Why did I get an electrical shock by touching the propane tank?

Answer 1

You can get an electrical shock when touching a propane tank due to the buildup of static electricity on the tank. The flow of gas causes a transfer of charge, similar to what happens when you walk across a carpet. When the charged item comes into contact with an item of different charge, such as ground or your hand, current flows to equalize the charge and you see a spark and/or feel a jolt of electricity.

You can also get an electrical shock from a propane tank if you are also touching something, and the tank and that something are not at the same voltage. This is a ground fault, which must be corrected, otherwise there is risk of electrocution.

Answer 2

If the shock is significant and has a "buzzing" sensation to it the hot water heater is not grounded correctly. This is a severe safety hazard and you need to have an electrician check it out and fix the problem.

If instead the shock is just a single sudden "zap" and is over this is normal static electricity discharge from your body to the grounded hot water heater. Don't worry about it.

Answer 3

This is a condition that should not be happening. One of the heating elements in the tank has cracked and a small current is flowing through the water in the tank to the tank's frame. This usually happens when power is applied to the tank without the tank having water in it. If the tank is not properly electrically grounded when you touch it the small current uses you for a return path for the small current leak.
The element needs to be changed out for a new one. If you are going to do it yourself you need to remove the voltage from the circuit by shutting the feed breaker off. The feed breaker will be a two pole breaker because the tank requires 240 volts to operate. Make sure that both sides of the two pole breaker open the supply voltage. Older systems used tie bars to connect two single pole breakers together and some times these tie bars were removed or fell off.

Remove the two inspection doors on the side of the tank. Under the insulation you should see the two terminal points of the heating element where the element enters the tank. Remove the two wires and with a test instrument set on Ohms or continuity test the element. Place one lead on the terminal screw and the other on the frame of the tank.

If the element is good there will be no reading shown. If the element is grounded there will be a reading shown. To determine whether the element is open or not place the test leads across the two element terminals. If there is no reading the element is open and needs to be replaced. If there is a reading and you are on the ohms scale it will read the resistance of the element. There are many sites on the internet that show how this test is done. Use the statement " water tank element resistances".