- The jumper wire should be the same gauge or larger than the circuit you are jumping out.
- Even if the alligator clips on the jumper are insulated, it is a good idea to turn off the power before you attach your jumper.
- Jumpering across a live circuit usually causes a spark when the alligator clips are connected. Be prepared.
- It is not a good idea to jumper out a high current circuit like a compressor or large horsepower motor.
Jumper wires, when used correctly, are a great tool to help you troubleshoot HVAC equipment. But, when used incorrectly, they can damage the system you are trying to repair. Remember this one important rule - Never place a jumper wire across a load. Here's why: If your place your jumper wire across a switch, all you are doing is closing a circuit that the switch would normally close and allowing current to flow through the circuit. If you place your jumper wire across a load, you are creating a short circuit where one is not intended to be. You will blow a fuse, trip a circuit breaker, burn out a switch, burn wires, or a combination of all or some of the damage listed. Here are a few other things to keep in mind when using jumper wires: