My electrician made a 4' mistake in running a new line to our pool. Instead of going to all the trouble of running a new line I would like to just replace the plug wire coming from the pump. I don't know squat about this.
What does SJTOW mean?

Water and oil resistant, flame retardant. If wiring, replace with longer duplicate connections. To be safe, have electrician check out. GFI?
Electricity can kill.