It may not be the wires. That may of been a corona. If it was a spark, your wires are bad, but if it was like a blue halo around the length of the wire, that was just a corona which forms when there is high voltage in a cable. The air around the cable gets ionizes and you a get a neon like, blue glow that flashes with the firing of that plug.

My name is Richard. I was a Contouraholic. NOW: '02 Mazda B3000 Dual Sport, Black BEFORE: '99 Contour SE Sport Duratec ATX Spruce Green PIAA 510's, Foglight MOD, K&N Drop-in