modern and had a massive refurb job done by the previous owners but the current homeowner has said they have had quite a lot of problems with te house and especially with the electrics.

I think that there is a dodgy conection somewhere but I couldnt find it so must be burried in / behind a wall somewhere.The junction boxes I found were wired ok. Anyone shed some light on what they think it may be? Ways in which you would try and trace fault? No insulation resistance test was carried out.

 

[TJ Anderson]

Also how would you go about ramp testing this particular RCD as it was a Crabtree star breaker RCCB with 2 neutral terminals on the face

Adjacent MCB Bottom Terminal and an Earth Terminal

 

[SPARTYKUS]

Also how would you go about ramp testing this particular RCD as it was a Crabtree star breaker RCCB with 2 neutral terminals on the face

...the same way you'd ramp test any other RCD......

 

[baldsparkies]

If your going to find the fault there is one major component you will need above all others.

​EXPERIENCE !

 

[R G]

Also how would you go about ramp testing this particular RCD as it was a Crabtree star breaker RCCB with 2 neutral terminals on the face

I don't believe this ..

 

[adam1984]

Here we go with the "I'm bigger and better than you" playground antics. I came here to ask advice / thoughts on what would be the way in which you would have dealt with this. Experience is what is required in this situation but how do I go about getting that? I didn't charge the customer, left them in a better situation then when I walked in the door and explained that they needed someone with the time and experience to deal with their situation.

 

[baldsparkies]

Please don't conduct an IR test.
It wouldn't be fair on the home owner.
You need to stop, ask an experienced electrician for there help, and learn from there actions.
I am not being unkind or un-helpful.
I am giving you sound advise before you either damage something, become very frustrated, or end up falling out with the home owner because they will eventually become suspicious of your lack of knowledge, and level of experience.
Your going for a stroll into the Amazon jungle, and you will get lost.

 

[Geordie Spark]

Afternoon all.

This is a weird one but I thought i would ask your thoughts to satisfy my own cuisosity and apologies for long post!

Board is a Crabtree with 1no RCCB. The RCCB tripped when the TV was plugged in and socket turned on. RCCB would not instantly re-set but it did after a couple of minute.

The RCCB supplied: Downstairs power, Upstairs Power, kitchen, Extension, utility/boiler (5mcbs)

So I reset RCCB. Go back to "TV Socket", plug in Martindale socket tester, switch on socket switch and RCCB trips (do this a couple more times and keeps tripping) The TV socket is on Downstairs power MCB.

Homewoner says that its normally the tumble dryer / kettle / microwave (on the utility MCB) that ususally trips the RCCB but once reset they work again.

Reset RCCB and and all MCB's are in the ON position. Go to utility room and plug Martindale socket tester into socket, switch on and RCCB trips again. I try several different sockets and trips every time however when the boiler is fired up it doe not trip the RCCB.

If I turn off the MCB to the Utility room and try my Martindale socket tester in the kitchen sockets then it trips the RCCB. If i turn off the the Extension and utility / boiler MCB then the "TV Socket" does not trip the RCCB and nieither do the kitchen sockets.

Now the extension is actually a 2 storey extension but when I turn this MCB off it only turns the power off to the downstair extension (granted the upstairs may have been taken off the upstairs power)

I took off every socket face on the affected circuits and wiring all looked fine. I checked all cables where possible (ones clipped direct etc) for signs of damage. I asked the homewoner if they have done any DIY recently. I checked all outside equipment for signs of water ingress or damage and everything I checked looked ok and no signs of damage.

The homeowner has lived in the house for approx 4 years and on the face of it it is really modern and had a massive refurb job done by the previous owners but the current homeowner has said they have had quite a lot of problems with te house and especially with the electrics.

I think that there is a dodgy conection somewhere but I couldnt find it so must be burried in / behind a wall somewhere.The junction boxes I found were wired ok. Anyone shed some light on what they think it may be? Ways in which you would try and trace fault? No insulation resistance test was carried out.

There's no gentle way to ask this son, but are you "sure" you know what you're doing there - Martindale Socket Tester an' all?? :uhoh2:

 

[Darkwood]

Hi Adam ... can you please update or fill out your profile so we know what level you are and then reply accordingly....

Lets assume you are a fully qualified Electrician out on a call with the issue in post 1 unless you correct us otherwise!

You should not go to a job like this and walk without even doing any basic tests, you have come on here asking what could be the problem and you have not followed any of the procedures you were trained to do. Walking away from a job with no idea what the problem is even if you are going back is not very professional, your customer would at least expect a report of your findings which would require testing - not sure what excuse you have used...

Reading throught the post it seems you are unsure of procedures, not fully understanding of earth fault leakage and unfamiliar on how to perform a ramp test.

-Your first step would be to identify the circuit tripping the rcd.
-Your second step would be to ensure all loads are disconnected and test the hardwiring.
-Depending on results of step 2 then either locate detected problem and rectify or reconnect circuit if tested ok and add the loads one at a time been aided by an earth leakage ammeter if you have one or until the device trips again.
-Ramp testing is an additional aid to finding high background leakage or designed earth currents to aid in identifying issues.

Asking how to perform a ramp test on any device is very worrying if you are qualified - your history shows you were in training of your 3rd year in 2012 so are we to assume you now are a practicing Electrician judging by following threads started by you - have you got no mentor or supervisor while you gain experience, yes agree we all have to go through a learning curve but you need to gain at leat 5yrs IMHO under someone elses wing to become a competent Electrician .... I'm hoping you not another one of the straight out of college to self Employment brigade who wing it and rely on forums to answer questions you really should know.

Apologise if I've second guessed your level wrong but we have to do this when you don't fill out your profile and start asking basic questions without even providing any testing data.

 

[Anthony S]

Experience is what is required in this situation but how do I go about getting that?

Work with Experienced Qualified Electricians, you ain't going to gain experience from a forum.

 

[baldsparkies]

Here we go with the "I'm bigger and better than you" playground antics. I came here to ask advice / thoughts on what would be the way in which you would have dealt with this. Experience is what is required in this situation but how do I go about getting that? I didn't charge the customer, left them in a better situation then when I walked in the door and explained that they needed someone with the time and experience to deal with their situation.

We crossed posts, but its a shame you didn't explain that you were aware of your lack of experience, and that you had already explained this to the customer.
The advice you have received is not because people are bigger or better.
Its because they know where you will end up.
And for that reason, take the advice as sound and good.

 

[Darkwood]

Here we go with the "I'm bigger and better than you" playground antics. I came here to ask advice / thoughts on what would be the way in which you would have dealt with this. Experience is what is required in this situation but how do I go about getting that? I didn't charge the customer, left them in a better situation then when I walked in the door and explained that they needed someone with the time and experience to deal with their situation.

I suggest you drop the attitude about the bigger better edge, its clear you have had little or no experience and are trying to form a career by side-stepping a crucial part of the path in working for a firm and using this time to be guided and gain the experience required...
Consider been this customer of yours, regardless of the no charge for your time, the impression you have given him is you are out of your depth and inexperienced. Don't get me wrong this is not a crime or anything to be ashamed of but you need to gain experience with a competent person before you go it alone ..... as is at present you will end up getting a bad name for yourself as customers do talk, chat txt FB and in the modern world its hard to keep a business successful if you keep having to walk away through inexperience.

Find a firm and do 2 - 5yrs to get a grasp of your trade and make sure you have a good mentor and not a company who have little interest in educating you, plus be wary of contract agreements you may be subject to limitations on leaving and setting up again for a few yrs if your target customers is the same as the firm you work for.... this is a normal agreement to protect the business interests of the company who give you that experience.

 

[adam1984]

Thank you all for taking the time to reply to me even if some of the posts have got my back up but yes my lack of experience is evident and I take on board the comments.

I haven't come up against a fault like this before and obviously approached it in completely the wrong way. I wasn't using the socket tester to try and show / solve the issue but that has obviously came across in my original post.

Being out off college for sometime now and not working in the industry full time leaves me really nowhere to turn other than forums to pick up advice, wrong doings etc.

The sequence off events that seemed to trip the RCD is what completely baffled me.
Had the fault been local to one circuit, say for instance the utility room circuit, and it was this circuit that was tripping the RCD I would have felt much more comfortable trying to solve it. The fact that every socket on various circuits were tripping the RCD really threw me hence me advising that an better experienced Electrician should take a look.

 

[baldsparkies]

That's why you need someone to cover a methodical fault find procedure isolating all related circuits completely from the board.
Ramp testing the Rcd and IR testing each circuit with no loads connected.
When your experienced sparky arrives try to spend some time with him, you will gain that way a lot more than on a forum.

 

[Deleted member 9648]

That's why you need someone to cover a methodical fault find procedure isolating all related circuits completely from the board.
Ramp testing the Rcd and IR testing each circuit with no loads connected.
When your experienced sparky arrives try to spend some time with him, you will gain that way a lot more than on a forum.

When fault finding I'd leave loads connected with the exception of highly vunerable equipment like computers.You are looking for a low reading,which is just as likely on connected equipment as on the circuit itself. You want to verify the system as it will be used.As long as you dont do a L-N test...(pointless as far as RCD tripping is concerned)..and if in doubt start with a soft test at 250v there is no risk of damage and more chance of tracing the source of the fault.

To the OP.
RCD tripping is nearly always down to a low IR on either a circuit or connected equipment.Test as above as the first course of action. It constantly amazes me how many of these threads are all about ramp testing etc with no mention of the real cause in 99% of cases....Low IR to earth. Why is it that people seem to assume the RCD is faulty before considering the most likely reason?
I do RCD fault finding with monotonous regularity,and it's rare that I have to get the ramp tester out.....all that is required in nearly all cases is an IR tester. This is backed up by the vast number of times I've attended jobs wher other electricians have replaced 'faulty' RCD's and yet the random tripping continues. If they'd got their IR tester out they'd have found the real cause and saved the client the cost of an unecessary RCD.

 

[Plonker 3]

The reason we ask for ramp test or RCD timed test is it is a simple 5 minute that immediatly proves weather it is faulty or not. I know I always test it before anything else as a matter of course.