Thursday, March 30, 2023


Make plug-in electric heaters safer with SmartPlug

Product review

By Bob Difley

Portable heaters are a convenient way to ward off the season’s chill, but these devices increase amperage loads that poorly maintained electrical systems can’t handle.

SmartPlug Systems, maker of the revolutionary SmartPlug, offers tips to identify potential safety hazards in a shore power system, and ways to safeguard against overheating and possible fire.

With a traditional twist-type connector, pitting and corrosion forms on the metal surfaces due to arcing. A moist environment speeds the process. With less surface contact, electrical resistance increases causing overheating, especially when running high-amperage devices like heaters. Scorching – a yellow or brown discoloring – around inlet pins is the first sign this is happening and that the parts should be replaced.

SmartPlug Systems’ Retrofit Kits include everything needed to safeguard against this and other dangerous shore power situations. Its easy-to-use design provides more than 20 times the metal-to-metal surface contact to safely and efficiently transfer maximum electrical power.

Unlike twist-type power cords, the SmartPlug System has dual locking clips and a sleeved inlet that is easier to use than older traditional styles. The asymmetrical design pushes straight in – making connecting easy, even in the dark.

Replacing an inlet and connector is straightforward and requires only common household tools. Instructional videos on the process are available here.

The Retrofit Kits include an inlet and connector and are easily installed using an existing cable. The inlet typically uses the existing mounting hole pattern. It comes in four trim colors: black, white, grey and stainless steel.

For more information visit the SmartPlug website or Amazon.

You can find Bob Difley’s RVing e-books on Amazon Kindle.



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Gary Stone
4 years ago

I’ve seen too many instances of burned, scorched and melted old-style twist plugs. The boating industry has been using the SmartPlug for years. The SmartPlug is a small investment for personal safety. VERY easy to DIY install to your existing 30-amp or 50-amp cable.

Mike Sokol
4 years ago
Reply to  Gary Stone

I’ve received a number of emails about burned twist-lock shore power plugs on RVs, and it appears that many users aren’t aware that you need to “twist” the plug to lock it, and you must spin on the locking ring for full support. Unless you do both things every time, then you risk reducing the contact area which can result in plug overheating.

John Whitney
4 years ago

I purchased a 50 amp complete kit for RV end. Went to install it, and the back of the fixed socket had the screws for the wire end exposed. No missing cover. The installation instructions showed exactly that. Since the back of my receptical was exposed, the smart but unsafe plug went back. Beware!

Richard Edmonston
4 years ago

Sounds more like a shore connection rather than for a heater. As such title seems misleading.

4 years ago

Richard. I agree. What does this have to do with my plug in heaters?

Very misleading title.

Gary R
4 years ago

The heavy current draw of an electric space heater can cause the shore power inlet to overheat if there is a poor connection, thus increasing fire risk. The more robust connection of the SmartPlug is intended to remove that risk.

Mike Sokol
4 years ago
Reply to  Gary R


That’s 100% correct. For example, two 1,500 watt space heaters in an RV will draw around 12.5 amperes each, for 25 amps combined current. If you have a 30-amp shore power connection, according to the National Electrical Code it must be derated to 80% of listed capacity for continuous-duty loads such as space heaters. So your 30-amp shore power wiring is only listed for 24 amps of heater loads that could be drawing 100% of their rated current for hours on end. So even two 1,500-watt space heaters are theoretically overcapacity for a 30-amp connection without anything else running at the same time. And if you have any sort of poor connection from corrosion or other damage, the chance of overheating is even more possible.

Now it’s correct that the pedestal circuit breaker should trip eventually if you run a lot of continuous loads, but remember it’s likely to be located out in the freezing cold, which will allow it to pass higher currents for longer than if it was in a 100 degree ambient temperature. They ain’t called “thermal trip” circuit breakers for nothing.

What this all suggests is that you want the most robust shore connections for your RV possible, and don’t use any skinny extension cords or power strips in the circuit path of portable space heaters. This starts at the pedestal and your shore power cordset. I have a dissected SmartPlug in my demo kit, and it’s designed to withstand that type of continuous, high-current loads. I highly recommend them.

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