I had to run a couple of extension cords outside in the weather and I didn’t want the plugs to be exposed to the elements. This is a quick guide for making a simple weatherproof extension cord junction box to keep the rain and snow out of your extension cords.
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Daisy-Chain of Extension Cords
I really do not like running more than one electrical extension cord together outside in the elements for any length of time. The joint where they plug into each other can get wet and potentially blow a fuse (or worse).
Of course, you can purchase a ready-made weatherproof connection box or water-resistant plug-cover but in a pinch, it can be nice to make your own. Follow these instructions to make your own electrical cord junction box and save yourself a few bucks!
Better (More Official) Method that Requires Basic Wiring
If you don’t mind some simple wiring, then I recommend this IP68 waterproof extension box. They are cheap, ready-made and perfect for things like underground sprinkler wiring, CAT5 extensions, outdoor grills, etc…
Tesla Charger Extension Cord
Sometimes you need extra distance from the charging outlet to the vehicle. A good example is if you go camping with your Tesla and need to charge it from the site electrical box. In cases like that, I would recommend this highly rated 30-ft 50-amp extension cord.
Not sure which charging station to put in your garage? Consider hard wiring this Wifi enabled charging station. Once installed you can get the full 48-amp charging for e.g., a Tesla Model 3, for fast charging at 11 kW continuous. Then monitor the progress from the app…
Make a Simple Weatherproof Junction Box
Take a disposable food storage container and drill a hole in each side. Then cut a slit down to the hole. Tie the 2 extension cords together and plug them into each other as shown.
Feed both cords into the slits and holes that you created. Then put the cover on.
It makes a nice protective cover for your cords.
Obviously, this junction box is not completely waterproof, so don’t let it sit in a puddle. Think of it as water resistant… But it does keep the weather out for the most part!
Check out my other Life Pro Tips for home maintenance!
If this simple box isn’t going to cut it, I’d recommend this weatherproof connection box as an alternative.
Thanks for reading and have a good one!
Richard
Practical Mechanic 
This is a great idea. My problem is I have a cover over my outside electrical outlets. The Christmas lights guy allowed enough slack on the light cord that when unplugged I can still close the cover. But I am tired of running out to the side of the house to plug and unplug the lights. I want to add an outdoor timer but the timer is way too bug to sit inside the cover. Any ideas on how to protect the box and the light plug that connects to the timer?
Hi! Just found this article and thought I’d add a bit — you can also use plastic bags in a pinch. Create holes just large enough for your cords, then seal the bag.
We’ve also created these and used caulk/waterproof sealer to retard the intake of moisture into the container. You can use a lightweight desiccant (eg. salt, rice, silica gel) after sealing.
Thanks for the article!
Great tip, thanks for the comment!