Fault Causing Increased Meter Reading?

[coolsparx]

I have a customer who has seen a massive rise in unit usage, then a bit of nuciance tripping. I went out to investigate & discovered a low IR (about 0.1M) on one of the socket circuits. I disconnected the faulty section to get the power back on & will return another day to bypass the faulty section under the concrete floor to reconnect the rest of the sockets. He didn’t know his previous useage but for a while it has been really high about 20 units every 12 hours. He has called today to say his usage has dropped to under half that. He has no electric water or room heating.

Has anyone else cone across this kinds of usage increase due to a fault?

 

[davesparks]

Have you calculated the current which flowed through the fault and thus the power consumed by it?

If it is a 0.1megohms then I make the current 0.0024A and the energy consumption one unit per 2000 hours.

What was tripping? If it was a 30mA RCD then it should be obvious the fault current was generally less than 0.03A

For the fault to use 20 units in 12 hours it would have to be dissipating around 1.6kW as heat, so I'd imagine someone would have noticed the heat or even fire started by this!

 

[coolsparx]

Have you calculated the current which flowed through the fault and thus the power consumed by it?

If it is a 0.1megohms then I make the current 0.0024A and the energy consumption one unit per 2000 hours.

What was tripping? If it was a 30mA RCD then it should be obvious the fault current was generally less than 0.03A

For the fault to use 20 units in 12 hours it would have to be dissipating around 1.6kW as heat, so I'd imagine someone would have noticed the heat or even fire started by this!

It didn’t seem that plausible, hence me asking on here. Maybe disconnecting some sockets has prevented the MIL plugging in an electric heater?

 

[static zap]

Supplementing some-one else's Heating / Growing more noticeable in winter.
Is reading for a timer currently in off state !

 

[coolsparx]

Supplementing some-one else's Heating / Growing more noticeable in winter.
Is reading for a timer currently in off state !

The boiler is an oil combi & there is no immersion heater, I did see 1 freestanding 2kW convector heater but nothing else. Once I reconnect the sockets, I will get him to continue to monitor his usage. I do wonder if his M-I-L is using the convector heater in the conservatory or in the dog kennels, however it is difficult to question a customer once they have said they don't use any heaters!

 

[davesparks]

I did see 1 freestanding 2kW convector heater but nothing else.

however it is difficult to question a customer once they have said they don't use any heaters!

???

 

[coolsparx]

???

He claimed it wasn't used & I didn't see it actually plugged in, so I couldn't call him a liar.

 

[Top Cat]

I was called to a house that the guy said his bills were horrendous, after checking everything out I found in the lot a 2 KW heater plugged in! When I said about it he said Oh ---- I plugged that in two years ago when it was freezing to protect the pipes in the loft!

 

[DjMadness]

Hi,

Perhaps the faulty area was encountering a non bolted short circuit: considering a single phase, 2wires circuitry for the sockets, under the concrete the L and N are meeting together through a large conducting body (metallic chassis or so) reflecting in heat that the user hasn't noticed for the chassis having a large mass, and being buried under the ground


Dj

 

[Bobster]

Hi,

Perhaps the faulty area was encountering a non bolted short circuit: considering a single phase, 2wires circuitry for the sockets, under the concrete the L and N are meeting together through a large conducting body (metallic chassis or so) reflecting in heat that the user hasn't noticed for the chassis having a large mass, and being buried under the ground


Dj

This would create a fault of negligible impedance and cause the circuit protection to operate.

This isn't the issue.