Freezer tripping electrics?

WIAWSNB

ka7e said:

Well, it tripped again this morning.  It didn't trip yesterday and the only things I'd plugged in since then were washing machine, tumble dryer and air fryer.

Confirm, please - it's the main RCD power switch that trips - ie, everything is cut when it goes 'pop'?

Strongly suggest you first try tackling this yourself with a process of elimination.

Photo of your CU? How many MCB/circuits does it have? 

Turn one off before you go to bed. Turn it back on at 9am. Turn the same one off again for a good 3 nights. Then move on to the next.

It might not work. Removing one whole circuit like this could drop the overall accumulated 'leak' down to a level where one miscreant circuit/device no longer has the effect of tripping it. But, if it trips with one circuit isolated, then that's one down.

Deffo include the PV system in this. Does it have a dedicated breaker in the house CU? If so, that's all you need to do - flick it there. 

Section62

WIAWSNB said:

ka7e said:

Well, it tripped again this morning.  It didn't trip yesterday and the only things I'd plugged in since then were washing machine, tumble dryer and air fryer.

Confirm, please - it's the main RCD power switch that trips - ie, everything is cut when it goes 'pop'?

Strongly suggest you first try tackling this yourself with a process of elimination.

Photo of your CU? How many MCB/circuits does it have? 

Turn one off before you go to bed. Turn it back on at 9am. Turn the same one off again for a good 3 nights. Then move on to the next.

It might not work. Removing one whole circuit like this could drop the overall accumulated 'leak' down to a level where one miscreant circuit/device no longer has the effect of tripping it. But, if it trips with one circuit isolated, then that's one down.

Deffo include the PV system in this. Does it have a dedicated breaker in the house CU? If so, that's all you need to do - flick it there. 

Remember that turning off an MCB doesn't fully isolate a circuit.  Appliances need to be unplugged and/or disconnected with a douple-pole switch/isolator to fully remove them from the equation.  Otherwise the neutral conductor can provide an earth-leakage path.  If there is a neutral-earth fault in the fixed wiring then even removing/isolating the appliances won't work... but you'd hope the electricians did enough instrument testing to rule that out....

WIAWSNB

Section62 said:

Remember that turning off an MCB doesn't fully isolate a circuit.  Appliances need to be unplugged and/or disconnected with a douple-pole switch/isolator to fully remove them from the equation.  Otherwise the neutral conductor can provide an earth-leakage path.  If there is a neutral-earth fault in the fixed wiring then even removing/isolating the appliances won't work... but you'd hope the electricians did enough instrument testing to rule that out....

Fair point, but we are talking about what is reasonable to manage as an ongoing task. 

If the OP would like to unplug every single item (unless socket is DP) and light fitting from each circuit instead, then fill boots. 

As an initial step, this would be a painless way to hopefully eliminate some circuits, and possibly even ID the culprit.

But, from my own experience, nuisance tripping is a right pita to ID. And mine ultimately resolved itself. Actually, it may have been my inverter - I replaced it as it had gone kaput. Trying to remember if it coincided.  

ka7e

Scrounger said:

ka7e said:

2 lady sparks visited today ... 

I had a bad feeling about this even before I learned of their 'solution'.  


Scrounger

We have a lot of female sparks and tradespeople here - home of the biggest construction site in Europe, Hinkley Point C power station.

Heedtheadvice

I think you are reading a sexist bias into that response which probably does not exist. I have worked professionally with electricians and engineers of all types and some are poorer and less competent than others irrespective of sex, ethnic origin,  age  and trade body membership etc. One still comes accross forums where qualified and supposedly competent electricians ask basic questions with a variety of correct and incorrect replies often at odds with the IET guidance that all should know amongst other regulation/law.

The the problem you have is owing to insulation resistance that is too low producing a leakage fault current from either live, neutral or both to earth. As I posted earlier this is comprised of all circuits being supplied by the RCD and is both a static ( effectively continuous) level and dynamic ( I.e. intermittent or short term) leakage at switching or similar times.

The static level is easy and straightforward to measure and also to find those that have big contributions to the leakage. Often those measurements can be enough to find issues. It can be typically the frequent measurement and only test needed to have a properly working loaded circuit.

In your case indications ( the time element ) are that that there is a dynamic contribution to the fault. A good competent electrician should take that into account  and have the necessary knowledge and equipment to analyse the fault and effect the proper cure.

It may be that the MCB was wrongly rated ( at distance we cannot tell) but it must match the circuit rating which it protects ( not what is connected).

It does not affect or measure the leakage and it would be reasonable to assume,  for the two electricians that visited,  a full insulation analysis has not been done. As you have found out, it has not prevented the RCD trip.

So if all the info you have supplied is true and complete then to question the competence of the electricians you have employed must be reasonable.

I comment not as a DIYer but as  a professional engineer with many a year under my belt in design, contruction, testing/proving and fault analysis.

Scrounger

ka7e said:

Scrounger said:

ka7e said:

2 lady sparks visited today ... 

I had a bad feeling about this even before I learned of their 'solution'.  


Scrounger

We have a lot of female sparks and tradespeople here - home of the biggest construction site in Europe, Hinkley Point C power station.

Six years late and £28bn over budget:

http://www.telegraph.co.uk/news/2025/06/10/hinkley-point-c-blueprint-for-sizewell/

Anyway, are you having them back for another go?


Scrounger

ka7e

Scrounger said:

Six years late and £28bn over budget:

http://www.telegraph.co.uk/news/2025/06/10/hinkley-point-c-blueprint-for-sizewell/

Anyway, are you having them back for another go?


Scrounger

And dont we know it! The whole project has ruined the infrastructure of what is quite a small town. We're overrun with HMOs for the workers and rents are on a par with Bristol. It employs a lot of locals, but thousands more are transient or ship in Mon-Fri. When station C is complete (and the slippage changes evey year) we have decommissioning of A and B to contend with.

Anyhoo, I will give the company a chance to come back and properly investigate the trips with a view to sort it or else!

ka7e

There may be some Brownie Points for WIASWNB - after testing and conferring with colleagues, sparks today think it is the solar inverter. It didn't trip this morning and it has been overcast all day. It has been disconnected and we'll wait a couple of days to see if the tripping stops. It should still be in warranty and I'm using the same firm that installed it, so hopefully not an expensive problem to solve.

Heedtheadvice

So the mcb upgrade fixed it? 😀

Did they measure the insulation  resistance of the circuits and appliances connected and record the results?

But if it is the solar system  and still under warranty ( for the cause of the fault) and gets repaired for free that is good news.

ka7e

Heedtheadvice said:

So the mcb upgrade fixed it? 😀

That was a big fat no!

Did they measure the insulation  resistance of the circuits and appliances connected and record the results?

Yes to former - it was the time element and the fact it hadn't tripped that overcast morning that led them to the inverter. Sunny this am and no trip (inverter disconnected).

But if it is the solar system  and still under warranty ( for the cause of the fault) and gets repaired for free that is good news.

Hopefully!

..........