Earth leakage on MEC during 'black-out'

[Deleted member 72666]

I was recently playing with my Amecal leakage current tester and found approx. 2mA when clamped around both tails at home, I put this down to the various tv's and game consoles on at the time, but when I clamped the MEC at the same time I found a fluctuating leakage current of anything between 200 and 300mA. The house is only about 50mtrs from the sub station (TNS btw and a Ze of 0.2 ohms) This has been bothering me for a couple of weeks now but last night we (the whole village) suffered a power outage for a couple of hours, ideal time me thinks for another test on the MEC, this time I measured a fluctuating current between 10 to 35mA and nothing on the tails (no surprise there!). I'm a little baffled now, could it be a pv system that is causing the leakage from a discharging inverter capacitor or perhaps the pv system generating as it was a full moon last night (not sure if moonlight would be strong enough to do this though.) Has anyone come across this situation before and found where the leakage is from.
Oh, I forgot to mention I disconnected the earth bonding to both gas and water and the leakage dropped to zero but went back up when either was reconnected. No voltage was present between the MEC and earth bonding conductors when separated which makes me think either it's 'ghost currents' (but never ever heard of this lol) or I've got myself a carp leakage tester or should I be worried and get the DNO involved?
Sorry for such a long post but I've tried to give as much info as poss.

 

[PEG]

Hi dude,what type of property is it? Also,has everybody got the same type of supply,are there any PV installations,and did you get any PEFC and PSSC results? Also,fair play to you for messing with your tester whilst everybody else is typing pap on faceboob :conehead:

 

[Deleted member 72666]

End terrace. Not sure if they have all got the same now as over the last 5 years 8 of my neighbours have had their supply cables replace due to loss of supply so they may have been pme'd but can't be sure. PEFC 1.1kA and PSSC 0.8kA.

 

[guest119]

Is your water pipe lead/copper or plastic?

 

[Deleted member 72666]

Is your water pipe lead/copper or plastic?

A mixture of all 3! Water pipe comes in plastic for about 1 metre then approx. 1 metre of lead then the rest in copper. Bond is on the lead pipe btw.

 

[Lucien Nunes]

So you've got a few hundred mA flowing between one big network of conductors and another, when they are solidly connected together, but only tens of mA when the supply is off. Doesn't sound terribly surprising or worrying to me. If it were 100 times higher I'd start to pay closer attention.

 

[Deleted member 72666]

Is there a possibility that this leakage current could increase dramatically and if so under what conditions?

 

[Lucien Nunes]

But it's not leakage current, that was only 2mA when you clamped the tails. The rest of it is just circulating ground network current, driven by negligible voltage over low external impedances, as per your test with the voltmeter with the bonding open-circuit.

 

[Deleted member 72666]

But it's not leakage current, that was only 2mA when you clamped the tails. The rest of it is just circulating ground network current, driven by negligible voltage over low external impedances, as per your test with the voltmeter with the bonding open-circuit.

That's exactly the sort of explanation I was looking for, thanks!