By Mike Sokol
Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. This week we’re discussing parking an RV under high-voltage power lines.
Our RV once had hot skin when we were boondocking. We were near a light pole in a parking lot in an event field. We were not plugged into anything, nor did we even own a generator at the time. But when we touched our camper we got a mild shock. Didn’t see any exposed wires on the pole; it looked normal. But we moved to another spot and the trouble went away. —Betty
Interestingly, I wrote about this phenomenon back in 2017. If you park your RV under high-tension power lines, and it’s not plugged into shore power or grounded in any way, you can have an induced voltage on the entire RV of up to 10,000 volts and 5mA of current.
Now, this isn’t supposed to be dangerous, but it can feel like grabbing a spark plug wire on a running lawnmower engine. You experience this same effect just driving a car under power lines, but the current is usually so low in amperage that you can’t feel it. Remember, these power lines can be 110,000, 250,000, 500,000 and even up to 1,000,000 volts. No wonder these power lines can induce a voltage in your RV parked beneath them.
Don’t stand on your RV when under a high-voltage line
There are specific heights these high-voltage lines must be above the ground, typically 28 feet or so for medium voltage ones (maybe 250,000 volts). But if you’re standing on top of your RV under one of these power lines, your body could be less than 10 feet away from it, putting you in real danger. So don’t go climbing up on the roof of your RV while you’re parked under this kind of power lines.
Also, while most states and counties don’t allow houses to be built directly under these high-tension power lines, apparently there’s nothing stopping campgrounds from putting campsites under them. Plus, in at least a few cases the dump station and water faucets were placed under the lines. That gives everyone a mild shock when using the hose to wash out your waste pipe. I’ve talked to a few power company engineers about this problem, and they’ve all assured me it’s perfectly safe.
Hot-skin on RV when under power lines and not grounded
However, once you’ve plugged your RV into shore power it’s now grounded by the campground electrical system, so this hot-skin voltage should disappear and you should not feel a shock from your RV. And once you move away from these power lines, this hot-skin voltage will also stop, so it won’t leave your RV charged with electricity in any way. It will only happen when your RV is parked under those high-tension power lines while it’s not grounded.
Read more about it HERE.
OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
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