Transcript In this video, I’m going to answer the question, what is the difference between SPT-1 and SPT-2? The simple answer is that SPT-2 wire has insulation that is 50% bigger than SPT-1, that’s it. The wire inside the insulation carries the same maximum current of 10 amps. So, this is a piece of SPT-1… Read more… What is the difference between SPT-1 and SPT-2 when it comes to Christmas lights?