Lightning cannot directly strike you if you’re inside your house. But the electricity produced by a lightning strike can travel through wires and other conductive surfaces. If you happen to be in contact with one of them, it’s possible you could can get electrocuted.
In addition to outdoor fatalities caused by lightning, a number of people are injured indoors every year, including individuals who are using their landline telephone during a thunderstorm (Source: Medscape).
Lightning is a master of trickery and can do some pretty strange things. But, the odds of you being struck by lightning while inside a building are considerably worse than winning the Powerball lottery.
Houses have a lot of internal wiring. There is solid gauge copper wire leading to every wall outlet, light switch, and electrical appliance. Copper telephone lines leading to every phone jack. Coaxial cables running from your antenna or cable TV provider snake through the walls. Most of these conductive wires start at some distribution point outside your house such as a utility pole or a satellite dish on your roof. If lightning happens to strike nearby, it’s possible the electricity could find it’s way inside your house.
It’s also possible for the lightning to directly strike your house, then arc flash onto the conductive copper wires. If the house’s grounding system is broken or inadequate, this can exacerbate the problem. If you happen to be on a landline phone, you could get a jolt right to the head!
Conductive copper pipes providing city water also run into each house, but they are buried underground. Moreover, most newer houses use Plex tubing made of plastic which is not conductive. So the risk of electrocution while taking a bath or shower is lower these days.
Interestingly, the iron gas line coming into your house are also conductive, but like the copper pipes, they are buried underground. In 2019, a lightning strike did hit a tree severing a gas line outside a home which resulted in a small fire (Source: CTV News Canada), The good news is, no houses were damaged and I have yet to read any article of a house blowing up due to a gas line being struck by lightning.
When I lived in North Carolina, the homeowners right behind us had their house struck by lightning. It went right through the top of their asphalt shingled roof creating a 2×2 foot hole. The electrical current arc flashed to the wiring in the attic, ruining just about every electrical appliance plugged into an outlet.
The wiring inside the walls vaporized, blowing out chunks of drywall and left black acrid scorch marks in their place. About 35 feet from the front of their house was a utility pole. Moreover, their house was surrounded by 60 foot pine trees. That day, the path of least resistance didn’t include any of those taller objects, but was instead their asphalt shingle roof.
Here is a link to some pictures of another house unlucky enough to be struck by lightning.
Just remember, the safest place to be during a thunderstorm is in your house. The odds of being struck by lightning while inside are far worse than winning the Powerball lottery. If you happen to live in a part of the country that experiences a lot of lightning strikes, a good investment might be some sort of lightning protection device such as a properly grounded lightning rod or surge arrestor. But even those will not provide 100% protection.
The cheaper solution is to stay off the landline phone, unplug important devices from the wall outlet, and cross your fingers you won’t have to file an insurance claim!