200 ma on earth

[NICK C SPARKS]

Just a bit puzzled by this one was called out because rcd tripping, but only once or twice a month put my earth leakage meter on earth cable and was getting 200 ma
so started to isolate each circuit to narrow the fault to 1 circuit. The 200ma never altered then turned off the main switch but still 200 ma .i was just wondering if the digital suppliers meter could be drawing a supply up the neutral and leaking to earth at the transformer and sending it up the earth . This is a tns system
any help cos been doing a lot of head scratching

 

[mayfair]

next door ? just an idea

 

[rallyandy]

sounds like supply cable might be damaged , causing leakage ? ,, just a thought , give DNO a ring

 

[NICK C SPARKS]

Yes worth a try but had them out on another job at a block of offices (lights flickering) when large load applied said it was on our side even did a ins res test in front of them still would ent have it until half the street went off the next day and had to start digging road up to repair the n in the supply cable cheer

 

[rallyandy]

Yes worth a try but had them out on another job at a block of offices (lights flickering) when large load applied said it was on our side even did a ins res test in front of them still would ent have it until half the street went off the next day and had to start digging road up to repair the n in the supply cable cheer

if you have exhausted all other options with testing customer side and as Mayfair says there is definitely no source of connection or leakage transferring from next door, I think you will have to ring DNO. is it possible to do a quick test on next doors supply as some incomers split between 2 houses ?, even try another neighbours house, if u still get same readings they will have to come out. have you tried using a different meter, you never know lol

 

[SimpleSimon]

Agree with the above, would be a safe idea to check the neighbours supply. You never know you may knock on the door explain why your there and they turn around and go "Thats funny we get the same thing", and so do the other house and the other until you find a leakage on the transformer thats feeding the street!! Never know.

 

[nickblake]

Slap a Ze test on it three wire see what the Ze is if there is a neutral problem it should show up ,flickering lights especially on a tncs is normally cause by a faulty neutral and can be dangerouse and expensive total loss of the neutral on a tncs can slap 400 volts over the loads so its by by sensitive electronics , give them a call and get them to test it

 

[sparkinlee]

Just a bit puzzled by this one was called out because rcd tripping, but only once or twice a month put my earth leakage meter on earth cable and was getting 200 ma
so started to isolate each circuit to narrow the fault to 1 circuit. The 200ma never altered then turned off the main switch but still 200 ma .i was just wondering if the digital suppliers meter could be drawing a supply up the neutral and leaking to earth at the transformer and sending it up the earth . This is a tns system
any help cos been doing a lot of head scratching

Have you solved this? Would be interested to know, as I'm a bit baffled.

So you've got a 200mA current in the earth wire even with the ccu main switch off... there must be a voltage source to be producing the current, and so it can't be the installation if that is switched off. You suggest it may be a leak to earth in the meter, but all the meters I've worked on don't have an earth connection and so could not directly leak to earth.

Have you traced where the current is coming from? Maybe disconnect the gas & water bonding and see if it's still present, or disconnect individual circuit cpcs from the earth bar...

Is there a PV system on the roof which could be providing the necessary voltage source?

And finally (I expect that you've thought of this already, but just to mention it) have you proved you meter?

I'm interested to know what the answer is!

 

[NICK C SPARKS]

To answer sparkinlee without pulling the main fuse i still have l and n to the digital kwh meter (suppliers) which draws current if there is a fault in the suppliers cable could this be the load coming back up the earth or more likely to be a load from next door ethier way still on rec side
am going back tomz to check next door so should have a definate answer done the other tests listed in threads just hope can put this one to bed after tomz
cheers for all the advice guys just comfirms things and clears your mind that its not something more will post more if not solved

 

[rallyandy]

To answer sparkinlee without pulling the main fuse i still have l and n to the digital kwh meter (suppliers) which draws current if there is a fault in the suppliers cable could this be the load coming back up the earth or more likely to be a load from next door ethier way still on rec side
am going back tomz to check next door so should have a definate answer done the other tests listed in threads just hope can put this one to bed after tomz
cheers for all the advice guys just comfirms things and clears your mind that its not something more will post more if not solved

Hi Nick as sparkinlee says please what you find was wrong once solved i am interested as well many thanks