rcd tripping

[davek]

Hi all
Just done a EICR on a property no majors findings, then owner who is rentingthe property out say the rcd is tripping, my first thought is it something Ihave done, turns out it has beenhappening for a long time.

Thecircuits that are on the rcd are cooker which was switched off at dp switch,shower which was switch off at dp switch and washing machine plugged in andfridge which they say is quite new but it did it before that, tested rcd triptimes and a ramp test but seem reluctant to rest first time. Any thoughts. Thehouse is empty at the moment no signs of a any diy wiring on sockets etc

 

[trev]

First off, there's there's no pass or fail on an EICR. It's either satisfactory or unsatisfactory with the reasons stated on the report, referenced to the regs.
Now, you limited a circuit or several because you knew they would "fail" but left them connected?
If the place is empty why was there a need for any limitations?
Why are you testing hard wiring with appliances still connected?

 

[Plonker 3]

What were your IR results? R1+R2 results?

Is every item of current using equipment disconnected and its still tripping?

 

[HappyHippyDad]

Davek, could you rewrite your post without all the spelling mistakes and ask a direct question as I'm a bit too tired to unravel it? Not meant to be rude just speaking factually.

Heres some advice I keep on file if it is simply the tripping RCD you are asking advice on:

Re: RCD tripping
Tryand diagnose the fault first.
When does it trip? Is it atthe same time each day, was anything specific on at the time?
Does the RCD reset at once ordo you need to turn off breakers first?
Remember it could be anappliance fault and not just the fixed wiring (which is normally fairly stable)
Intermittent faults are anuisance to find.
Permanent ones should be quick(N-E fault if it doesnt clear on switching off breaker or L-E fault if itdoes).

Similar times are for timedthings like heating controls, random times with no one at home is automaticthings like fridges and freezers. When someone is home were they turning onanything at the time or walking anywhere in particular that may have a damagedcable under it.
Which circuits are tripping?
Has there been any work doneof any kind DIY or professional?

This should allow you tonarrow things down slightly, with luck and then you should assess the affectedcircuits for obvious faults, loose damaged accessories, outside lights full ofrain?

Then test RCD.
Then see if you can recreate thefault if at all possible so that you can then switch off breakers to narrowdown to the circuit (if L-E) or remove neutrals (if N-E).

L+N to E may well allow you toidentify the specific circuit and then it gets fun as you remove all loads andtest L-E and N-E and start to break the circuit down to narrow the fault to apoint or junction box.

Could be quick could be slowbut good practice.
ThanksBlog this Post

Thanked 417 Times in 341Posts
Re: RCD tripping
Good advice from Richard,
The only way I differ fromthe majority on here is that when I have a tripping RCD...intermittent orotherwise... my first step is always a global IR test on thefixed wiring......I’ve had many occasions when other electricians have ‘cured’the fault by relacing RCD’s after apparently unsatisfactory ramp tests....ordisconnecting suspect appliances etc etc,only for the fault to continue afterthey’ve left,usually a fault on the fixed wiring shows up and would have doneall along if they’d bothered to test. Eliminate that first before lookingelsewhere.


PS.. apologies for some joined together words, this seems to be happening with 'copy/paste' at the moment!!

 

[davek]

Hi dillb
not tried that yet, customer never mentioned the trip problem, the garage as a DIY disaster, so was not going waste, time and money. Its now been refitted with ip rated box and ring plus lights the garage is now nota an issues basically it was a unsatisfactory. I monitored It through out the day fridge cutting In and out with no trip issues that is the only thing running. but seems this problem has been there or a few years. tempted replace rcd if I can find one it is a G E T board will dig results out in the morning as bit late and in van.

 

[Plonker 3]

Why replace the RCD? You have already said it passed ramp test and relevant tripping time tests.

 

[Octopus]

This thread needs facts and figures!

 

[Guest77]

Hi all
Just done a ecir on a property no majors past fine, then owner who is renting the out say the rcd is tripping, first thought is i tsomehing I have done turns out been happening for a long time. had to rewire garage as I lim due to it would just have failed, crcuits supllied on rcd are cooker switched of at dp switch, shower the same and washing machine plugged in and fridge which thy say is quite new bu did it before that, tested rcd trip times and a ramp test but ssaeem reluctant to rest first time. any thoughts. the house is empty at the moment no signs of a any diy wiring on sockets etc

Please write this post again in English with some more information.

 

[davek]

hi
here are the circuit and results on the RCD side.
sockets r1=0.19 rn=0.19 r2= 0.36 IR L-N/E =225Mohms ZS=0.40ohms rcd trip time 1n 18.4 5n7.4ms

cooker r1+r2 =0.06 IR L/N.>500Mohoms L/E=>500Mohms ZS=0.30 rcd trip time 1n28.7 5n18.4

shower r1+r2=0.03 IR= L/N>50Mohoms L/E=>500Mohms ZS=0.31 rcd trip time 1n29.2 5n18.7
only after testing did the owner mention the nuisance tripping. which seems to have been happening for a long time, even when house is empty. House built 1990 original C/U and wiring as far as I know.

 

[davek]

First off, there's there's no pass or fail on an EICR. It's either satisfactory or unsatisfactory with the reasons stated on the report, referenced to the regs.
Now, you limited a circuit or several because you knew they would "fail" but left them connected?
If the place is empty why was there a need for any limitations?
Why are you testing hard wiring with appliances still connected?

Hi Trev I was not testing with appliances connected, jus highlighting what was connected in general,

Dillb Only got inform about the problem after I did testing, so left the appliances connected through out the day while I sorted garage out to see if I could reproduce the trip, but was fine all day.

 

[cprfenom]

hi
here are the circuit and results on the RCD side.
sockets r1=0.19 rn=0.19 r2= 0.36 IR L-N/E =225Mohms ZS=0.40ohms rcd trip time 1n 18.4 5n7.4ms

cooker r1+r2 =0.06 IR L/N.>500Mohoms L/E=>500Mohms ZS=0.30 rcd trip time 1n28.7 5n18.4

shower r1+r2=0.03 IR= L/N>50Mohoms L/E=>500Mohms ZS=0.31 rcd trip time 1n29.2 5n18.7
only after testing did the owner mention the nuisance tripping. which seems to have been happening for a long time, even when house is empty. House built 1990 original C/U and wiring as far as I know.

So when you look at that what jumps out?

What is your Ze and why have you not included R1+R2 for RFC.

 

[telectrix]

bloody wish guys would stop confusing r1 and R1 etc.

 

[cprfenom]

Is the R1 bullying the r1?

 

[Plonker 3]

What were your IR results for N-E?

 

[HappyHippyDad]

I find this article interesting and useful as well Dave and it might give you some ideas:

View attachment understanding RCD's and tripping problems..pdf