Will a magnet have an effect on an electric meter?

Is this a trick question? Electric meters have a magnet in them, so are you adding another magnet to the equation? Susu

The light co. have been on to that trick for years and meter designs have changed plus messing with their meter could mean jail time it is better just cut back on the power robbers you have in the house such as lights all those power supplies allover the house i have 6 just for phones plus 2 for cell ph. 2 moer for mini vacs 1for sond on the computer any tv that is not being used unplug or put on switchable outlet a tv is on even when you turn it off just to name a few oh yes 4 more for batt operated tools in garage

It could, yes. what exactly are you testing?

As Jim stated and sidelko stated, it can if you are adding one, as it can make the meter run backward or if the magnet is not strong enough, it can slow it down, therefore reducing your electric bill. As jim stated, this is highly illegal, it is considered grand larceny in many states. The reason many states consider it grand larceny is if they could not determine for sure the amount of energy you stole in a dollar amount. Many times they can figure it based upon previous usage and then get an average from that., By the way the significant change is usage is one of the things that the electric company first notices, because they have auditors who review accounts on either a monthly or quarterly basis. So if you know someone who is contemplating doing this, make sure that they are aware that they will eventually get caught, and depending on which state they live in, the penalties can be really severe. Here is what the penalties here in Texas are, just to give you a rough idea which depends upon how much the judge values the loss at (each state is different however).
Felony - 1st Degree - Fine up to $10,000 & or 5 to 99 years, 2nd Degree - Fine up to $10,000 & or 2 to 20 years, 3rd Degree - Fine up to $10,000 & or 2 to 10 years.
Hope this better explains it. Susu

It depends upon how the electric meter is made. If it is magnetically shield with some ferromagnetic material, than it will bypass all the magnetic lines of force through it. In this case there will be no effect of the magnet on the electric meter. But if the meter is not properly magnetically shield then the magnet will interfere the magnetic field of the meter's internal magnet. In this case the electric meter will not work properly.