[Question] Earth leakage problem

[Philani]

Hi guys
I have just encountered the following problem.

The earth leakage trips when test button is pressed. The earth leakage tester is plugged on the socket outlet and the 3 LED indicators light up to show that the connections are OK, but when the knob is turned to 30mA, the earth leakage does not trip.
Can someone explain what could be the problem here?

[Leecatt]

Your earth leakage tester is faulty?

Sent from my SM-A705FN using Tapatalk

[AndyD]

High earth impedance at the socket maybe?

Those plug in socket testers are notoriously misleading and inaccurate unless you buy an advanced one like this. http://www.socketandsee.co.uk/socket...et-tester.html

[Philani]

Thanks guys, I think a different type of EL tester would be a good idea.
It just that I have been using it all the time and I have never had any problems with it.

[Derlyn]

Check your supply voltage.

If you are using a Top Tronic TEL1TLB tester, it will not trip the earth leakage relay if the supply voltage is less than 213 volts.

Have you checked that the socket outlet has actually been wired through the earth leakage ?


Derek

[SeanM]

Greetings

Is that circuit wired through the earth leakage?

[Leecatt]

Greetings

Is that circuit wired through the earth leakage?

Very good point

Sent from my SM-A705FN using Tapatalk

[Philani]

The supply voltage is healthy, measured value is 236V and the earth leakage has been used as a main switch. All the circuits are connected with the earth leakage from one neutral bar.

[ians]

Plug in the earth leakage tester...you said all 3 lights are on... now switch off the earth leakage unit and see if the 3 lights on the plug tester switch off... they should go off... if not you have a wring problem.

Test the voltage:

live - neutral = 236 v
live to earth = should be the same (236 v) or about 1-2 volt different
earth - neutral = should be around less than 5 volts

do a loop impedance test at the socket outlet ...if the the result is within the required limit ...the plug is wired to the earth leakage unit then ...replace the earth leakage unit.

[Derlyn]

The supply voltage is healthy, measured value is 236V and the earth leakage has been used as a main switch. All the circuits are connected with the earth leakage from one neutral bar.

Easy.

Try another tester. If it works, replace the tester.

If same problem, replace the earth leakage relay.

Process of elimination with only 2 possible outcomes ( all others have already been eliminated )

Derek

[ians]

By the way we are assuming that you are a qualified electrician ...you use your test equipment on a daily basis ...your test equipment is calibrated as required and you have had suitable training on the use of the equipment?

[Philani]

Your assumption is very true. I am a qualified installation electrician but I have not been in the field for a long time as some of you have been. So my experiences are very limited and I believe from you guys there is a lot I can learn.

Any way I have checked the EL tester from another installation and is working perfectly.
Now, there something else I have discovered on that faulty earth leakage installation. When I perform the loop impedance and pscc test on the DB before the earth leakage, the readings i obtain are 265 ohms and 0.9 A (not kA) respectively. This is not making any sense to me. Any I deas?

[Derlyn]

Couple of questions.

1. Is the DB supplied directly from Supply Authority or is it a sub DB ?

2. If supplied from Supply Authority, is it overhead or underground supply ?

3. Is there an earth supplied by Supply Authority or not ? ie. 2 wire or three wire supply.
This might sound like a strange question, but I know of whole suburbs and settlements where earths are not supplied by Supply Authority.

4. Hit in an earth spike. Connect to earth bar in DB using 10mm wire and redo test.

[Philani]

This is the main DB fed from a 60A breaker installed inside a box mounted on the wall outside.
The supply system is underground and has an earth provided.
I am not sure if the earth in this box mounted on the wall outside is from the supply authority or not.

[Derlyn]

Somehow I think you should get an electrician to come and find the fault .....