I have a 10 strands in a matrix I want to supply power to. I can't power it through the controller as it is fully commited power wise. It is 10 strands of 42 ws2811 nodes. So this is 10x42x0.6W/pixel = 252W total. I have a 350W PSU so that is 72% load. So that should be okay. 252W/12V = 21A total. Now for the wiring up. I have 2.5mm2 cable. This is good for 22A but that is a bit close to the wind. So say I run two cables to the matix. It is a 2.5m long run. So 10.5A per cable. Resistance is .0066/m = 5*.0066 = 0.033ohms. Voltage drop = 11*.033=.36V. I can live with that. Now my issue is when I get to the matrix I have to join to pigtails that are rated to say 7 amps or less. Can I just solder on two pigtails at the end of the wire and half the amps. So 5.25 amps each. If this is correct then how do I fuse the cable. Do I put a 15 amp fuse back at the PSU. I am worried that the 7 amp pigtail will melt before the 15 amp fuse blows if there happens to be an issue. Do people put smaller 7.5 amp fuses between the large cable and each of the pigtails. Can this be done or do I need to run enough cables so that I can have a fuse that is rated 7.5amps so that it will blow before the pigtails melt. Any tips on how people normally supply power to these things will be greatly appreciated. I don't need this up by kick off on the weekend but I am planning on getting it going this year before Christmas if possible.