The spark plug wires on automobiles are responsible for harnessing tens of thousands of volts and delivering that energy to the spark plugs every time the engine is started. Spark plug wires or ignition wires are connected to the spark plugs and distributor or ignition coils. Compared to typical wires, plug wires are built to have a lot of resistance. This resistance greatly reduces the radio static being generated by the ignition system. A standard plug wire has a resistance of about 10,000 to 15,000 ohms per foot of length--if it's measurably higher, the wire will probably malfunction.