Electricity meter running backwards!!!

[m_d_allen]

Hi All,

We had a new elec bill yesterday. Their estimated was way off the actual reading. On further investigation our meter is now running backwards!! We dont have solar power or any other elecricity generating means.

About 18 months ago we had a new consumer unit fitted with new tails to the meter from the main incoming fuse.

I wondered whether this had been wired incorrectly. Looking at the cabling at the bottom of the meter left to right the 4 wires run as follows; (from consumer unit) +ve, -ve, (from main fuse) -ve, +ve. Is this correct? Anybody any ideas what is going on? Would mis wiring a meter make it run backwards even?

They are coming to have a look in a fortnight but just wondered whether anybody has any ideas? Its very wierd...

[TheScullster]

wrote

I hope you are billing your electric company for the power you are obviously putting back into the grid :).

Phil

[Tournifreak]

It's been wired up wrong.

Should be: Live (In) Neutral (In) Neutral (Out) Live (out)

But, I'm amazed it runs backwards. Almost all manufacturers have a mechanism to prevent that happening, as a deterrent against fraud.

Jon.

[george (dicegeorge)]

which meter is it from which company... i want one!

[g]

Tournifreak wrote:

[Tournifreak]

Certainly not one of ours! (Actaris)

Presumably a mechanical meter too, which I would have thought is unusual for a new-fit these days, in the UK.

Jon.

[Osprey]

It used to be a scam to reverse leads to make them run backwards - then they out a ratchet mechanism in place to prevent this, so surprised it's doing that.

Other scam used to be to place a magnet on side of meter to slow down the horizontal disc .... but then they changed to Aluminium to beat the dodge.

[mark]

Do they prevent top posting then?

mark

[The Medway Handyman]

There was a distinctly dodgy gadget being sold around 20 years ago (maybe longer). It was a black box with 2 insulated leads coming out of it - rather like the probes on a multi meter.

My mate had one on his factory. The probes were pushed up next to the cables (don't know which ones) & the meter did run backwards. Got the impression the black box contained a large coil of copper wire?

[Ed Sirett]

I agree with the connection order.

[Brass Monkey]

If attempting to minimise leccy costs, don't do what an aquaintance did. He reckoned there was a small hole (or he made a small hole) underneath the hands so that he could tweak the pointers to a lesser value. Problem was, one of the hands came off its spindle :D

[cynic]

'Twas usually a wall-wart supplying a current to the two probes at a low voltage. Pushing the probes up alongside the outer two tails made contact with the meter Lin and Lout then the wall wart injected a current into the current coil of the meter. If you got them wrong way round the meter ran faster. Greed was the usual tell-tale when consumption suddenly dropped to rididiculously low levels or even became negative if the wind-back exceeded the disc wind-forward of normal usage. The other tell-tale was a 13A socket newly installed next to the meter to power the cheatbox

Modern meters are modified to stop the scam working although some utility companies re-use old recalibrated kit which may give you the opportunity to cheat in the above manner

[ARWadsworth]

They were called "Meter Beaters" in Yorkshire.

They did work.

Adam

[The Medway Handyman]

I don't recall it being pluged in anywhere, didn't seem to need any external power.

[Tournifreak]

The next generation of smart meters that will be installed in the UK in the next 5 years or so are a *lot* harder to beat. They have hall sensors to detect if a magnet is used near them. They can detect reverse current, bypass conditions. The readings are taken via GPRS or PLC. Many also have contactors built-in so that the supplier can cut you off remotely if you don't pay your bill on time.

Jon.

[Dave Liquorice]

The only false reading I've ever had taken by a meter reader was one taken electronically by the reader holding his gismo up to the circular indentation on the meter.

I can see that being fun to sort out when (not if) a typo on data entry of meter number to account association means that some innocent person gets cut off. True computers never lie, but garbage in garbage out. The utility companies barely manage to administer migration from one supplier to another with anything approaching acceptable error levels.

[Andy Dingley]

Nope, trad mechanical meters just don't care (unless you get inside the meter case and swap some of the internal wiring).

The "gadget" was an inductor that messed with the power factor of the load, thus confusing the meter. It didn't make them go backwards, but it did slow them down. Most of these were made up in little back street electrical shops (like City Surplus in Liverpool) then sold to their end users. As the end user often isn't the sharpest square wave on the 'scope, they were freqently caught by meter reader's inspection, then persuaded to name the supplier to lighten their own fine.

Mechanical meters have also been deliberately resistant to running backwards (ratchets etc.) since the '20s at least - there are many patent mechanisms for this.

I don't believe this story of "swapped wires made the meter reverse". Certainly not from an OP talking of positive and negative connections.

[Tournifreak]

That shouldn't happen! The encoding system should pretty much guarantee error-free readings. (CRCs etc) I can only think he read the wrong register or something. There's a lot of data stored by meters these days, and it's easy to pull out the wrong field.

Yes, I know. Scary isn't it? If you think billing is complicated now though...man you should see some of the stuff the utilities are asking for in the next generation. I can see a time when everyone has unique tarrifs. You will be charged different rates at different times of day, depending on how much power you've used in the last few hours, or days. Readings are taken every few seconds and stored, then transmitted back to the utility every few hours. Making comparisons between suppliers will becoem impossible. (Not just rather difficult as it is at present.)

Jon.

[cynic]

The little wheel (disc) is acted upon by the product of the voltage coil and the current coil alternating magnetic fields. It did make the disc run slow when I saw one of these things some years ago and tried it on an old mechanical kWh meter which I had on stock at the time.

If it had not worked there would have been nothing for the RDOs to gain by fitting solid block input connectors or the current range of sleeves to their meters. The mere fact they did at some cost should tell you something.

[The Medway Handyman]

Now you mention it, thats what happened. You could see the meter slow down - it was a long time ago :-)

[marpate1]

But, was it an inductor? The load in a house is largely inductive anyway so by adding more inductive load should increase the meter rate. I would have expected that the device was actually a capacitor to perform power factor correction and correct the phase relationship between the voltage and current. (I think that it used to be that the meter rate was determined by the phase relationship of voltage and current - the more that current lag the voltage, the faster it spins). A larger capacitance should be able to make the meter reverse but it would be a huge capacitor!

Never seen any of this in action ... just recalling power factor correction from college some 20 odd years ago :)