Hi All,

So have fairly newish system running now for the last 5ish months. And with the recent increased frequency of load shedding a very odd thing started happening.

When the powers come back online, the earth leakage trips. This never happened before the system was installed. Trying to figure where potentially things are going wrong. So has anyone else experienced this?

Thanks
G

Check for bad  Earth leakage, neutral split,  appliance leakage  of earth  neutral bind at supply.

The Earth leakage only trip with imbalance between live and neutral thru earth leakage.  

Check  inverter settings for appliance or UPS, try appliance setting and see if this help.

In some cases installing an RCD with anti-nuisance tripping solves the problem. Hagar and ABB work well.

 

What type of earth leakage breaker is it? If it's an 'AC' type you could be looking for AC leakage with a DC component to it.

As above, earth leakage breakers are known to sometimes nuisance trip when power is restored. They can be sensitive to downstream and upstream harmonics and phase angle disturbances which can occur depending on the type of load connected.

0 & 180 degree ramp test the earth leakage and check trip times at .5x, 1x and 5x. Do an IR test with L+N combined and earth but also test global leakage current as a live test with a clamp meter around the L+N on the earth leakage load side. If these tests give good results then you can add an extra earth leakage breaker and split the circuits between the two assuming there's space or alternatively try a different brand of earth leakage breaker.

43 minutes ago, Marv said:

 

What type of earth leakage breaker is it? If it's an 'AC' type you could be looking for AC leakage with a DC component to it.

As above, earth leakage breakers are known to sometimes nuisance trip when power is restored. They can be sensitive to downstream and upstream harmonics and phase angle disturbances which can occur depending on the type of load connected.

0 & 180 degree ramp test the earth leakage and check trip times at .5x, 1x and 5x. Do an IR test with L+N combined and earth but also test global leakage current as a live test with a clamp meter around the L+N on the earth leakage load side. If these tests give good results then you can add an extra earth leakage breaker and split the circuits between the two assuming there's space or alternatively try a different brand of earth leakage breaker.

@grant.cpt I assume by 'system' you have an inverter. What is the model and make of your inverter. ? Is it offgrid or grid tie?

Is the grid side (upstream) of your inverter going through an ELD .?

Also , is your load side of your inverter also connected to an ELD?

 

 

15 hours ago, grant.cpt said:

When the powers come back online, the earth leakage trips.

Only once? or do you have earth leakage tripping at odd times, when on commercial power?

Depending on the connections and how things are wired, the neutral or the earth on the main supply side (Eskom/CT municipality) may be disconnected/have some resistance...

Apparently in recent times quite a few people in the greater JHB area have had neutral connection disconnected/burned off at the municipal supply side...

 

4 hours ago, Kalahari Meerkat said:

Only once? or do you have earth leakage tripping at odd times, when on commercial power?

Depending on the connections and how things are wired, the neutral or the earth on the main supply side (Eskom/CT municipality) may be disconnected/have some resistance...

Apparently in recent times quite a few people in the greater JHB area have had neutral connection disconnected/burned off at the municipal supply side...

 

I've heard this before , my solution is to have a voltage monitor on the grid input , and a timer running for 20 seconds while in a certain window of forgiveness  190vac to 245vac , and then switch the output on. However it's not cheap ,it requires half-decent contactor  , and there are no commercial product available either. 

BTW we use this technique on railways control rooms , and where there are 3 phase , we also check correct  phase rotation within the test window.

 

EDIT : ok this doesn't help the situation where neatral is floating above earth.

Edited May 11, 20224 yr by BritishRacingGreen

On 2022/05/10 at 7:57 PM, grant.cpt said:

When the powers come back online, the earth leakage trips. This never happened before the system was installed. Trying to figure where potentially things are going wrong. So has anyone else experienced this?

How old is your actual earth leakage breaker?

I had something similar a while ago, when my earth would trip randomly. Hunted around like a mad man, trying to find the root cause. Eventually my electrician replaced my earth leakage breaker (which was probably almost 10 years old) with a new one - and problem solved. He told me that as these things get older, they sometimes get more sensitive and start tripping

On 2022/05/11 at 10:38 AM, BritishRacingGreen said:

@grant.cpt I assume by 'system' you have an inverter. What is the model and make of your inverter. ? Is it offgrid or grid tie?

Is the grid side (upstream) of your inverter going through an ELD .?

Also , is your load side of your inverter also connected to an ELD?

 

 

Yes, system = Inverter and it's an Axpert King 5KW
TBH, not sure I catch the ELD acronym. Would you mind explaining?

 

On 2022/05/11 at 11:19 AM, Kalahari Meerkat said:

Only once? or do you have earth leakage tripping at odd times, when on commercial power?

There has been one instance whereby the earth just tripped for now reason. This was with Eskom/Municipal supply not being interrupted and resumed.

 

11 hours ago, wolfandy said:

How old is your actual earth leakage breaker?

Oh it's pretty old (I think) it's an HEiNEMANN brand

Edited May 12, 20224 yr by grant.cpt

18 hours ago, grant.cpt said:

Oh it's pretty old (I think) it's an HEiNEMANN brand

😝

Before doing any other modifications to try and solve your problem, I would probably start by putting a new one in