30 amp plug smoking; warn RVers! | A Blog from RVtravel.com


Dear Chris, BURNED 50A TWIST

A couple weekends ago, we were using close to the rated 30amp draw on our trailer with fridge, water heater, periodic microwave, HVAC etc. when my son suddenly told me that the power plug outside was smoking slightly. When I looked, sure enough our plug was melting in the socket! I actually had three ammeters running at the moment (genny output, AC input, and an experimental graphing smart monitor) and they all agreed we were at about 27 amps for the last few minutes before meltdown. Yes, close to maximum but not quite over. Just to check for a defective main breaker, after replacing the plug, I intentionally put 32A draw on for a few seconds, and the breaker popped immediately. How normal is it for slightly less than 30A to still dangerously overheat the shore cord? I would have expected a margin of safety that apparently doesn’t exist here. Is there anything else I should check? If this IS normal for borderline draws, perhaps the newsletter should warn folks to stay further below the max draw? -Wolfe

Dear Wolfe,

This is a great point, and it’s not just because of the amp draw. This is likely the result of resistive heating. Resistive heating occurs in an electrical connection where power can’t flow freely, usually because of a poor or dirty connection.

Let’s look at a hose. Water is measured in pressure (psi) and flow (gpm or gallons per minute.) Firefighters use different size hoses for different water flows. Would you see a firefighter go into a fire with a garden hose? No, because it can’t flow enough water. On the same note, a firefighter is in a fire and he loses pressure on his line, only to find that it has gotten caught under a door which has restricted the flow.

The same thing happens with electrical conductors. If the contact in a plug doesn’t connect firmly due to age, heating, corrosion and/or being bent, then as it tries to pass the electrical energy it starts to have arcing at the contact, which heats the metal, it expands, and the problem worsens. Over time, with repeated heating, this will get worse.

Campground plugs/receptacles are continuously connected and disconnected, and abused in other ways. So, if the terminals on either side were bent and/or corroded, this would lead to exactly what you experienced. The plug and receptacle assembly normally can pass this amperage without an issue. Unfortunately the contacts do wear on both sides which can lead to this condition.

We did a video some time ago on the SmartPlug which is designed specifically for coaches with removable shore power cordsets. They designed their system to correct this very issue, just on the RV side instead of the campground side. Click here to watch the video.

You will have to replace the plug on your shore power cord. Unfortunately because of maintenance and wear issues on the campground side, you probably can’t prevent this from happening. Many RVers never experience it, but those that do, including myself, just have to make the repairs.

Note: The SmartPlug 50-amp inlet charger connector combo kit is available here at Amazon.com. The SmartPlug 30-amp inlet charger connector combo kit is available here at Amazon.com.


About smokeycamping

Well let's see have lived in NY for my whole life, have always loved the outdoors (as long as it is warm out) have always hated the cold, and like a dummy have stayed in NY. But now with my second try my wife, we have been camping now for well over 25 yrs. We currently own a 2010 Cedar creek silverback 35TS and can not wait to get out on the highways and see this great country we all call home. Hope to see every National park before my medical issue becomes too bad to travel. I love my African gray parrot (she is my baby) and have two dogs at the time brother and sister mutts, but love them all the same. Have always been a big Nascar fan, love computers (have a number of certificates to build and work on them) am trying to learn photography, enjoy light hiking, being with good friends and folks. country music, pop music and just being outdoors. So I hope someday to meet some of the great people who like what I like and post out there in some great campground somewhere in the country, till then I will keep posting and I hope you keep liking.

Posted on October 22, 2014, in The world as i see it as a camper and who loves his country and tagged , , , , , , , , , , , , , , , , , , . Bookmark the permalink. Leave a comment.

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