Troubleshooting: Use a test tool, such as a voltmeter or ammeter, to step through each part of the circuit to find the point of failure. Cables, connectors, switches, etc. Analyze the incoming line part: Determine the incoming line source of the distribution box and. Knowing your distribution box helps you see which breaker does what. This makes fixing problems faster and keeps you safe. Verify the lights and indicators work. All LV switchboards should be completely cleaned, vacuumed, and given a thorough. Check the electrical load and ensure that the sensors do not exceed the 10 Amp maximum. Check each wire for damage that may lead to a short.