An extension cord is typically not recommended, but... a good quality heavy duty 20A cord (as short as possible) should be okay if that is your very last option.


The wire size matters but the weak link in many extension cords are the plug and socket assemblies so take that into consideration as you select one. 


Additionally, The power requirements of the lasers differ by wattage and the 130W units require a dedicated 20A plug, meaning that a 130W Thunder laser will not plug into a standard 15A 110VAC outlet. This needs to be taken into account when choosing a cord so the connectors will be compatible. 





PLEASE SEE THE FULL THUNDER LASER POWER REQUIREMENTS ARTICLE: Thunder Laser Main Power Requirements



40W to 100W Nova series machines have a standard 15A 110VAC plug but that doesn't necessarily mean it only requires 15A to operate the system. A 20A 110VAC dedicated circuit is strongly advised for all installations. 


The 40w and 60w machines can run on a  dedicated 15A 110VAC circuit. 


The 80w to 130w machines must have a solid 20A 110VAC supply.


Here is an example of a good cord:

 https://www.amazon.com/Yellow-Jacket-2991-Generator-T-Blade/dp/B000HEC2DW/



These are often used with generators, etc... so if you search in that realm you can weed out a lot of the standard duty cords. And be sure to specify 20A. 


The bottom line is you need to know 3 things:


  1. How long the cord has to be
  2. What type of plug is on you laser's main power cord
  3. What type of outlet are you plugging the cord into


You cannot swap a 15A plug out with a 20A outlet. The breaker is still 15A and the wire is not rated for 20A circuits. If you have questions about this beyond the scope of the laser's power requirements you may want to seek the advice of an electrician.