Nuisance E/L tripping only @ loadshedding

[joshthejew]

Hey guys.

New week, but still having the same problem at a house near the sea.
The E/L always trips when Eskom comes back on after loadshedding. Just to test, i replaced the E/L with a new cbi, split a circuit that was carrying too much load, i have checked all the connections in the DB.

I try causing a trip by switching off their double pole mains and flick it back up, but it doesnt trip. I dont want to waste the time there so i gave the owner instructions to narrow down where the problem lies by switching off all circuits on earth leakage when power is off, and checking if the E/L has tripped. if not, then we know that the problem is in one of those circuits. (Ive marked the specific cb's to switch off)

What i wanted to know is are there any other extraneous tests that i have overlooked to help me with this.

Thanks

[cje]

Hi Josh, uncanny that! I had exactly the same scenario...changed the ELR etc etc...to no avail initially..although it was an old Elpro one so having changed it seemed to stabilise. It may have something to do with the high in rush current at point of re-energising..but there are more able folk with qualified technical reasons out there im sure!

[AndyD]

Possibly a voltage spike when the power is restored. If there was a brief spike it would be conducted to earth by surge arrestors in a power supply or an appliance and the RCD could see this as a fault. The earth is functional as well as protective but a 30mA RCD that's supplying the entire installation isn't going to cut much slack if a surge arrestor clamping voltage is exceeded on top of possibly considerable standing background leakage.

..........I try causing a trip by switching off their double pole mains and flick it back up, but it doesnt trip........

If you switch L+N together you're more likely to cause an RCD to trip due to N-E capacitive leakage than if you just switch the live.

**Edit**

Maybe have a look at this, it might give you some clues;

[joshthejew]

Yea i'm going to have to take a look @ those that might have surge arrestor protection in one of the appliances. the owner runs a home gym, so rowing machines, tredamills are all there. but we never found a fault with them really. But might be the problem. thank you guys very much. will let you know the outcome.

[joshthejew]

Oh and thanks Andy for that piece on RCD's. Very useful

[SeanM]

Greetings All

I have a customer that has three phase to his property and three separate earth leakages every time there is load shedding two of these earth leakages trip when the power is switched off?

No tripping on switch on

I suspect that it have to do with Eskom's star point on there transformer.

[GCE]

Hi

We had same type problem and as Andy has said above , surge arrestors in equipment .
We found numerous plug top type surge arrestors on the circuit - We already had decent surge arrestors on the incomers and so we changed the plug tops and did not have further problems