How to Tell if an Extension Cord is for Outdoor Use

If you’re using outdoor electric tools, you’ll want to make sure you have the right extension cord. 

This means making sure it’s rated for outdoor use and also making sure it’s the right amperage rating for the tools you’re using. 

What Do Extension Cord Ratings Mean?

First off, outdoor rated cords will say “SJTW” on the package. This is a standard rating system from Underwriters Laboratory (UL). 

  • SJ = hard service grade
  • T = thermoplastic (basically the PVC coating)
  • W = outdoor. 

You’ll see this on every outdoor cord. If it says it’s outdoor but doesn’t have this SJTW rating, don’t buy it. If you already have the cord and want to check, this info will be stamped near the male (prong end) of the cord. 

Generally, outdoor cords have 3 prongs (so they’re grounded), have a tough rubbery coating, and come in bright colors like orange or yellow.

What Size Extension Cord Do I Need?

All cords come with a number listed on the packaging or cord like “16/3” which means it’s 16 gauge and 3 wire grounded. It will also list the maximum amps, volts, and watts that can be safely handled by the cord.

The most common outdoor extension cords are 16 gauge and rated for 10 amps or 1250 watts. 

This is fine for some smaller tools like electric drills but for more powerful outdoor equipment like mowers, circular saws, and chainsaws you’ll want a 12 gauge cord that’s rated for 15 amps. Most residential breakers trip at 15 amps so pretty much every outdoor tool fits in that rating.

If you’re not sure what the amps are for a tool, you can look on the metal plate on the tool itself. In the picture below, my reciprocating saw has a 10 amp rating. If you want to be really sure, it’ll also be listed in the owner’s manual. These are almost always posted online these days.

Amp rating on power tool

One final note. The power you get out of a cord decreases with its length. So get the length you really need. No need to get a 100 foot cord if all the work you’re doing is 30 feet from the outlet. Also, a shorter cord means less to trip over not to mention less annoying knots.

What is the Best Outdoor Extension Cord?

There are lots of cords to choose from and, frankly, most will work – for a while at least –  as long as you get the right gauge. That said, it’s worth getting a good quality cord. Cheap ones have thinner coatings that crack over time (definitely not good when there’s rain or snow around). They also tend to have cheaper prongs that bend or break which is just plain annoying. 

So, while many will work, I do have a favorite, the Southwire 100 foot contractor grade cord. 

  • Made in America
  • 12 gauge plenty for home needs and comes in various lengths
  • Rugged outer jacket lasts and lasts
  • Solid, reinforced prongs
  • Lighted female ends to let you know it’s plugged in
  • Southwire brand name

First off, I love to recommend made-in-America products and this is one of the few that really is (the subtle clue is the red, white, and blue colors and the “made in America” stenciling along the cord). There’s also a very similar yellow version if you prefer that color.

It comes in various lengths and is UL listed and 12 gauge which is plenty for pretty much any home power tool need. It’s got a noticeably thicker, rugged feeling outer jacket that really lasts and gives you confidence it won’t easily get nicked or kink up.

The prongs are also reinforced and really solid. There’s nothing more annoying than prongs that bend at an angle making plugging it in a real pain. 

Finally, it’s got a lighted female end that lights up when it’s plugged in so you know it’s live. 

If you don’t know the Southwire brand, it’s one of the biggest suppliers of wire and cable manufacturers in the world based right here in the USA. Odds are pretty good your house has some wire from them in it and you get your electricity over their power lines made by them. In short, they know wire so you can feel confident you’re getting a quality extension cord from them.

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