anyone recommend an earth leakage clamp meter ?

[petehall347]

ok just collected the clamp meter so will do some checking soon . first off os check leakage at the tails of the rcd .this will give me combined leakage as it stands now .

[petehall347]

had a quick look today and getting leakage big style . i need to start isolating everything really and check again .. the main ground has about 60ma through it . the rcd tails are showing 28ma so should really be tripping . am thinking there is a bad neutral connection to find . might even be dc on the line blinding the rcd .. this is one of them jobs that can take 5 mins or 5 hours to sort out , ok the clamp meter i am not very impressed with it as the reading changes quite a bit depending on wire position . the instructions say wire in centre of clamp .well that is impractical really .
on a similar note i just watched this video .sorry that its on facebook .. https://www.facebook.com/watch/?v=496148411919080

[redwire]

same vid is on youtube, FB total garbage Diverted Neutral Current - SparkyNinja
Installation leakage they say 4.3A is normal on incoming ground?! Yeesh.

60mA is quite high, it should be making heat somewhere? I would suspect the water heater or boiler assuming it's electric, heating element corroded getting wet. I think Line gets switched by the thermostat though, so it should not be a constant reading. Something will be bubbling. 6:30AM/PM I thought it's an appliance for breakfast/dinner.
The clamp-meter jaws can do some math, if you put all the power conductors in the jaws, any net flow will display. Just like the RCD principle I think, Line and Neutral in the CT and any difference must be ground current.

[petehall347]

its not tripped for a few days . i first need to look at the rcd to see if its faulty and staying latched . the meter is telling me it should trip . will obtain a tester or find a 6.8k resistor .

[CapLeaker]

petehall347 while your at it, post some pics. Man, I am getting curious on where this comes from.

[petehall347]

latest findings today up till now . there are 2 of us that run off the supply from the rcd in question and we are about 120 metres maybe more from the supply .there is about 5ma leakage each measured across live neutral so that's good . now where it gets interesting is we both have local ground rods and both are carrying around 30ma each after isolating our consumer units so its looking like the problem is closer to source .our neutral to grounds measure about 1.2v so can call that good .

[petehall347]

found something now and made it better . turned out the main earth rod that connects the supply neutral had corroded away so we no longer had that earth until i knocked it into the ground and watered it . now its just showing combined leakage of about 50 to 60ma . and the 2 other ground rods about 5ma as expected .
so its as i expected my supply and the other with ground rod was providing the earth .
plus i found the main cables were chewed by rats exposing the bare wires so coated them with conformal coating which lowered the leakage somewhat .
still not figured why the 30ma rcd is staying on with 30ma leakage . only cure i reckon is fit a 100ma rcd then it will be sorted .

[stj]

how do rats chew the cables? isnt it concentric?

[redwire]

When the main earth rod went open, if there ever was a (distribution system) ground fault, high current would get pulled from your local ground plus any appliance with metal piping.
It's possible that overload made a ground wire/connection go open circuit. Look for an open ground resulting from the main ground failing.

[petehall347]

how do rats chew the cables? isnt it concentric?

they chew anything except anything coated in waste engine oil .

[CapLeaker]

Aren't all these ground rods connected directly together?

[petehall347]

Aren't all these ground rods connected directly together?

yes they connect together through the power cables .

[CapLeaker]

Oyyy! This story is getting better by each post! The ground rods supposed to be connected together via a ground cable, not through the power cables! Maybe explain why each unit has a separate ground rod, while the main power entrance has one?
I've got multiple ground plates in 3 different locations around my house that are all joined together. Why? I didn't like the zapping during lightning storms. Since I did that 20 years ago, no more zapping going on inside my radios.
Extra ground rods that aren't connected through an extra large diameter ground cable to them selves is a no no!
If you measure at each ground rod, chances are good, every rod has different readings. That shouldn't be.

[petehall347]

ah i see whats been done now . its combined tns and tt which shouldn't be done . however it did provide grounding to the main system when the incoming ground neutral became detached from the ground . thinking best way of doing the mobile homes is having their own ground rods independent of the main supply by disconnecting the supply ground wires at the mobile homes supply and just using ground rods . TT .
this is how it stands but water pipe is ground rod . there is no metal water pipes on site .

[petehall347]

cant edit last post but that diagram is not exact same as here it has ground rod at entry point

[stj]

LOL - that water pipe!
i went to a flat once that could zap you from the taps!!!
inductive coupling because the water company had replaced the old pipe with a poly one!!
i had to go into the basement and reconfigure the earthing from the water line to the incomming power shielding.
got some great sparks when i connected it!

[CapLeaker]

Yeah, thanks but no thanks. Install proper grounding. Better than ground rods are ground plates. Not all water pipe is made out of metal either. I know places where all inside is metal piping. However the feed from the main water line on the street to the house is PVC. Do it right.

[petehall347]

Yeah, thanks but no thanks. Install proper grounding. Better than ground rods are ground plates. Not all water pipe is made out of metal either. I know places where all inside is metal piping. However the feed from the main water line on the street to the house is PVC. Do it right.

yes i have seen water pipe like that here . earth bonding to them too .

[redwire]

Also consider the natural gas and sewage pipes, if they are metal outside the house. You can get some weird paths for ground currents by appliances that cross-connect. CATV as well.
Here a (hot galvanized zinc) ground-plate I have seen embedded inside concrete foundation walls.
I've used copper ground rods but sometimes you can put one in and it's high impedance and you have to move to another spot. Depends on the soil and rock. Frequently the wire connection to the ground rod corrodes and goes bad with age.

I thought it's been really wet over there?

[CapLeaker]

yes i have seen water pipe like that here . earth bonding to them too .

Well… that's creating grounding issues, A ground on a plastic pipe is worth zero. My CATV cable is grounded to the power entrance ground before it goes to the modem. Proper earth ground is your friend, Keep in mind your soil or rocks / ledge etc. As ground conductivity gets worse, you need more ground plates,