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.
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Dear Readers,
I’ve received a number of emails and Facebook comments this week about 30-amp RV extension cord plugs overheating and melting. Now, these particular failures aren’t where the shore power cordset is plugged into the pedestal or the RV itself. These meltdowns seem to occur where a 25-ft. extension cord is plugged into the RV’s shore power cordset. And, yes, many times it’s the connector that’s laying on the ground.
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But it worked just fine for the last year…
Well, oxidation (corrosion) on most all metals occurs from a combination of oxygen and moisture, so having your 30- or 50-amp shore power cord hooked to an extension cord laying on the ground is asking for trouble. Now, it might work just fine for the first year or so. And if you’re in a dry desert environment it might work forever. But the first time it rains the brass contacts in your plug and extension cord will begin to oxidize (corrode). After that begins it’s a fast ride to overheating and meltdown failure, especially if you’re running a portable space heater or air conditioner in your RV.
What’s a mother to do?
I used to bag and gaff-tape all my sound and lighting power connectors that we knew would be in the rain, but for RV owners there’s a simpler and more elegant solution. I found this cool cord cover a few days ago and have asked for a review sample.
But in the meantime, I think it’s a great idea you might want to try yourself. Note that it will accept a 30- or 50-amp extension cord, even with the power-grip handles.
Lift me up – Don’t let your connections sit in water and corrode
However, I don’t like the idea of this cord cover laying on the ground where just a few inches of water could flood it out. I think that placing it on an overturned 5-gallon bucket is a much better solution.
Of course, if the water gets over 2 feet deep you’re in really deep do-do, so I think a regular bucket is more than fine. As soon as my sample unit comes in I’ll a take a picture of it on a bucket in my flooded back yard. In the meantime, you can get one for yourself 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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I’ve always had that connection elevated by at least a brick and put plastic bag over it to keep out rain. Just kinda made sense to keep it dry and off the ground.
Consider using a marine shore power cable for an extension.
Has male and female twist lock connectors at the ends, so one connects it between the RV cable and the RV.
With a sealing collar, the connection between the RV cable and the marine cable is waterproof.
Note, more expensive than the straight connector extension cable commonly sold at big box stores.
One way we have gotten around this issue is to use dielectric grease. While not 100%, it does help protect both the male and female contacts. Also, if we are in a damp environment or rain, I use a plastic milk box and put the connected cables on top. Also have a vinyl sleeve with velcro closures the wife made. I can run one end of a cable in, connect it to the other cable, slide it back in and close the velcro ends. Still can get some moisture inside, but the connection stays dry. Total cost was less than $10. The milk box takes up no space as I store the power cable and extension cable in it….multiuse.
Mark Polk used a Tupperware-like container:
https://www.youtube.com/watch?v=noBtXZiX3ew
Pretty cheap and ok to use unless there’s heavy rain, etc.
I may be deluding myself, but I coat my plug ends with dialectic grease on a regular basis. Doesn’t take much. My question is whether this is actually helpful……
Yes, that should help. But keeping the connectors will help even more. 👍
Thanks Mike. After this article and reading these comments I understand and will definitely do this.
I had a problem recently where I positioned the cord from the trailer so that the rain could run down the cord and into the connector. Result: tripped GFCI. I repositioned it so that there was a “drip loop” so that any rain coming down the cord would drip to the ground rather than into the connector. If you use a box like you showed, make sure that the cords coming in to the box are lower than the box at some point to keep water from running into the box.
Since I now have a simple way to measure ground leakage currents from rainwater on power plugs, that would be a fun experiment to run.
Re your question on GFCI tripping, I never had a problem with my Winnebago Travato camper van tripping GFCIs till I had a Aims 2K watt inverter/ATS installed. Had an electrician come over. He found that disconnecting the neutral shore power input to the inverter stops it from tripping outlets. Verified as well that it’s not a hot skin situation. Just something about the inverter. Called Aims tech support and the response: “Yep, they’ll do that”. Have since found a similar review on Amazon – too late. Great. Electrician installed a 2 pole switch that allows me to break that connection in the rare event we’re using a GFCI shore power connection. During that time, the inverter can still power the plugs and microwave (the only things supported by the inverter) via the lithium batteries.
It’s likely due to the noise filter capacitors that are connected between line and neutral.
Thanks Mike. That’s what he suspected too. Guess this is the best way to deal with the situation short of experimenting with more inverters. That gets expensive real fast! At least everything works.
I also have occasional issues at the pedestal. I use a surge protector and some power pedestals are that low to the ground that the plug is laying on the ground. The surge protectors pigtails are very short and do not allow for much movement. I made up a 4 foot extension cord and a hanger to plug every thing in and then cover it with a garbage bag in the event of rain. I use the same method as Cal to cover my connectors, works great.
I bought this: https://www.amazon.com/dp/B006EUHT2W/ref=cm_sw_r_em_apa_i_oRY8FbB6DXBTW?_encoding=UTF8&psc=1
Always borrowed my wife’s Saran Wrap and a roll of electrical tape to seal the edges plus a large pan from the kitchen to keep it off the ground.
Been looking for this solution. We try not to use an extension cord. Have only been to one commercial park where we needed an extension. Our favorite park. We just know which site to avoid.
I carry 7 quart plastic food container with a snap on plastic lid. It’s 7” high and I have cut outs on opposite sides for the cord to pass through. I lifts the cord about 5” off the ground and If it’s a rainy area I bag the whole container with a 13 gallon kitchen trash bag.
That 7 quart container was about $6 at Walmart. I’ve had it for over 10 years and it’s still going strong. I might add that it sits on my driveway in Kansas in triple digit temps and sub zero freezing too.
I do something similar with two 5-gallon buckets. I’ve notched one of them out to accept the connectors, and set the second bucket over top of it to keep out the rain. Lot’s of ways to accomplish this, just don’t let your electrical connections lay out in the rain or in a puddle of water.
I carry a piece of wood for those occasions where I need to use my extension. That and a plastic bag would keep the plug off the ground for a little water.