Different Methods of Meter Tampering
& its Effect on Meter Registration
Tampering the body seals affixed to the meter or replacing the original seals with fake seals
It is done with the purpose to manipulate the internal meter mechanism in order to reduce actual registration to the extent that depends on the nature of tampering
TYPES OF METER TAMPERING THAT INVOLVES BODY SEAL TAMPERING
Changing the current coil of meter of the meter i.e replacing it with non std higher sized coils with less number of coil turns
The flux and consequently the driving torque of the disc reduces in proportion to increased coil size and less number of turns, diminishing the meter registration
Shorting the current coils (internally or externally)
Majority of the drawn current is bypassed, through the shunted path and registration goes down considerably
Changing the counter gear of the meter
As the meter disc rotates the correct registration is recorded by a set of gear train, unique for a particular type of meter. When the entire gear assembly of a 3x30/60A meter is replaced with that of a 3x10/20A meter or that of a 3x5/10A meter, registration is lowered by 60% or 80% than actual
Puncturing the pressure coils of the meter
Registration falls by 33.33% when one of pressure coils are punctured, by 66.67% when two such pressure coils are punctured and found totally stopped when all the coils are damaged.
Reversing the incoming and outgoing phase loops of poly phase meter
Registration reduces to 33% when one of the phase loops are reversed, it stops totally when more than one loops are reversed
METHODS OF TAMPERING THAT DO NOT NECESSARILY INVOLVE BODY SEALS TAMPERING
Drilling a tiny hole at the top or side surface of the meter body and counter gears inside meter are rotated with a wire or a prod.
This is done with a purpose to manipulate the display units which may be altered in the described fashion to reduce the actual advance in registration. The consumer thus gets a total control on meter registration
Drilling a tiny hole at the bottom surface of a meter and inserting a stick through this hole that touches the disc
Under this condition the disc gets jammed and fails to rotate, meter registration which is an effect of disc rotation, stops totally.
Drilling a tiny hole at the back of the meter body and puncturing the pressure coils of meter after making access from back
The registration falls by 33%, 67% or stops totally when one, two or all three coils are punctured
Placing a strong magnet on the meter body or in close vicinity of it
The meter registration is reduced or stopped under the influence of this external magnet as it creates a flux that opposes the disc motion. However, prolonged exposure of a magnet may increase the disc rotation
Injecting extraneous signal (D.C Voltage) after disconnecting incoming neutral to meter
The disc rotation is reduced or totally stopped till the time the meter is under the influence of such signal.
Disconnecting the incoming neutral loop of a single phase meter or reversing the incoming phase and neutral loop of a single phase meter
The registration can be changed as desired and the consumer can bypass a major share of his connected load by means of an external earth and simultaneously installing a changeover switch in the wiring circuit.
Breaking the face glass of the meter and manually stopping the disc from rotating
The registration is nil till the time the disc is refrained from being rotated.
Inserting a photographic film through the gap between the face glass and meter body
The film follows a spiral path and jams the disc and prevents it from rotation