3 Tips To Consider When Choosing An Extension Cord

3 Tips To Consider When Choosing An Extension Cord

With so many extension cord options, it can be hard to make the right choice. Do you go with the “one size fits all” approach or purchase a cord specific to each application? The following three tips will help you choose the right extension cord for any scenario.

1. Environment & Usage

First, consider the environment you are working in. The outer layer of the cord (jacket) protects the wires from moisture, direct sunlight, cold etc. The jacket has a designation that is made up of a sequence of letters, and each letter has a meaning.

Designation reference guide:

Designation Letter Meaning
S Flexible cord is rated for general use.
W Cord is rated for outdoor use.
V Vacuum wire, softer and more flexible than standard "SJT", usually found on retractable cord reels.
J The cord includes a 300V insulation. Please note that if the "J" is not included the extension cord includes a 600V insulation.
P Indicates a parallel wire construction, used in air conditioner cords.
T Cord jacket/cover is made from vinyl thermoplastic.
E Cord jacket/cover is made from thermoplastic elastomer rubber.
O Cord is oil resistant.
FT2 This letter group means the product is flame retardant.
CL2 Sometimes referred to as class 2, it is a UL rating for wire that can be used for in-wall construction.
SRDT Heavy-duty wire made specifically for use with higher amperage equipment.
HPN High-heat parallel neoprene wire, used where high temperatures of the appliance could affect the power cord's performance.

2. Plug Type

The majority of extension cords have either two or three-prong plugs. Depending on your application you may require a specialty plug for higher amperage devices and/or specific safety features.

Plug type


Here are some common features you will come across:

  • Built in GFCI
  • Connector box
  • Multiple sockets
  • Twist & lock
  • Light indicator

3. Power Rating

It’s critical that you choose an extension cord that can handle the power requirements of the devices you are connecting. Below are a few things to consider.

  • Be aware of the amperage of your tools; this will ensure you have an extension cord that is rated to be used under such amperage.
  • Remember “amps = watts/voltage”
  • It is not uncommon to find that your cord does not include a maximum amperage rating. We have included below a cord gauge vs amperage diagram to help you choose the right extension cord.
Cord Gauge vs Amperage