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Author Topic: Can two electric meters run off one supply?  (Read 5389 times)

Offline semmyroundel

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Can two electric meters run off one supply?
« on: 20/03/2014 14:11:39 »
Hi all, this forum looks really interesting, being a heating engineer/plumber of 28 years I hope I've got something to offer, in the meantime....
I've been receiving two lots of bills from the electric company, one for a meter that controlled storage heaters, and one from a meter that did all the 'normal' tariff electricity.
The two were completely separately wired, that is to say, between 11pm and 7am one of the meters would read electricity consumed ONLY by the equipment connected to it (not ECONOMY SEVEN, for those in the UK), eventually, all those sockets were disconnected as I put gas heating in. Fearing that I would pay the rental for two meters, I had an electrician come in and install one consumer unit (fuse box).
Now, I continued to get bills for the meter that was disconnected (so I thought) and I found that he'd wired the tails in parallel to the other meter, so that they both connected to the same consumer unit so that in theory, at night, when the timer switched on allowing current to pass through the off-peak meter, BOTH meters were supplying the consumer unit with electricity, get my drift?
Here's where the theories come in: one electrician said that meters are current-operated and therefore both can't run simultaneously, another said that they somehow share the current (some going through one meter and one through another) I could understand if both meters were induction based as in both motors turning more slowly, but one is electronic. A third said that current will take the shortest path, and even if it's been supplied from two sources, only one would be used (he also said to do a resistance check on the tails to see if this was the case).
Now I'm puzzled, please help, it's a long time since I did my electricians course and I don't remember all the equations.


 

Offline syhprum

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Re: Can two electric meters run off one supply?
« Reply #1 on: 20/03/2014 17:15:46 »
I see little technical problem here but probably a legal one with the current sensing part of the regular meter partially bypassed by the current sensing portion of the old meter it will not be reading correctly so you will be undercharged for the power you use.
I would advise you to notify the supply company and explain how this situation arose before they take any action.   
 

Offline CliffordK

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Re: Can two electric meters run off one supply?
« Reply #2 on: 20/03/2014 17:47:49 »
I assume both meters are running in parallel.



That would be an odd setup, although it should work just fine as long as both meters are being read by the power company.

The basic electrical equation you would use is: V=IR.  Look up parallel resistor circuits.  If both circuits are identical, then the current would be spread equally between the two.  If one has higher resistance than the other (longer, smaller wires, more resistance in the meter, etc), then the split would be unequal.

Here in the USA, one spends about $10 per meter per month.  So, having two meters would cost you extra.

If you don't need the two meters, call the power company and get the second meter pulled, then call your electrician back to get the excess wiring cut out of the circuit.
« Last Edit: 20/03/2014 17:57:48 by CliffordK »
 

Offline syhprum

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Re: Can two electric meters run off one supply?
« Reply #3 on: 20/03/2014 19:09:43 »
if both meters are being read you would still be getting some of your daytime power at the night power rate (the proportion would depend on the relative impedance of the current measuring circuits) which would not please the power company but if you are paying $10.00 a month for an extra meter they are probably not losing out !
I wonder if they are truly working in parallel perhaps the electrician wired some of the outlets of the new distribution box to one meter and others to the night rate meter which would still be slightly illegal if there in no time switch in the circuit.
If you can get details of the new distribution box it might be possible to get a circuit diagram to see if it is possible to supply different outlets from two different meters
.
« Last Edit: 20/03/2014 20:37:46 by syhprum »
 

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Re: Can two electric meters run off one supply?
« Reply #3 on: 20/03/2014 19:09:43 »

 

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