How to Wire an Amp Meter

by G.K. Bayne

The use of an amp meter allows you to see the amount of current an electrical circuit is consuming. Amp meters work on a direct current (DC) electrical circuit. DC circuits are primarily found in electronic and automotive electrical devices. The amp meter is placed in series with the electrical system. In other words, all of the power must pass through the amp meter.

Check the rating of the DC amp meter you are wanting to place in the circuit. It must not be lower in the amperage rating than the circuit you are placing the meter into for measurement. In other words, do not place a 10 amp rated meter into a 30 amp DC circuit, as you will damage the amp meter from a too high of a current through the mechanism.

Disconnect the positive side of the battery terminal to remove all power from the automotive electrical circuit. Failure to do so may cause an accidental short to the frame of the vehicle causing damage to the battery.

Locate the power wire in which you want to place the amp meter. Cut the wire with the wire cutters.

Place the wire next to the female portion of the ring connector, where the wire fits into the connector. Use the wire strippers and strip back the insulation the same length as the ring connectors wire length.

Place the ring connector over the bare copper wire, and crimp the female cylinder onto the wire with the wire crimpers. Perform this operation on both wires.

Place a few rounds of the electrical tape over the female connector portion of the ring connector. This will help to insulate the bare connector from "shorting" to any part of the metal frame on the vehicle.

Connect the wires to the amp meter in the following order. The positive side of the meter must be connected to the positive power wire or the wire coming from the power source. The negative side of the amp meter will be connected to the wire that is going to the electrical device. Tighten the nuts on the meter posts with the wire pliers.

Install the meter into the dashboard or your own chosen location by following the manufacturers instructions for proper mounting. Some amp meter manufacturers offer a special mounting kit with the amp meter assembly.

Replace the positive battery post connector to the battery, and engage the electrical circuit by either starting the vehicle or switching "on" the device circuit.


  • check If you must extend the power feed wire for any reason, it may be a good idea to solder the new extension wire for a complete circuit instead of using an electrical crimp butt connector. Always place a fuse inline, before the amp meter, with the same size of the rating of the amp meter. This will protect the mechanical operation of the meter and the electrical devices it serves.

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