If your low voltage lighting system malfunctions, you may get left in the dark. Commonly used for landscape lighting, these systems may experience malfunctions due to inadequate or improper power flow. Voltage and amperage testing are ways to ensure your outdoor lighting system receives the proper electrical supply. The failure may occur at the transformer or at the individual fixtures, so knowing how to test both can help identify the location of your low voltage lighting system's malfunction.
Test the Transformer
Locate the transformer for your low voltage lighting system.
Touch the tip of a voltmeter's test lead to one of the transformer output leads. Touch the tip of the voltmeter's other test lead to the remaining transformer output lead.
Read the number displayed on the voltmeter's gauge. This represents the voltage delivered to your outdoor lights.
Open the clamp of an ammeter and close it around one of the transformer leads.
Read the number on the ammeter's display. This number represents the number of amps drawn through that lead. Check the manufacturer's instruction manual to verify the correct voltage and amperage your particular transformer should deliver. If the voltage or amperage are lower than required to run your lighting system, this means the malfunction lies at the transformer.
Test the Lighting
Remove the light bulb from the socket of the fixture you wish to test. Make sure the transformer is on and functioning.
Insert the test leads of a voltage tester into the empty socket of the light.
Read the number on the voltmeter's display. This number represents the voltage delivered to the light.
Screw the light bulb back in its socket.
Open the clamp of an ammeter and close it around the lead delivering power to the fixture.
Read the number on the ammeter. This number represents the amount of amps the light is drawing. If the voltage or amperage are lower than required for your system, this means the malfunction exists between the transformer and this light. Repeat the testing process with all lights beginning at the one closest to the transformer and working your way out along the line.