RCD trips every morning between 08.00 and 09.00

[marconi]

The voicemail is not correct, or not totally correct. Let me explain.

The top left ENEL Arriva is where the main supply enters. It is a 32A circuit breaker which will trip on short circuit and prolonged overcurrent (as I described earlier). In its case, the 32A will hold for 1 hour at 1.13 x 32A and definitely trip after one hour on 1.45 x 32A. It is not sensitive to black out or brown out that is voltage because it is a passive device concerned with current effects(-but see later at # below). If it trips then you either have a short circuit fault happening or you are drawing too much current - see the hour figures I mentioned. The output of this circuit breaker supplies the RCD breaker (F202?) immediately to its right and the ds642p.

For clarity the ds642p is three in one unit as I explained in my first message, so this is all one device and the black switches will trip down on shprt circuit, overload or high earth leakage:



Did you do my test to discover if the RCD breakers (F202 and DS642P are active or passive types. If they are active then when the 32A ENEL breaker trips so will these two RCDS - so as the electrician said. But....if they are passive types then they should not trip if the ENEL breaker trips.

Now to # I mentioned above. If you have a short black out or brown out there may be such a brief surge in current upwards as the voltage returns or rises that the ENEL breaker is momentarily passing such a high current that it trips the short circuit mechanism - it is electromagentic functionality so fast acting (immediate) for currents from 3 to 5 times 32A or more (whereas the overload is thermal mechanic slow acting). If it trips it will need to be reset. If this is the case you may be able swap it for a less sensitive characteristic - we will discuss this once we know what kind of rcds you have.

 

[pgrbff]

The Enel Arrivo has never tripped to my knowledge.
The F202 to its right supplies the workshop downstairs which is physically disconnected from all machines and lights when it is not in use.
The single switch, Allogio, next supplies the granny flat.
It is only the ds642p and the elletrostop that all switch off together.

With all the mcbs to the right of the ds642p off, when I switch the Enel arrivo off the ds642p does not trip.

 

[marconi]

This indicates that the F202 and ds642p is a passive rcd devices - good.

The fact that the ENEL Arriva C32A does not trip indicates you have not drawn too much prolonged over current through it or had a short circuit - good.

You are back to checking background leakage current, ramp tests of RCDS wiring insulation resistances, testing individual equipments and appliances, connections, etcetera which have been mentioned by others. A competent, methodical electrician with the right test equipment, knowledge and experience and a bit of an Italian Sherlock Holmes in his nature.

Do your neighbours suffer like you or are you 'unusual'?

Had you thought about inviting out someone on the EF to take a look?

 

[marconi]

If I remember correctly some rural Italian single phase supplies do not have an earthed neutral which is why they mandate two pole circuit breakers. A single phase supply is derived from any pair of L1, L2 or L3. Do your electricity poles have three or four wires strung between them?

What you might ask ENEL is for them to move your home from the current two lines to another pair of lines to see if it makes any difference. You might just be connected to a heavily loaded line. You may have to swap again to try all the pairs of lines.

if it is three phase plus neutral (4 wire) you could still ask ENEL to move you to a lighter loaded phase.

Are you convinced you are not drawing more than 20A through the 642P 0800-0900 and in the run up to this period?

 

[pgrbff]

I don't have neighbours, we are at the end of the line. When they replaced the cables 2-3 years ago it was just for us. I'm not even sure if there is anyone else on this "spur". If there are it would only be small residential. I think we are fed directly from a substation and there are 3, I believe aluminium, twisted cables, possibly 80mm(2), but my memory has always been appalling so don't take my word for it.
It is hard to estimate but the line is probably around 2km long. It crosses a valley so is difficult to measure.
From what I understood there are 3 because I have the option of 3 phase and the non-earthed neutral does ring a bell.

 

[marconi]

I am going to let others follow up on whether you might be better off having a three phase supply and what would be required. It has great merit. Over a long distance lower currents in more conductors is beneficial to reduce volt drop and deliver the same power.

 

[marconi]

0800 to 0900.......

You have 2 fridges and a freezer. Are they frost-free?
To be frost free they have a heater controlled by a timer which is either a 24 hr clock with on/off settings or a stopwatch recording how long the compressor has run and after a predefined time turning on the heater.

 

[marconi]

Rather unusually, all your circuit breakers are Type C eg they are marked C20. In the UK, in the domestic setting they would normally be Type B and marked B20 for example. You might want to ask your electrician why this selection has been made and let us know what he says.

Here is an estimate of the volt drop for each amp of current flowing along the supply to your home where 0.33 V/A/km is the resistance per km at 25C of 85m2 aluminium conductor:

2 x 2km x 1 A x 0.33 V/A/km = 1.32 Volts

using Pigeon cable at:

80mm2 PE Insulated ACSR Conductor with Lighting Down Conductor Mounting - jytopcable

80mm2 PE Insulated ACSR Conductor with Lighting Down Conductor Mounting , View Complete Details (specifications size,chart data,sheet,full form) about 80mm2 PE Insulated ACSR Conductor with Lighting Down Conductor Mounting ,Find 80mm2 PE Insulated ACSR Conductor with Lighting Down Conductor...

www.vwcable.com

So, when you draw say 10A the volt drop is 13V, 20A it is 26V, 30A it is 39V.

Thus if the supply line is energised at say 230V, the voltage at the end of the line will be 230 - 13 - 217V at 10A and 25C ambient. Volt drop will be more in higher ambient temperature.

Items with a motor draw some 5-10 times there normal running current when they start. Your Fluke may be reading very low readings because on the min/max setting the meter captures these brief but large dips in voltage as the motor runs up (on top of any other current being drawn).

 

[marconi]

Is there any socket you can plug temporarily the fridges and freezer in to which is not covered by the ds642P in order to see if the trip stops and moves to another rcd which trips?

 

[pgrbff]

The fridge freezer combo in the area that covers the tripping RCD is not frost free. It is a basic small fridge with freezer above. I do not think there are any sockets not covered by the ds642p that wouldn’t require a 50m extension. Surely there is no time function on such a fridge that would lead the RCD to trip more or less at the same time? Yesterday it did not trip, but the granny flat did. Today it ha not tripped. My feeling is that it is becoming more infrequent.
There are 3 elements that are timed in some way on the ds642p.
A small bronze pump circulating the hot water which comes on for 10 minutes at 06.30 and twice more during the day.
A gardena watering timer that when it operates causes a shallow well pump, less than a year old, to come on for 10 minutes around 06.30.
The solar pump which comes on when the panels reach a preset temp. Usually around 08.30. However I have been present on more tha one occasion when the pump came on without tripping the RCD and the RCD has tripped when there has been insufficient sun to cause the pump to turn on.

 

[marconi]

No a timer is for a frost-free fridge or freezer.

It may not be when equipments turn on that causes the trip but when they turn off. You might want to check the off times for the things you just mentioned.

Is your hob or oven electric? it is a common problem for the electric elements to have earth leakage which can cause rcds to trip. The ds642p supplies your cucina. Might you turn the hob and oven off at its isolator switch when you aren't using them to see if the 0800-0900 aspect of the problem 'goes away'. (I don't want to explain the electrical reasoning just now 'cos I have not the time).

I still think it a good idea (ie. I would do it if I was you) to invite soon an electrician to do the testing and inspection I and others have mentioned because it would rapidly establish the state of your wiring installation and loads connected to it. It also has value in both quality and safety assurance for your peace of mind and your insurers. The Brains Trust which is the EF need some hard information in the form of electrical measurements to consider your problem further. Money well spent. That's my professional opinion - gratis.

I am going out now 1000 UK and will look again after lunch.

 

[pgrbff]

There is no hob or oven beyond the ds642p yet. We currently live in the granny flat. Almost all of the sockets beyond the ds642p are vacant. Bo the timers, watering and water circulation are only on for 10 minutes. Once the solar pump starts it will run all day, but the ds642p has never tripped in the afternoon-evening when the pump would stop.
Given all the problems I have had over the years with the supply, I still can't help think it is the problem.
I am waiting for the electrician to call me. Amongst other things, I'll ask him if he can do some testing.
Can you tell me again what tests@ I'll have to try and work out the translations.

 

[marconi]

I too think you have a poor supply. But first you need to clear your installation of any faults if they exist before remonstrating with ENEL. You may have both installation and supply problems.

DPG - would you advise pgrbff please on I & T, as I see you have been reading the posts. Or someone equally good?

 

[Wilko]

Hi - I know I’m late to the party, so apologies if this has already been covered
1. What type of earthing do you have?
2. Tell us about this solar pump thing you mentioned in the first post. Do you have solar panels? An invertor? Is it attached to your Consumer Unit? If so, I’d disconnect it all and see what happens tomorrow morning .

 

[marconi]

pgrbff: I have more time now and I don't think DPG has seen my post to him.

If you look at Mattg4321 #14 he has listed the important tests and the order in which to do them - the key words to translate are in bold. I will see if I can find some youtube clips you might look at too:

1. Insulation resistance of wiring between L and N, L and E and N and E at 250V and then 500V

2. Ramp testing of the RCDs.

3. With ENEL ARRIVA closed, total earth leakage current measurement using a clamp meter around the incomers and then around the earth conductor to the earth electrode.

and I would add a fourth and fifth

4. Check all connections are tight in consumer unit and kWh meter and do a 'tug' test on all ferrules to check conductors are indeed gripped inside them.

5. Check insulation resistance of appliances both portable and fixed which are normally energised on the circuits protected by the RCDs.

 

[marconi]

electrical wiring - cavi elettrici

electrical testing equipment - apparecchiature per prove elettriche

test di resistenza all'isolamento

250 Volts - 250 Volt

500 Volts - 500 Volt

test di rampa di interruttori differenziali

corrente di dispersione verso terra totale

incomers - cavi di alimentazione principale

earth electrode current - corrente dell'elettrodo di terra

tightness of connections - tenuta delle connessioni

pull test on ferrules - tirare il test sulle ferrule.

 

[marconi]

50m extension cable:

Cavo avvolgitore cavo protonics 50 m Cavo prolunga con dispenser V 111: Amazon.it: Amazon.it

Compra Cavo avvolgitore cavo protonics 50 m Cavo prolunga con dispenser V 111 a prezzi vantaggiosi su Amazon.it. ✓ Spedizione Gratuita disponibile per membri Prime su oltre un milione di prodotti.

www.amazon.it

 

[marconi]

I have asked an eminent electrician of the Electricians' Forum how much he reckoned these tests would cost and how long to do them. For a typical 3 bed house no more than £100 and a couple of hours at most with the right test equipment and competency in its use - this does not include searching for any faults, just the testing.

 

[pgrbff]

Many thanks for all your help. Much more than I would have expected. It has now been 3 days since the last time the RCD tripped, something has changed.

 

[marconi]

I don't want to overly alarm you but could you have a problem with rodents eating cables under the floor or in the loft or in outbuildings? Or ants getting into connections and electrical enclosures?

Have you had a period of wet weather followed by hot weather which has dried out everything?

Could you walk the length of the 2km line and check the conductors are in free space and not bothered by trees, etcetera. Or that no-one is pinching electricity by clamping on to the cables directly.



Please keep us posted.

 

[pgrbff]

I can see most of the lines from the house, and they’re insulated.
We have lots of ghiri, Roman doormice, in the roof space, they keep you awake at night running up and down or eating the roof insulation. 99% of the wiring is not accessible to rodents, can’t say the same for ants.
We had a much, much drier year two years ago. So dry that we had new cracks appear as the 100/200 year old building settled a bit. The buildings are stone with only mud between the stones, no mortar.

 

[pgrbff]

Hi - I know I’m late to the party, so apologies if this has already been covered
1. What type of earthing do you have?
2. Tell us about this solar pump thing you mentioned in the first post. Do you have solar panels? An invertor? Is it attached to your Consumer Unit? If so, I’d disconnect it all and see what happens tomorrow morning .

Earth is a copper plated steel rod approximately 1,5m deep
The solar pump circulates water from solar panels on the roof for indirect hot water. No photovoltaics, too expensive here.

 

[Wilko]

Earth is a copper plated steel rod approximately 1,5m deep
The solar pump circulates water from solar panels on the roof for indirect hot water. No photovoltaics, too expensive here.

Hi - just a simple thing, but perhaps have a close look at the rod and the cable linking back to your board. Check cable is continuous and the connections at each end are sound and corrosion free.

 

[HappyHippyDad]

Like Marconi says it would be best to get an electrician out to do all the required tests. However, if you intend to fault find yourself then i would slowly, over time eliminate all appliances one by one.

If the tripping is everyday between 8-9 then that is perfect as the tripping is consistent rather than random. You can just unplug/switch off one item and see if it still trips the following day. It would need to be a controlled experiment though. Just unplugging something and seeing if it fails to trip the following day would not be enough. I would then plug it back in and see if it then trips the following day. This would add to the degree of certainty.

Even if the above does not work it has still eliminated some possible causes and you can then focus elsewhere. i.e the supply, faulty RCD's etc etc.

Hopefully your tripping problem has gone away (as you have said), but I have had a few customers who cancel on me because it stops tripping. Only to get a phone call the next day apologising and asking me back as it has started again.

Also, It would be worth spending the money to get it properly checked even now, as if it has been tripping that often then something was clearly very wrong and may still be there even though it's not tripping now.

 

[pgrbff]

Still waiting for the electrician, his son and father are both in hospital and I am not that close to where he lives.
After a month of problems with the mainboard tripping virtually every day at more or less the same hour, it has now been over a week since the RCD tripped. The annexe board, however, has started tripping again, only three times in 8 days, all in the morning, but I'm not sure we are ever going to get to the bottom of this.

 

[static zap]

but I'm not sure we are ever going to get to the bottom of this.

--if you keep a calendar ,add weather ,temp ,rainy days ...
May have some clues.
(and clues -when to call again next year)
...If you move any equipment about ..
add dates if (just in case any patterns change)

a) Others hammering the fans/air-con
b) Water seeping in somewhere & drying out.
c) Overnight condensation-re distributing.
----There is a chance damage is being done -and will eventually become a Permanent thing---

 

[pgrbff]

I have kept a diary and unfortunately, over the last 3 /4 years it has been fairly random. We have periods where the RCD regularly trips, and then it stops for a while and the pattern changes.
Some trips are expected, we had storms the last few days and the RCD in the annexe switches off, and when it snows in winter.
The voltage varies all day and we have regular blackouts.

 

[marconi]

Would you consider spending money on a battery and inverter which would power your home and annexe? The mains supply would be used to charge the battery. When the supply is of the correct voltage the inverter could be set up to go into 'bypass mode' connecting the supply to the loads avoiding discharging the battery; otherwise when the input voltage is out of specification the inverter automatically switches to the battery with no loss of output voltage. You could also buy an inverter which would take an input from solar panels.

Here are some prices for different sized(kVA/kW) inverters:

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

You would also need some batteries - good ones which I can talk about if you are interested.

 

[pgrbff]

I have considered using solar but the incentives here aren't very good anymore.
I really need to formally complain to Enel again, my electrician keeps telling me to do so, but they have already replaced two/three km of lines to my home with what they say are the heaviest permissible. I'm not convinced that it is simply a case of being too far from the substation but basically, I would have to pay for monitoring and dealing with the bureaucracy here is nothing short of a nightmare.
I have to go away for a few days now and will have to ask my nearest neighbours, an elderly couple, to drive up at least once a day to check nothing has tripped. This is worse than it seems because the road is in a terrible state, missing tarmac in may places.

 

[pgrbff]

I

Would you consider spending money on a battery and inverter which would power your home and annexe? The mains supply would be used to charge the battery. When the supply is of the correct voltage the inverter could be set up to go into 'bypass mode' connecting the supply to the loads avoiding discharging the battery; otherwise when the input voltage is out of specification the inverter automatically switches to the battery with no loss of output voltage. You could also buy an inverter which would take an input from solar panels.

Here are some prices for different sized(kVA/kW) inverters:

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

You would also need some batteries - good ones which I can talk about if you are interested.

I would like to use at least some solar but the way it works in Italy, as I have understood it, is that a company looks at your usage, installs panels that should cover that usage for free, then you continue to pay your electricity company more or less what you were paying before to rent the panels.
I have friends that have bought their own panels, costing between €4500 and €20,000 and none of them have had any payback from their electricity companies. They even pay a monthly charge to rent the new solar electricity meter.
I have always thought that batteries would prove too expensive. I use lipos in my hobby, flying radio control helicopters, and apart from the cost they don’t seem to have that many charge cycles.
If I could incorporate a battery system that might actually save me some money over time I would certainly consider it.