Reel: Extension Cord Calc — Support

Need help?

Email roman.kopaliani@gmail.com with your question. Please include:

• What you were trying to do
• What happened instead
• The app version (Reel → More → About)

Frequently asked

What's free and what's in Reel Pro?

Free forever: the Cord Gauge Guide (including verdicts for your own cord across the whole catalog) and Cord Safe. Reel Pro ($6.99, one-time) unlocks Cord Match, Voltage Drop, and the Generator Hookup. No subscription.

What gauge extension cord do I need?

It depends on amps AND length. Per ESFI: at 25–50 ft a 16-gauge cord carries up to 13 A and 14-gauge up to 15 A; at 100 ft those fall to 10 A and 13 A; at 150 ft even a 12-gauge cord is done at 10 A. Find the amps on your appliance's plate (or divide its watts by 120), and remember: lower AWG number = thicker wire. Reel does this lookup for you, plus the voltage-drop math.

The package says "heavy duty" — isn't that enough?

No standard defines "heavy duty" on cord packaging — it's marketing. The spec is gauge × length × amps. The gauge is printed on the cord jacket itself, in the jacket code (e.g. "SJTW 16/3" is a 16-gauge, 3-conductor outdoor cord). Read the jacket, not the package.

Why does Reel say my space heater can never go on a cord?

Because the fire agencies say so. Per USFA and NFPA, space heaters plug directly into a wall outlet — never an extension cord or power strip. Portable heaters account for about 3% of home heating fires but 41% of the fatal ones. That verdict is permanent in Reel: no gauge or length input softens it, and it will never be behind the paywall. The same applies to EV charging, per every EV maker's mobile-connector manual.

My tool runs, so the cord must be fine — right?

Not necessarily. An undersized cord drops voltage, and a voltage-starved motor doesn't run slower — it draws more current and runs hotter. Chronic drop is how saw, compressor, and mower motors die mid-season. Reel flags drops past the NEC note's ~3% line as marginal and past 5% as undersized.

Can I run my house on the generator through an extension cord?

Only small loads. Past 20 A — or any 240 V transfer-switch load — no household extension cord qualifies; that's twist-lock generator-cord territory. And whichever cord you use: the generator runs outside, well away from windows, and the cord comes to it — generator exhaust is a carbon-monoxide kill zone.