That's a Good Question!
Greg Stevens was asked, “Is it safe to take a shower or bath during a thunderstorm?” and here is what the CDC states:
No. Lightning can travel through plumbing. It is best to avoid all water during a thunderstorm. Do not shower, bathe, wash dishes, or wash your hands. The risk of lightning traveling through plumbing might be less with plastic pipes than with metal pipes. However, it is best to avoid any contact with plumbing and running water during a lightning storm to reduce your risk.
So, I practiced the best form of engineering and called a friend. Ken Sellars recalled the day when he was 8 years old and his mom was doing the dishes during a storm – metal faucet, metal piping, metal sink, and a smart kid standing far away. He recalls seeing the brightest blue flash of light he had seen up to that point in his life. I was so shocked by this statement that I forgot to ask him if his mom was okay!
But did e-Hazard’s Joe Rachford drop a dryer in the bath? (watch that here). So, if the hairdryer didn’t leave us like my 03’ MDX’s battery every 18 months, why would lightning be different?
Now, for current to flow, there needs to be a conductive return path to complete the circuit (preferably, not through your body). In my experience with home wiring, the person is usually holding onto the receptacle box or standing on a conductive surface like concrete. In the dryer video, Joe makes it clear that his scenario contains a non-conductive bath and non-conductive piping. This was not the scenario that Ken described!
Step and Touch Potential
Understanding lightning is important. Lightning rarely kills through a direct strike, but rather creates two dangerous phenomena that we explain during our electrical safety training classes: step and touch potential.
Step potential is caused when lightning strikes produce a voltage gradient on the ground that you are standing on. If your feet are apart and end up in different voltage regions, then your situation will be similar to the happy bug that found the pretty blue light (or cattle in the field?).
So – are you standing on a conductive surface? Is your shower insulated from the concrete? Now you know why electrical safety folks love homes with wooden flooring – it’s 10 megaohms to 10 gigaohms resistance on a bad day (and why termites love it too)!
Touch potential is caused when a lightning strike creates an electromagnetic pulse that couples with magnetic metals (similar to the broadcast towers producing radio waves to couple with a radio antenna) and induces voltages on that metallic / magnetic system. You can experience shock through a faucet, electrolytes (water), metal pipes, drain pipes, etc.
So, if you are unsure as to the build of your house, unsure whether that faucet is metallic and magnetic, unsure of the tiles being insulated from the concrete, unsure of whether you should be holding that dryer, unsure whether to watch momma do the dishes or help her do the dishes, the folks at e-Hazard say that when there’s “thunder over Louisville,” delay that cleaning or cleansing regimen.
Since we are approaching the Kentucky Derby season, let me end by saying that we would love to hear from you; even “neigh-sayers” are welcome.
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