Not all extension cords are equal. I list in my new own tips not to use an extension cord, unless 12 ga, some 14 ga cords work fine too. However some cords listed as 14 ga have not worked, I have one of them, it will not work it is 50' long. Several have confirmed problems with extension cords, yet others say their MES works fine using a cord. So best answer buy a 12 ga, they are NOT cheap, but you know it will work. Best of all you can use that cord to run heavy equipment like a duty table saw.