Not 'advertising' here, just informing . I have discovered 'Industrial Quality' Christmas lights of ALL kinds at 'Novelty Lights' http://www.noveltylights.com/led_christmas_lights . They are 'Commercial quality' lights and wiring , and even have C-7 and C-9 'screw in base' bulb replacements for those smart enough to have KEPT their old incandescent light strings ! They ARE available on Amazon.ca and other sites in limited styles , but if you want to go to the 'Mother load', go to their U.S. .com site !
Yes, a little more expensive perhaps, but FAR less 'frustrating' so far . I'M going to ordering 100 C-7's for sure , my C-9's have lasted for 8 years so far with '0' problems (except for the 2 I broke off their bases by standing on them , and those I just unscrewed and replaced , no struggle !
Any further strings I buy will be from them ! NO 'Box' stores .
Cheers,
Drew