Earth leakage tripping with no load ?

[Derlyn]

Hi all

Just a little video as promised ( a man of my word ) made on 4th Feb 2020 showing that an earth leakage relay does not trip on a neutral earth fault without a load connected.

Please forgive the filming quality. I am an electrician and not a film maker.

https://www.youtube.com/watch?v=jxG3KFppbZc

Peace out .. Derek.

[skatingsparks]

Er. And?

[Frans400]

Help me if I'm wrong guys but dis is not a problem because there will be no current on the neutral wire and when a second appliances(load) is connected it will cause the RCD to trip.

[Derlyn]

Er. And?

I made this video in response to a number of active forum users who were / are under the impression that all earth leakage relays will trip on an earth to neutral fault even with no load connected. Not so.

Peace out .. Derek

[Derlyn]

Help me if I'm wrong guys but dis is not a problem because there will be no current on the neutral wire and when a second appliances(load) is connected it will cause the RCD to trip.

Exactly.

Peace out .. Derek

[ians]

I am curious to figue out why my earth leakage unit trips when I perform a similar test ...but Dereks unit doesnt.

I need to figue how a 14 mA leakage current is displayed on the leakge current tester prior to it tripping without a load connected ... in fact both the test earth leakage and the unit in my sub DB trips shortly after the test bench unit trips ... i am going to bypass my Sub DB earth leakage unit

John Ward explains in in a really simple manner ... as i have mentioned ... I understand that a leakage current of around 20-30mA or an unbalance between the live and neutral is required to trip the unit ... but what i dont understand is why my unit trips on the work bench ... what is creating the 14 mA displayed on my leakage current tester ... if no load is connected (ideal situation).

in 99.9 % of the cases where the earth leakage has tripped when i touch the neutral ... the earht leakage has always been connected in a DB ... never a test bench situation ... when i carried out the test on my workbench I was hoping it wouldnt trip ... the only difference betwee nmy test and Derecks test ... I didnt use a plug and plug top ... i just touched a piece of wire between earth and neutral.

https://www.youtube.com/watch?v=JTkuoMplER8&ab_channel=JohnWard

[Jaws]

I am curious to figue out why my earth leakage unit trips when I perform a similar test ...but Dereks unit doesnt.

I need to figue how a 14 mA leakage current is displayed on the leakge current tester prior to it tripping without a load connected ... in fact both the test earth leakage and the unit in my sub DB trips shortly after the test bench unit trips ... i am going to bypass my Sub DB earth leakage unit

John Ward explains in in a really simple manner ... as i have mentioned ... I understand that a leakage current of around 20-30mA or an unbalance between the live and neutral is required to trip the unit ... but what i dont understand is why my unit trips on the work bench ... what is creating the 14 mA displayed on my leakage current tester ... if no load is connected (ideal situation).

in 99.9 % of the cases where the earth leakage has tripped when i touch the neutral ... the earht leakage has always been connected in a DB ... never a test bench situation ... when i carried out the test on my workbench I was hoping it wouldnt trip ... the only difference betwee nmy test and Derecks test ... I didnt use a plug and plug top ... i just touched a piece of wire between earth and neutral.



https://www.youtube.com/watch?v=JTku...annel=JohnWard

Hi Ian

I haven't looked at the video, but thinking about a possibility:

In an electrical circuit with a solid grounded neutral or star point the earth and neutral must be at the same potential. The voltage / potential difference between a live and neutral conductor must be exactly the same a the voltage measured between a live and ground conductor. And the voltage measured between neutral and earth should be 0 V.

But in practical circumstances this is not always the case. So if the voltage difference between Neatral and Earth is sufficient to allow the Earth Leakage to detect a current flow of its rated current it will trip when you connect the earth and neutral down stream of the Earth Leakage device without any current flowing in the live conductor / or have a load connected.

[Justloadit]

I am curious to figue out why my earth leakage unit trips when I perform a similar test ...but Dereks unit doesnt.

I need to figue how a 14 mA leakage current is displayed on the leakge current tester prior to it tripping without a load connected ... in fact both the test earth leakage and the unit in my sub DB trips shortly after the test bench unit trips ... i am going to bypass my Sub DB earth leakage unit

John Ward explains in in a really simple manner ... as i have mentioned ... I understand that a leakage current of around 20-30mA or an unbalance between the live and neutral is required to trip the unit ... but what i dont understand is why my unit trips on the work bench ... what is creating the 14 mA displayed on my leakage current tester ... if no load is connected (ideal situation).

in 99.9 % of the cases where the earth leakage has tripped when i touch the neutral ... the earht leakage has always been connected in a DB ... never a test bench situation ... when i carried out the test on my workbench I was hoping it wouldnt trip ... the only difference betwee nmy test and Derecks test ... I didnt use a plug and plug top ... i just touched a piece of wire between earth and neutral.

I suspect that you have a potential difference between Neutral and Earth on your incoming side, which causes a current to flow from the Neutral to Earth through the ELU when you short them out. It sees this imbalance of current and trips.

[ians]

I decided to do a few tests to see why any earth leakage I test in my workshop when I touch neutral to earth ... it trips the earth leakage unit.

Did the same setup as above ... connected the plug to the light circuit for the test(not on earth leakage) everytime i did the test both the test unit and the earth leakage in the DB tripped.

The readings vary slightly.

L-N=229.2 VAC
L-E=230.6 VAC
E-N=2.1 VAC

Hooked the leakage current clamp to the neutral wire ... press the test button ... display 3.6 mA

hooked the leakage clamp around the live ... press the test button ... display 5.9mA

I had the fluke 1653 plugged into the socket of the load side of the test unit ...

press the test button on the fluke meter ... the test unit trips in 16.3 mS

reset and press test button ... the test unit trips at 21mA

Remove the fluke plug top ... to make sure there was no load.

I carried out numerous earth to neutral touch tests ... every single time it tripped the earth leakage unit ... the display on the current leakage tester for each test ranged from ...
9.3mA
12mA
60 mA
95 mA


How do you create a 95 mA fault current with no load connected ?

The unit I used for the tests ...CLipsal 4 RCBM 216/30 10 kA

I connected my site earth leakage rig ... it is an EPC elpro 2 with 4 plugs fluch mounted to the sides of the enclosure ... to my horror ...it didnt trip when i touched the earth to neutral ... I then pressed the test button it didnt trip ... so i plugged in the fluke meter and tested ... it didnt trip ... Good thing i did the test ... I need to replace the earth leakage .. it is 20 years old and had a rough life ... no surprise it failed.

So in conclusion ... if i hadnt seen the video derek posted ... I personally would not have believed it was possible ... you live and learn.

38 years as a hands on construction/maintenance electrician in and around KZN ... I have personally never had an earth leakage unit not trip when i touched the earth to neutral .. unless it was faulty.

It would be interesting to see test results from sparkies in othe rparts of the country.

[ians]

Reading through some of the other comments I decided to try something ...

I decided to bridge the neutral and earth at the top of the earth leakage unit ...bingo ... the leakage current clamp display ... eeeish ... 305 mA.

With an earth wire bridged to the top of the earth leakage unit neutral terminal ... touched the an earth wire on the neutral at the bottom of the earth leakage unit ... instant trip.

[Derlyn]

So in conclusion ... if i hadnt seen the video derek posted ... I personally would not have believed it was possible ... you live and learn.

Hi Ian

I used the socket outlet just to facilitate the plug tester. After filming, I did short the earth bar and neutral with a piece of wire with the same result ( no tripping ).

The supply was taken from a dedicated plug in my workshop for testing earth leakages without tripping the houses one and irritating and upsetting mommy in the process.

Now, to be fair, I did this little experiment with the only 2 NEW units I had, a Chint which I filmed, that did NOT trip and a CBI unit that DID trip. Why ,I don't know.
The theory suggests that it should not trip.

My conclusion is that although the theory suggests that they should not trip, some of them do.
It would therefore not be correct to assume that the unit is faulty if it does not trip with an earth / neutral fault under no load.

Best to just use the plug tester and the test button.

The plot thickens.

Peace out .. Derek

[ians]

Hi Ian

I used the socket outlet just to facilitate the plug tester. After filming, I did short the earth bar and neutral with a piece of wire with the same result ( no tripping ).

The supply was taken from a dedicated plug in my workshop for testing earth leakages without tripping the houses one and irritating and upsetting mommy in the process.

Now, to be fair, I did this little experiment with the only 2 NEW units I had, a Chint which I filmed, that did NOT trip and a CBI unit that DID trip. Why ,I don't know.
The theory suggests that it should not trip.

My conclusion is that although the theory suggests that they should not trip, some of them do.
It would therefore not be correct to assume that the unit is faulty if it does not trip with an earth / neutral fault under no load.

Best to just use the plug tester and the test button.

The plot thickens.

Peace out .. Derek

I dont have any chint E/L units to test ... however i am certainly going to try one and an onesto unit (I have been using a lot of onesto products).

I would be interested to see what your leakage current is on your workbench.

By no means is the earth to neutral test a factor used to decide if a unit is to be replaced or not ... I have specialised fluke equipment (thermal imaging camera ... 435 power quality unit... 1653 insulation resitance testers ... etc) which is used to test product and services ... It still blows my mind that eThikweni arrive on site with a duspol tester to verify power and voltage issues .. I am a one man bussiness .. .they are the electricity supplier... its another joke ... I inform them of volt drops down to as low as 160 VAC and they test ... I have just downloaded a recording from an factory ... it has over 100 events logged ... mostly voltage drops ... its is destroying the VSD's in the machines.

[ians]

Chint is making arrangements to drop off a demo unit to test in my workshop ... lets see what happens.

[Derlyn]

Hi Ians

Just as an aside, I've replaced many faulty and burn't Onesto breakers on geyser circuits with Chint and have never gone back.

Peace out ... Derek

[ians]

Hi Ians

Just as an aside, I've replaced many faulty and burn't Onesto breakers on geyser circuits with Chint and have never gone back.

Peace out ... Derek

It has become a challenge for us to get chint products ... all the wholesalers use to carry chint ... but not anymore ... I dont why.

I have also only had good experiences using the product ... the price was right and i have no complaints about the quality for a product in the price range ... I used CBI for many many years ... but the price and quality just doesnt cut it anymore.

I had a 60 amp contactor coil burn out after many years of service ... but considering the power issues we experience in and around the Davenport in Durban ... I am not surprised ... with voltages dropping as low as 160 VAC ... massive surges which have resulted in over R200 k in blown equipment ...260 VAC spikes ... nothing will last.

i hope to see Chint products back on the shelves in the near future ... we might even get lucky and see the chint single RCBO on the shelves.