Technical Foundation
What Is a Extension Cord?
An extension cord's wire gauge (AWG) and length together determine its safe current-carrying capacity — the smaller the AWG number, the thicker the wire and the higher its rated amperage, but as cord length increases, voltage drop increases proportionally, so a cord adequate at 25 ft may be undersized for the same load at 100 ft. Using an undersized gauge for the load and distance causes the cord to overheat, which is both a fire hazard and a cause of tool/motor damage from voltage sag.
Outdoor-rated cords use a jacket material (commonly SJTW or SJEOW) rated for moisture, UV and abrasion resistance, and should never be substituted with an indoor-only cord for outdoor or wet-location use. GFCI (ground fault circuit interrupter) built into a cord adds shock protection required by code for many outdoor and wet-location temporary power applications, independent of the cord's gauge/amperage rating.
Prefer a quick quote?
Get Extension Cords Pricing in Your Inbox
Skip the search — tell us the amp draw of your equipment, cord length and indoor/outdoor use and we will come back with pricing.
| Spec | What It Means | Why It Matters |
|---|---|---|
| Wire Gauge (AWG) | 16, 14, 12, 10 AWG common | Lower AWG number = thicker wire = higher amp capacity; must match the connected load's draw |
| Length vs. Amp Capacity | Effective capacity decreases with length | Longer cords need a heavier gauge to carry the same load without excessive voltage drop |
| Jacket Rating | SJTW (indoor/outdoor), SJEOW (extra oil/weather) | Determines moisture, UV and abrasion resistance for the use environment |
| Amperage Rating | 13A, 15A, 20A typical | Must exceed the connected equipment's actual amp draw with margin, not just match it |
| GFCI Protection | Built-in GFCI vs. standard plug | Required by code for many outdoor and wet-location temporary power circuits |
Shop Extension Cords
Browse Extension Cords Sub-Categories
Organised by wire gauge. Pick a sub-category, or provide the equipment's amp draw, required length and indoor/outdoor use and let ChatMRO match a properly rated cord.
How it works
From Half-Remembered Part Number to PO, in Three Steps.
Ask
Type an MPN, paste a spec sheet, or describe the part in plain English. ChatMRO understands engineer-speak.
Compare
Side-by-side specs, cross-references, and equivalents from multiple sources — without the clutter of endless browser tabs.
Quote & Buy
Request a quote or add to cart. Volume discounts, VAT-aware pricing, and consolidated procurement — all in one place.
Applications
Where Extension Cords Get Used
Extension cords are specified wherever equipment needs temporary or supplemental power beyond a fixed outlet's reach, indoors or outdoors.
Construction & Jobsite Power
Heavy-gauge, GFCI-protected extension cords for running power tools across a job site.
Industrial & Manufacturing Facilities
Heavy-duty cords for temporary equipment power runs on the plant floor.
Outdoor Landscaping & Grounds Maintenance
Weatherproof cords rated for wet-location use with outdoor power equipment.
Warehouses & Distribution Centers
Cord reels and extension cords for temporary power to equipment and charging stations.
Events & Temporary Power Setup
Heavy-duty cords distributing power to lighting, sound and vendor equipment at outdoor events.
FAQ
Extension Cords Questions, Answered
What gauge extension cord do I need for my tool or equipment?
Check the equipment's amp draw (on its nameplate) and match against a cord gauge/length chart — as a general guide, 16 AWG suits light loads under 25 ft, 14 AWG handles moderate loads to 50 ft, and 12 or 10 AWG is needed for higher-draw equipment or longer cord runs. When in doubt, a heavier gauge than strictly required is always safer than undersizing.
Why does cord length affect what gauge I need?
Voltage drop increases with wire length, so the same gauge cord that adequately powers a tool at 25 ft may cause excessive voltage drop at 100 ft, leading to overheating in the cord and reduced performance or damage to the connected motor. Longer runs need a heavier (lower AWG number) gauge to deliver the same load safely.
Can I use an indoor extension cord outdoors?
No — outdoor use requires a cord jacket rated for moisture, UV and abrasion resistance (commonly marked SJTW or similar outdoor-rated designation); an indoor-only cord's jacket isn't designed for wet-location exposure and using one outdoors is both a code violation and a shock/fire hazard.
Do I need a GFCI extension cord?
GFCI protection is required by code for many temporary outdoor and wet-location power circuits, and is strongly recommended for any outdoor power tool use even where not strictly mandated, since it interrupts power far faster than a standard breaker in the event of a ground fault, reducing shock risk.
How do I know the amperage rating I need?
Sum the amp draw of all equipment that will be plugged into the cord at once (or the single largest draw if used one tool at a time), then select a cord rated comfortably above that total — running a cord at or near its rated maximum continuously accelerates wear and heat buildup.
Keep browsing
Related Categories
Explore More
Find Your Next Part Now.
Describe a part number, spec or what it does.