While the world of cordless tools is expanding, there is still a need for corded tools for construction and home improvement. Which leads to a common question: what kind of extension cord do I need? The best rule of thumb is: the heavier the rope, the better.
You'll find extension cords typically ranging from about 18 AWG (smaller gauge wires) to 10 AWG (larger gauge wires), and may vary in length from 6 feet to over 100 feet. Like choosing the right ladder for the job, knowing which extension cord will ensure you have the correct type. This comes in handy when you are inserting the Milwaukee SawZall Reciprocating Saw from the other side of the job site.
The length determines which extension cord you need
Lest you think it's all math (actually, it is) one thing to keep in mind when determining which extension cord you need is that power is lost through the extension cord. This means that the longer it is, the less current you can safely deliver to the tool, and the thicker the wire gauge (AWG) needs to be to carry the required current. Remember that thicker AWG (wire gauge) is indicated by a smaller number).
Extension cord length and ammeter
Here's a "cheat sheet" on recommended electrical extension cord lengths per amp (current) rating:
|
current (ampere) |
25 feet |
50 feet |
75 feet |
100 feet |
150 feet |
200 feet |
|
0 – 5 amps |
16 |
16 |
16 |
14 |
12 |
12 |
|
5.1 – 8 amps |
16 |
16 |
14 |
12 |
10 |
— |
|
8.1 – 12 amps |
14 |
14 |
12 |
10 |
— |
— |
|
12.1 – 15 amps |
12 |
12 |
10 |
10 |
— |
— |
|
15.1 – 20 amps |
10 |
10 |
10 |
— |
— |
— |
Also, check out our extension cord size chart for more information on how wire gauge and amp interact.
cost associated with size
Of course, cost is a function of length and wire size, so the larger the wire size and the longer the wire, the higher the cost will likely be. The reason heavy-duty cord is a better choice is that it gives you more flexibility to connect to the cord without damaging your power tool or burning out the extension cord (and anything that might come into contact with it).
What happens when the wire is undersized is that due to the resistance not enough current flows through it, this causes the wire to heat up, sometimes to dangerous levels, the shielding on the wire can melt and can cause a short circuit or even a fire. This is Something to avoid at all costs, and the main reason why nearly all power tools include an amperage rating and a recommended maximum extension cord length for a power tool similar to the one pictured above.
Another thing that can happen when you're using an undersized extension cord is that the power tool you're using may require a certain amount of volts and amps for the motor to run properly. Now, if the cord is undersized, the tool will have to work harder, which in some cases can damage the power tool. Knowing what extension cord you need to provide the proper power to your tools will help you work safer and more efficiently.
Like the extension cord in our featured image? They are custom made under the Pro Tool Reviews name and are manufactured by Southwire. Find out more here or visit your local Southwire supplier to order yours!