Earth Leakage Problems

Are you saying that you are having intermittent interruptions of power to your house?

If so, it does not sound as if you have a problem in the house. It may be the connections at any of the utility conductors. In the US we would ask the utility to install a recording volt meter and monitor the voltage for several days. That would confirm whose problem it is. I don't know if the utility in Spain does this kind of tests..

No, The supply to the house is constant and without interuption, however, I do not know if there are voltage fluctuations with the supply. Even if there are, then a lot of people in the same area would be experiencing the same problems, therefore I feel that the problem is within the house circuits or appliances.

Thanks,

John

What exactly is this ECU? Is it connected between your main supply and the rest of your other circuits?

While the process of elimination may be effective, are you going to cause a dangerous potential problem by bypassing the ECU? The answer may be "YES" depending on what the ECU is supposed to do.

Can the proposed process of elimination fail using method as described? Again, the answer is "YES" if it requires two or more circuits to create the problem.

Can you test the ECU by itself? It may be defective! How about a little more information about this ECU device?

Hi

Thanks for replying,

The ECU is between the main supply breaker and the individual circuit breakers for the different parts of the house. In other words, the ECU is the earth leakage protection unit for the whole house.

Whilst taking this unit out of the equation as mentioned above, the breaker units are bi polar, so that in the event of a problem, either on the negative side, or the positive side would trip in the event of a serious fault. Ie short to earth or direct short.

The ECU has a test button on it and this seems to check out OK, but, as you say, it could be faulty, but I dont think so at this moment in time.

Since posting this thread, I have bypassed the ECU and checked ALL applliances in the house and all sockets and lights. All work fine with no residual voltage that can be detected, and certainly nothing is Live to the touch!......So at this point, I am waiting to see if any of the main breakers trip.

I´ll keep you informed!

Ta,

John

What concerns me is the 30mAmp limit you mentioned. With the ECU installed as you described, it sounds to me as if the sum of the leakage current must be less than 30mAmps.

Because all of the loads are in parallel with respect to the ground (or earth) connection, then a very small leakage from each circuits (through each breaker) would be added together. In the USA, we use GFCI (ground fault current interrupter) outlets for protected areas. They trip at 10 mAmps.

I don't understand why anyone would want to protect their entire house against such faults. Some kinds of old electronic appliances or other equipment may have circuits which generate brief leakage currents (including Radio Frequency losses).

Did you say that this was something new?

I rated NotUrOrdinaryJoe's reply as a good one, and would like to amplify on it. First of all, disabling the ECU and looking for breakers to trip isn't going to happen. Breakers trip at or above their rated current, due to excessive current in the breakered feeder. The ECU trips at 30 mA leakage current, which is an identical low value of current in both the phase and neutral conductors. The difference between the breaker trip point and the ECU trip is orders of magnitude - which is why they put the ECU in, in the first place. Like the previous responder, I can't figure out why you would shutdown the whole house because one branch had some leakage current. But then I'm in the USA, w/o special insight into the rationale behind EU standards. Next, if you disable the ECU and you had a device or devices which together generated just over 30 mA of leakage current, the point at which the leakage current was being driven to ground would be at a potential relative to ground of the leakage current multiplied by the ground resistance. That ground resistance should be under one Ohm, so that the case of the unit generating the leakage current (if it were all sourced from one point) would be at 30 mV or lower ac potential. You aren't going to feel that. If you think that some device is leaking that way, put it on a cheater plug (open-circuit the green safety wire), and let the case charge up to line potential. Then you'll feel it! It won't be a hazard, because the source impedance of the leakage current is high, over 7000 Ohms, to generate 30 mA from 220 Volts. But you'll feel the tingle. It was the radio frequency comment, however, that prompted me to write. There has been a history of rfi (radio frequency interference) problems with some models of GFI (ground fault interrupter) type devices. After all, they are looking for a small amount of common mode current in the ac wiring, and that isn't hard to come by if someone keys a nearby rf transmitter. I'm not definitively stating this is the cause, but it fits with the intermittent nature of the problem. I'm not talking about a licensed BCB (broadcast band) transmitter, because they will likely be some distance away and also they are on continually. I'm thinking more of a neighborhood amateur radio transmitter, or maybe someone driving by the house with a relatively high power mobile transmitter. Like police or ambulance maybe? Maybe you live near an airport and get some of the ground-to-air and air-to-ground radio traffic? Does Spain have the equivalent of the trucker who is supposed to transmit 5 Watts on his citizens' band radio, but is transmitting a couple hundred illegally? If you suspect rfi might be the problem, check out the CE compliance sticker on the ECU (or in its manual) and look at when the CE sticker was applied. Not saying you want to go this route, but you could in theory find out what, if any rfi requirements were imposed in order to get that CE sticker, and see if any newer devices were out there with better immunity characteristics. There is a product standard for ECUs. It in turn calls out rfi requirements EN61000-4-3, and EN61000-4-6, which would both bear on this issue. You could see what levels it was supposed to meet, and compare those levels to possibly higher levels of immunity built into newer units. The whole point of the EU nanny state is to levy so many requirements and restrictions that this type of thing just doesn't happen! So maybe, it's just your imagination :-)

Hi there, Have you check your appliances or any unit from the plug connection if the connection of nuetral and live wire is reverse sometimes this caused you a problem and trigger your ECU to trip off. check your aircon, ref,washer, dryer etc. if your neighbor don't experience same problem with you using the same system then either one of your appliances got partial ground., also check or replace your ECU.

i had a simmilar situation in my house ,and the problem desapeared as mysteriously as it had come .after 2 days of inturuptions.

why dont you try to megger your installations/equipments insulation resistance especially to ground ?

Whole-house units on TT earthing systems in the UK used to be 500mA. A recent upgrade locally rates the trip at 100mA. There are 30mA units downstream of it.

Hi Folks, most likely cause of this is a neutral to earth fault, check all of the ring main outlet for chaffing of the neutral where they enter the boxes behind the fittings. or turn off the mains , disconnect the earth and neutral connections and megger between them on the house side of the circuits then one by one remove the neutrals for each circuit, when you loose the earth fault the last circuit disconnected is the one to examine in detail

Intermittent electrical problems are difficult, but try this.

1) Rather than bypass the ECU, consider systematically turning off the power to certain sections of the house.

2) Record what appliances are operating during the earth fault, and try to narrow it down via process of elimination

3) If you narrow it down to an air conditioner or furnace, consider worn thermostat wires, or loose aluminum insulation within the unit. Good Luck!

Guys,

I have just had a very similar situation.

Here in GB we have a new set of regulations this year whereby any significant changes to electrical wiring in your house, now have to be approved ( measured, checked, passed and a certificate signed off by a competent person).

The competent person has to have had the government course, examination and whatever and be appropriately certified.

I am about to do some more work on the house and needed another couple of circuits; this meant a new Consumer service Unit (UK terminology). {{A CSU contains the main breaker, a set of MCBs and at least one RCD to cover a set of circuits. A CSU can still cater for RCD and non-RCD circuits}}

I could do this myself but it would have to be certified by a competent person, so why not get a competent person to do the work! You got; I hired someone.

After he had wired the system and gone home we started to get whole house trips. Never before.

Now he had wired up 6 Non RCD circuits, say and 8 RCD circuits (RCD=Residual Current Devices).

It turned out that he had two of the neutrals crossed over-!! That is one neutral from an RCD circuit was connected to a non-RCD neutral bar and vice versa.

After he put that right and went home the house continued tripping.

The following day I pointed out that one of the RCD circuits was feeding my Garage CSU which has it's own set of RCDs.

So he stripped down the CSU that he had installed and moved the Garage feeding MCB to the non RCD stack and apart from some minor issues which involved meggaring every socket/outlet -competely successfully I might add, all appeared well.

This part was just tiresome since it involves removing every load or even part load from each circuit before it was measured - and I had some tiny neons inside switches which showed up on the test so out they all had to come!

Since then we have had no trips.

We have to be very careful with our experts.

And make sure that we do not get RCDs in series!

And just to put some more perspective on this - I am a member of the IET (almost 50 years) which in the UK writes all the apprpriate regulations and when the trips went off for the 4th time in the middle of one night I started to compose my letter of resignation!! Before my wife did it for me!!

Happy days.

Sleepy

Hi Everybody,

When I first started this thread with the problem I have encountered, I hoped that I might receive one reply that might point me in a direction that I had not thought of.

I must say that I am overwhelmed with the replies you guys have given me and given me very useful information to a problem that obviously in the past has given many people plenty of grief!

Regrettfully, I have to be away for a couple of weeks before I can track this one to ground so it were (pun not intended!), however on my return, I promise that I will post whatever discoveries that I find.

Once again, thank you to all that have taken the time to reply,

An ever grateful,

John

Buenas dias John,

Exemmet has the most likely solution to the problem. As you have double pole breakers the best way is to test each circuit with a megger. You will not need to disconnect anything other than to open the breaker, and then test each leg to ground.

I suspect, like Exemmet that the problem will be a neutral side leak.

In Spain the RCD / ELCB / GFI is known as an "interuptor diferencial" which, apart from the spelling differences explains exactly how it works.( >30mA difference between the L & N currents causes a trip).

Bearing in mind the fact that the neutral is bonded to earth at the transformer supplying your area you will see a small voltage difference between N & E dependant on the load on the circuits supplied by that transformer (typically a few volts).

Now, if there is little difference between N&E due to a very good phase balance or very light load then a leak from the neutral side of say your water heater element will pass very little current, not enough to trip the diff. If somewhere on the same distribution system, one of your neighbours connects a heavy (1ph) load then N-E voltage increases and your diff will trip due to simple Ohms law where R is the leakage resistance and V is the N-E voltage.

An interesting point here is that some items such as household electronics like laptops, TVs etc. with switch mode power supplies, which are seen as a low power loads, often cause this type of trip because they draw an enormous start-up load as the internal capacitors charge thus causing a large spike in the N-E voltage.

The water quality in many parts of Spain is poor with a corrosive effect on water heater elements. Check that first then on to washing machine, dish washer, water pump, pool pump etc.

Suerte y Saludos

Chas

In Australia an ELCB protects individual circuits, except the stove/oven as they tend to have Leakage current period.

I have never heard of until now a whole domestic installation being covered by this one breaker, but rather individual circuit's being protected independent of each other.

However, we do have a main switch that cuts power to the whole installation.

As stated before, it is advisable to increase your ELCB range >30ma if possible or remove the oven/stove from this and run an independant circuit to it and even the Hot Water system.

This by rights should eliminate the tripping of the ECU Unit.

Worth a go.

Regards

JB

Hi john,

use mega tester to check the breaker circuit and all the equipments connected to the power socket individually. The problem is having bad insulation problems.

Cheer....

No expert but similar problem also in spain. I think that my problem may be due to dampness in the ground after heavy rain. Could this apply in your case? I have a leakage from N to E to an outside light. The trip took a longwhile before I could get it to stay on. A coleague suggested that I should replace it as the 'trip resistor(?)' can degrade after constant tripping.

Hi Jime,

Your problem is almost certainly just leakage at the outside light. It is quite typical that the wall plate of the light does not have enough space to accommodate a waterproof box so the connections are usually just made with a connector block and some insulation tape. The answer is to remove the light, replace the connector block and put it in a drip proof enclosure. A good source for these used to be 35mm film canisters but are a bit rare now.

Your "interuptor diferencial" won't be degraded by tripping usually. The main breaker, if it trips, does suffer and after repeated tripping will trip earlier (easier) than it should.

Saludos

Chas