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.
Dear Mike (aka J.A.M.),
This just happened to the 30-amp plug on my surge protector. (picture). Any idea what would’ve caused it? I blame the outlet in the pedestal, but the park owner (of course) blamed the surge protector. What can cause a brand-new shore power plug to burn up? —RVillager Shanik117
See the picture below, which you can click on to enlarge.
Dear Shanik117,
Why, yes I do have a few ideas about what can cause a power plug to overheat and burn up, none of which blame the surge protector for the problem.
This is most likely caused by loose or corroded contacts in the pedestal outlet itself, or possibly loose screws in the outlet. Remember last week I said you should turn OFF the circuit breakers before plugging or unplugging your shore power cord from the pedestal? Well, this is what happens when the pedestal outlet is worn out from too many previous campers who plugged and unplugged their power cord without turning off the breaker. The brass contacts inside of the outlet become pitted or corroded, which reduces the surface area and increases the resistance, which causes heating. The heating causes the spring-loaded contacts to soften and loosen up. Then the loose contacts create even more resistance, which causes even more heating to occur. And voila! Fricassee of shore power plug.
NOTE: If you notice that your shore power plug is loose when plugging into a campground pedestal, DO NOT accept the pedestal since it may destroy your shore power cord or surge protector. And just like the example above, the campground may not want to pay for your damages. So ask to be moved to another campsite/pedestal or proceed at your own risk.
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 40+ 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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A good project for Rv Travel/Electric: Provide, or make available to campgrounds and Rver’s xthr resistant labels to apply to the inside of the box: “WARNING: Turn off breakers before and after use”. Red on white background with a lightening strike symbol! Enforceable Code change? I have always done this when dealing with a power box – just because I am very afraid of things I can’t see – like electric currents!
I like the concept, but your phrasing wouldn’t work for 90% of folks, the remaining 10% being the folks that already understand and don’t need the stickers. Maybe more direct DANGER: SHUT OFF BREAKER BEFORE CONNECTING OR DISCONNECTING. Yes, technically there’s little danger at that moment, but as this article highlights, there is danger from habitual ignorance.
Also, although sheets of stickers are CHEAP, there would be some expense across all the campsites nationwide, so someone would have to fund the printing and distribution, all so that people would disregard them anyway. Maybe someone makes a design and people order and apply them in their travels “with permission”.