Spark plug voltage is high tension voltage, needed to jump a spark between the plus and minus poles. Needed tension is about a minimum of 10.000 Volt between the poles.
40000
spark plug produces spark in the range of 15000-35000 volts.
The ignition coil increases the voltage to the spark plugs. Without this increase in voltage the spark would not be formed in the gap of the spark plug as it would not have enough voltage to jump from one electrode to the other. All spark plugs have two electrodes, a positive in the center of the plug, surrounded by a ceramic insulator and connected to the coil through a distributor, and the negative attached to the screw threads of the plug and grounded to the engine block to complete the electrical circuit.
The resistance measured under low voltage conditions should be infinite. High voltage ... like that that produces the spark ... behaves differently.
A spark plug is the part of an internal combustion engine which forms a high-voltage spark which ignites the fuel-air mixture to begin the power stroke.
To amplify the voltage going to the spark plug
Vehicle spark plug ignition.
so the high voltage of the battery does not fry the spark plug of anything else
If you know that there is spark at the distributor cap then I would think it would be bad spark plug leads.
I know my Jeep GC has "coil on plug" ignition, so there aren't traditional spark plug wires, just low voltage.
A drain plug for a spark plug? Now why would there be? What would you drain from a spark plug.... the spark? If you're referring to a plug for the spark plug socket, I'm sure you could find something that would fit that would keep out debris while you let you engine sit without plugs. (Why??)