# The Naked Scientists Forum

### Author Topic: Partially bypassed electricity meter? -pub debate!  (Read 47906 times)

#### james125

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##### Partially bypassed electricity meter? -pub debate!
« on: 26/08/2013 22:32:11 »
I know this site isn't going to condone stealing electricity and I'm not intending to either. Me and a few friends had a long debate in the pub over this and we're still unsure of the answer. So hence I'm asking it on here.

So the question; What would happen if you connected 2 wires (+ & -) from the mains supply to your fuse box by passing the electricity meter without disconnecting the original electricity box wires.

Surely it would be a simple question of the resistance of both sets of wires as to how much current goes though each? Presumably the electricity box has a small resistance so most of the current would go past the electricity box though the wires with least resistance? Unless of course the bypass wire was thin that it would heat up and increase in resistance in which case the bypassed current would be limited.

Me and my friends aren't great when it comes to electrical engineering. I have the presumption that this circuit would behave in the same way as a DC circuit, or does AC make a difference?

#### RD

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##### Re: Partially bypassed electricity meter? -pub debate!
« Reply #1 on: 26/08/2013 23:47:31 »
I know this site isn't going to condone stealing electricity ...

A death sentence can still be applied for fiddling with the electricity meter...

« Last Edit: 26/08/2013 23:49:56 by RD »

#### CliffordK

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##### Re: Partially bypassed electricity meter? -pub debate!
« Reply #2 on: 27/08/2013 01:08:29 »
The meter undoubtedly has some resistance.  However, many (all?) of the new meters use an induction ammeter which would have exceptionally low resistance.

Your wires (copper or aluminum) also have some resistance, so the wire size/path would make the biggest difference in the proportion of the current that follows each path.

There have been weed farms discovered due to steeling power from the grid.

#### evan_au

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##### Re: Partially bypassed electricity meter? -pub debate!
« Reply #3 on: 27/08/2013 11:10:15 »
I don't want to scare you, but which wire is "+" and which is "-" changes 100 times per second (120 times per second in some other countries)!

Nevertheless, the method you describe would work - provided you didn't connect the wire which is currently "+" to the wire which is currently "-". Then you blow a fuse that you can't replace. Also provided you don't connect the wires to yourself - then you might blow a heart that you can't replace.

Some people have tried this, only to have their house burn down because the electrical connections had a high resistance, got hot and set the rafters alight. The fire brigade detects the electrical hack after they turn off the power and extinguish the fire.

Fortunately, the electricity companies are on the lookout for things like this using manual procedures and software on their billing systems and often detect such hacking attacks before the house burns down. Modern electronic meters have detailed data collection that can be used to analyse the precise household consumption for suspicious patterns.

Many years ago I had a job designing electronic power meters, and we looked at a way to detect the meter being bypassed by inducing small currents in the mains supply, but I don't know if such techniques have been deployed in today's mass production electronic meters.

Do not try this! The electricity supply industry operates on very fine margins, and one person stealing electricity can wipe the income from an entire street. You will be "biting the hand that feeds you" - if the electricity doesn't bite you first!
« Last Edit: 27/08/2013 11:16:37 by evan_au »

#### snowyco

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##### Re: Partially bypassed electricity meter? -pub debate!
« Reply #4 on: 21/02/2014 17:18:56 »
I don't want to scare you, but which wire is "+" and which is "-" changes 100 times per second (120 times per second in some other countries)!

This claim is not factual.   For over 100 years,  for single phase:  US standard 110V household  and  UK standard 220V household alternating current systems   use   1 wire   as a neutral/ground and a  second wire  as the "hot".  The "hot" wire carries voltage that fluctuates/alternates between + and -     versus   a neutral/ground wire that is at zero (0 V).

The "hot" wire is the only one that has changing voltage (in a single phase electrical system).   Once you determine which wire is "hot",   that does not change,   regardless of whether the system is a 60 Hz US standard or 50 Hz UK standard.

The OP's question:   If you installed a jumper of equal size to the existing incoming and outgoing wires,  and the impedance (AC "resistance") of the meter is very low,  you would get slightly more current flowing through your jumper than the meter.      You could crudely calculate the relative differences by using Ohm's law ( V = IR  )   and  the total resistance for parallel resistors  ( 1/Rt = 1/R1 + 1/R2 + ... + 1/Rn ).
« Last Edit: 21/02/2014 17:21:39 by snowyco »

#### The Naked Scientists Forum

##### Re: Partially bypassed electricity meter? -pub debate!
« Reply #4 on: 21/02/2014 17:18:56 »