Reasons why this RCD keeps tripping?

[lozcozard]

Does anyone know why the attached RCD keeps tripping? It’s for the plug sockets. Not tripped for a good few weeks then this evening tripped about 4 times at about 1 or 2 minutes apart now seems to stabilise again.
Thanks

 

[JohnD]

has it rained today?

did it rain much over the last few weeks?

 

[Harry Bloomfield]

Does anyone know why the attached RCD keeps tripping? It’s for the plug sockets. Not tripped for a good few weeks then this evening tripped about 4 times at about 1 or 2 minutes apart now seems to stabilise again.
Thanks

.
As it is for sockets, the obvious first thing to try when it is tripping often is to unplug everything plugged into that circuit. If it still trips, you need to investigate the fixed wiring, if not then the problem is something which you have unplugged. It may require several attempts to be certain you have found the problem.

The actual problem will be either a leak from live to earth, or neutral to earth.

 

[oldbutnotdead]

has it rained today?

did it rain much over the last few weeks?

Yeah that. Are there any outdoor devices (security lights, cameras, hot tubs, sheds) fed via that RCD. Don't go thinking it has gone faulty- that is possible but it is much more likely to be responding to a fault condition.
That RCD will be feeding other circuits as well as the 'plug sockets'- a wider pic would help

 

[ericmark]

Back in the 90's I returned to UK to find the RCD revolution, the big problem was neutrals not switched, so simply switching things off to locate the cause of tripping often did not work, and I ended up getting the tools out to disconnect things to test.

It has all moved on since then, in the main down to getting use to common causes, but also change in practice, like double pole switch to outside lights.

RCD construction has moved on as well, the old non electronic in my old house would trip due to spike on the line, and they did seem to have bouts of tripping, maybe go two years without a trip, then 4 times in a month, and no cause found, I have wondered if next door was using a welder and that was the cause.

However main thing to remember many items still only switch line, so a toaster left plugged in but not used can cause a RCD to trip when the kettle is used, so step one unplug anything not in use. Damp is a big cause of earth leakage, and electric items tend to produce heat when used, so a TV full of dust may not cause a problem used every day, but left for a month that dust gets damp and causes a problem, and of course the more plugged in the less each needs to leak to cause a problem.

As already said we look for water ingress, outside lights, and mineral insulated heating elements, there are many in the home, kettle, immersion heater, washing machine, tumble drier, and frost free freezer to name just a few, the mineral is hydroscopic that is it attracts water, the end should be sealed, and once the element is used it drives out any water which has got in, so often there is a problem with a cooker which has not been used for two months while on holiday, but not when used daily. Freezer is a real problem as the defrost element is on a timer, and only works when motor is not running, and you may unplug the kettle to test, but unlikely you unplug the freezer, so it can cause what seems to be random tripping.

 

[lozcozard]

Thanks for all your replies.

sorry for the late reply but it’s taken me ages to find what I think is the issue.

The RCD only trips when my old Plasma TV is on. But not just on, even in standby, so just plugged in. I’m sure I even had a trip when it was plugged in but off and not on standby.

Its taken ages to find because it doesn’t trip immediately when you turn it on. Sometimes it’s soon after, sometimes it’s ages after, and once a few days ago it didn’t trip at all when it was on standby. Nevertheless I only have the trip when the TV is plugged in.

I haven’t moved the tv or anything it’s been there years. I have recently added a second hand sound bar onto the same circuit I don’t think it did it before then. Soundbar seems ok.

anyone have any ideas, or could the TV be end of life, it’s about 11 or 12 years old.

thanks

 

[conny]

Recently adding a second hand sound bar immediately raises suspicions.
Leave the bar disconnected for a while and see if it still happens. If not plug the sound bar back in and if it starts happening again then there's your culprit.

 

[winston1]

Does the TV or soundbar have an earth lead? An RCD trip requires leakage to earth. Most TVs are double insulated so in themselves cannot cause a RCD trip. Leakage to earth can only happen through connected equipment which has an earth. Possibly soundbar if it has an earth or the TV aerial.

 

[ericmark]

A TV is an odd one out, the RCD measures power in and power out, and if not same it assumes some power must be going else where so that would be earth. As @winston1 says many TV's don't have an earth pin on the plug, so at first glance nothing can go to earth, however I remember getting a tingle from a TV from the aerial connection, I was told by manufacturer that it was permitted to have a small leakage to aerial, however I felt getting a shock when up a ladder adjusting aerial may not kill you, but letting go of the ladder and resulting contacting the ground may, so took TV back.

So it seems some TV's could send current to earth through the aerial, and I would think any other earthed item plugged into the TV, in the main switch mode power supplies do isolate, however the interference suppressors/filters often had connections to earth, and a capacitor failing could very well result in it tripping a RCD. The same applies to filtered sockets.

I have found only way I can check for leakage is my PAT tester, I can test with an insulation tester but that is DC, and I suspect you have neither. So looking for tests without testers, so as already said you can try unplugging sound bar, and unplugging the aerial, if the latter is the problem then there is an easy cure, CB and Amateur radio could some times mess up TV, so a device called a braid breaker was sold which allowed the AC TV signal to pass, but not any DC signal or out of band AC signal, one of these will stop the TV earthing through the aerial. Also the aerial sockets which divide the signal into VHF, and UHF will do the same, however if you have a mast head amplifier it would also stop power going up coax to feed that.

 

[bernardgreen]

many TV's don't have an earth pin on the plug, so at first glance nothing can go to earth,

With no Earth connection, just Live and Neutral, the 0 volts ( chassis ) of the circuitry inside the TV will drift around the mid point of Live and Neutral ( about 115 volts ). This voltage is the result of stray capacitive coupling. Hence the tingle when you touch the aerial connector. Depending on the amount of stray capacity the tingle may be mild or strong.

It would seem unlikely that stray capacitive coupling be could be large enough to produce 30 mA to tingle an RCD into tripping. But add a DVD player and other essentials to the system and the combined stray capacity might create enough current to Ground via aerial cable or other path to trip an RCD

 

[ericmark]

It would seem unlikely that stray capacitive coupling be could be large enough to produce 30 mA to tingle an RCD into tripping. But add a DVD player and other essentials to the system and the combined stray capacity might create enough current to Ground via aerial cable or other path to trip an RCD

I agree however my point is even with a plastic earth pin a TV can still be connected to earth. I know theory you should not earth an aerial, earthing an aerial increases the chances of a lighting strike, however often they are earthed as the back box is common for socket and aerial so earthed through back box.

 

[bernardgreen]

I know theory you should not earth an aerial, earthing an aerial increases the chances of a lighting strike,

I think the jury is still out on that one, and has been for many decades......

Aerial masts are earthed to discharge static created by the wind,

And then there is the theory that having sharp pointed metal fingers on the roof pointing upwards and connected to a good ground rod creates an electric wind ( or ion wind ) which discharges the static charge in the air before it can create a strike.




Ion wind, ionic wind, coronal wind or electric wind is the airflow induced by electrostatic forces linked to corona discharge arising at the tips of some sharp conductors subjected to high voltage relative to ground. Ion wind is an electrohydrodynamic phenomenon. Wikipedia

 

[ericmark]

I have seen the copper globules that was a long wire aerial after a lighting strike when aerial grounded, a 50 mm² cable may survive a strike, but under that very little chance, so either use something that will survive the strike, or don't connect to earth. But with a loft aerial there is no reason not to earth, and with my old house aerial was half way down the wall around 10 foot off the floor positioned so it would not see Winter Hill, only Moel-y-parc so at that hight again may as well earth it.

But my instructor said no sharp edges, and not earths, so should not be fitted to gable end or a soot lined chimney yet you only have to look around any housing estate to see very few obey that instruction.

However thread is about RCD tripping and only reason for saying about the aerial is that could be a path to earth.

 

[lozcozard]

Thanks again.

it’s stopped happening at all now. We’ve watched loads of tele and had it on all day including the soundbar with no tripping.

So I was unable to test if it’s when the soundbar is on with the tv.

So even more stumped now! I don’t know if it’s fixed or the issue still there and will come back.

I don’t have an aerial going direct into the tv but the foxsat hdr box with hdmi to the soundbar then hdmi from soundbar to TV. I also have an Apple TV same setup, hdmi to soundbar, then hdmi to tv.

 

[JohnD]

not much rain recently.