ELCB trips

[airdman]

Hi,

The house I am renting is sufferring from an earth leakage problem somewhere and it's driving me mad. I have had an electrician in the house three times and he implied it was my equipment causing a trip, it has tripped with none of my kit plugged in so I started investigating myself.

Situation.

ELCB trips randomly during the day and night with a number of items operating such as dishwasher, oven, hob, kettle, etc. First started with the onset of snow and ice.

Steps.

As a first step, I disconnected every piece of electrical equipment from the sockets leaving only those which belonged to the house. Cooker, hob, dishwasher, extractor fan and boiler. All items switched on and no trip at all for 20 mins at least.I then connected equipment one by one until bingo, a trip. this happened when I plugged in the TV (brand new by the way). I was able to repeat the trip each time I connected the TV.

I decided to plug the TV into another socket on a different circuit to see if it tripped, no trip until I reconnected it in the original socket. I disconnected the Sky box scart lead and a trip. Disconnected the tv and only had the sky box plugged in, trip occurred. I suspected the Sky psu but thought I should check the sat cable, with this removed, no trip. Reconnected the sat feed from the LNB and trip. Checked the sat cable and looks good but appears to be 30mv on the conductor, this cable runs the length of the garden to the dish.

I can consistently reproduce the trip every time the sat cable is plugged in. I suspect the kitchen equipment may be the cause of a cumulative earth leakage, maybe the old induction hob, and the sat cable is the final spike that trips the breaker.

Does this sound plausable? I need to persuade the landlord and electrician to check the hob and also consider the sat cable, maybe insulation is shot as it has been buried for ten years.

Any suggestions gratefully accepted. ut the kettle on

 

[ProDave]

A sky box should be double insulated so should not be the cause unless it's faulty.

More tests are needed, but at one point did the tv trip it without the sky box connected?

You mention ELCB. Is that really what you mean? can you post a picture of the trip in question?

 

[Larnacaman]

From the way your describing things here, i take it that the RCD device is one that protects the whole house and not one section of it, or an individual circuit.... What is the mA rating of your RCD (ELCB is an old voltage operated device so i'm taking it that you mean an RCD??)

Most of the larger household appliances these days produce leakage onto the system via there mains lead connected suppression/protection capacitors being connected L-E/N-E/L-N, ...more so on electronic equipment/appliances. The biggest culprits are fridge freezers, washing machines, dish washers, microwave ovens and the like.

I'm a little surprised you mentioned an induction hob as being OLD, as they haven't been generally available for that amount of time to be considered as old!! But they can have a larger leakage potential than other appliances, so your right to consider the hob as a potential culprit ...lol!!!

That sat cable could well be adding a significant amount of leakage. Is the sat cable buried direct in the ground or within a PVC conduit/pipe??

Really, the electrician that came to check out your problem, should of had a mA leakage clamp meter, he could have then tested each of the suspected appliances/equipment individually, and quickly isolate where the problem, or problems are within the circuits in your rented house. In fact it's the only Sure way to see what's happening, as far as natural leakage currents affecting tripping levels on your RCD device

 

[airdman]

Gents,

Firstly thanks for the swift response.

By ELCB I mean RCD that protects the entire electrical installation in the house, sorry I need to move into the present! Induction hob, again this is incorrect.

The RCD has been replaced with a new one by the sparky and reads 0.03A, no leakage test was carried out by him prior to the change.

The hob is of the solid metal heating element and is a Miele around 10 years old.

I also tried another Sky box and the same result re the sat cable.

Just spoken to the landlord and his sparky will be in on Friday with a new hob to "test" the installation.

I'll keep you posted. Guinness

---------- AUTO MERGE Post added at 18:16 ---------- Previous post was at 18:13 ----------

I forgot to add that the sat cable has been buried directly into the ground with no conduit and has been that way for ten years.

The TV did not cause a trip when the Sky box was not connected.

Cheers. Guinness

 

[Sidewinder]

Sounds like the Sky box sat screen is commoned to the earthing system either via the Sky box or via the general mass of earth and there is capacitive or true leakage of some description?

Best bet is a leakage clamp meter.

Ah, you're in Luxembourg?

Was gonna suggest that perhaps one of the members near by may be able to pop in when passing?

Doubt that now though!!!

 

[airdman]

Hi Sidewinder,

Yep in Lux, great place!

I remade the sat cable even though it looked ok (both ends).

Sounds like I am not completely mad when it comes to the sat cable! I may go get a new reel of cable and run overground to test/prove my theory.

 

[Sidewinder]

Sounds reasonable

 

[Larnacaman]

The chances are, that as the cable has been direct buried a stone /rock or other Sharp object has penetrated the sheath and exposed the inner cable to sever damp or actual water ingress. ...In other words it's ********!!! So, as you have indicated, replace that co-ax cable and this time don't bury it ...lol!!!

I doubt very much if a solid element hob is giving you much leakage, unless there is an actual fault on it, or a build up of gunk between say the frame and a live connection. But no harm in eliminating the hob as a source of leakage....

 

[PC Electrics]

Gents,Firstly thanks for the swift response.

By ELCB I mean RCD that protects the entire electrical installation in the house, sorry I need to move into the present! Induction hob, again this is incorrect.

The RCD has been replaced with a new one by the sparky and reads 0.03A, no leakage test was carried out by him prior to the change.

The hob is of the solid metal heating element and is a Miele around 10 years old.

I also tried another Sky box and the same result re the sat cable.

Just spoken to the landlord and his sparky will be in on Friday with a new hob to "test" the installation.

I'll keep you posted. Guinness

---------- AUTO MERGE Post added at 18:16 ---------- Previous post was at 18:13 ----------

I forgot to add that the sat cable has been buried directly into the ground with no conduit and has been that way for ten years.

The TV did not cause a trip when the Sky box was not connected.

Cheers. Guinness

So, diagnosis by guesswork and substitution then?

Has this 'spark' done any actual testing with a test instrument (eg an insulation or RCD tester or an MFT)