We do not recommend the use of extension cords with our Plug & Play spas as they can cause damage to the GFCI plug on the unit (see below) and pose a risk of electric shock.
A properly located household outlet (ideally a GFCI-protected dedicated outlet) would be the best option to ensure that your warranty remains in tact.*
NOTE: Please also ensure that the plug makes full contact with the outlet.
If water gets into the GFCI plug, it will cause it to trip. Be sure to protect the plug from rain/snow.
If you require any further assistance, please contact Customer Service.
*Any damage determined to be a result of extension cord use will not be covered under warranty. Replacement parts will be chargeable.