I would of thought it is, the starters create massive surges, and if its got a bad connection it just wont spin the starter over, yet everything else will work, try and lose them extra connections if u can, looks messy aswell. If the wrong nuts are used on the battery aswell that wont help matters, the type with the built in spinning washers are the best, a lot larger surface area, and it helps keep the terminal flat, most problems are well people just bung on a normal 10mm nut