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Can I Use An Extension Cord For My Hot Tub?

Finding the perfect spot for your hot tub can be deceptively tricky; you need a flat surface, away from walls and windows, access to your hose and so on. If you’ve covered all these bases, but your power cable won’t quite stretch, you’ve probably thought, can I use an extension cord for my hot tub? 

We’ve been testing and researching hot tubs for over ten years, and in that time, brands and manufacturers have remained steadfast about a few things. When it comes to safety, there’s no messing around, which is why the use of extension cords is a pretty hot topic! 

Can I use an Extension Lead for my Hot Tub? 

In the eyes of most manufacturers and experts, using an extension lead with a hot tub is a big no-no. In some cases, this can even void your warranty, as more often than not, the power required to run your hot tub will be too great for an extension power cable to handle. 

If the use of an extension cord is absolutely necessary to power your hot tub, it can be possible to use a heavy-duty 14-gauge (or thicker) cord safely, though you should always:

  • Use the shortest possible length
  • Completely unwind the cable
  • Ensure it’s water and weather-resistant
  • Use a 3-prong grounded plug

Why you Can’t use an Extension Cord for Hot Tubs

two cables about to be connected

Wrong diameter cable

Hot tubs require a fairly high sustained current to power their heaters and jets, so their power cables must be quite thick to operate safely. Generic extension leads aren’t designed to handle such currents and are too small to run safely at only around 1.25mmsq in diameter.

Too long

In much the same way a longer hose pipe results in lower water pressure, a longer electrical cable results in a weaker current. To offset this, you’d need to increase the diameter of your extension cord, though, as covered above, most extensions are already too small.

Unsuitable material 

Your average extension lead is made from untreated PVC, which is perfectly fine for indoor use, but in no way ideal for prolonged outdoor use. This material is susceptible to weathering, UV damage and is unable to withstand temperatures below 5°C, so it won’t last long in your garden! 


A residual current device (RCD) is designed to switch off an electrical current in the event of any dangerous faults. Even though your hot tub has an RCD, it will only cover its own lead and internal electrics, meaning your extension cable itself will not be adequately protected.

The socket isn’t weatherproof.

outdoor plug socket that is wet

Any outdoor plug socket needs to be covered and weather-proof, especially if there’s a full hot tub nearby; if it comes into contact with any water, you’ll run the risk of a deadly electrical shock. A standard extension lead will not be appropriately water or weather-resistant. 

Does an Inflatable Hot Tub Use an Extension Cord?

It is an industry-standard to fit portable spas with a 5m power cable, this way, you have enough length to use an appropriate socket at a safe distance from the water without needing an extension lead. 

Inflatable hot tubs generally use a 13AMP power supply, including a standard 3-pin plug that can be used with your average plug socket. However, manufacturers and experts advise that you only plug these systems into a weather-proof outdoor socket installed by a professional electrician.

Last Word 

We hope you’re all clued up on hot tubs and extension cables now! Hot tubs are a lot of fun, but as with any electrical device, you must be incredibly careful when dealing with live currents.

Electrical safety is even more critical when dealing with spas, as they’re often outside and full of water, so only ever use weather-proof sockets situated at least 2m away from the hot tub itself. 

In some circumstances, or as a temporary measure, a short 14-gauge extension lead with adequate weather-proofing can be used, but as a general rule, it’s best to avoid them altogether! 

John Devlin

Hello, Welcome to my website. I’m John, and I created the InflatableHotTubGuide while researching these spas nearly a decade ago. Since its creation, the site has become the leading UK resource for many models. As a passionate hot tub user, I love to test and explore all the latest machines this industry keeps creating. I hope you find our content helpful.