Jumper on isolator

There's a jumper wire on my isolator - I think this is the jumper described at http://www.gmccoop.com/information.htm:
"""
Yes, we have no alternator!


What would you do if your alternator went out and you had another 200 miles to go? Simple, turn on your generator and place an 8ga. jumper wire across the 2 outside terminals on your battery isolator up front. Your 110-12volt converter will be powered by your generator and will produce 12volts. The jumper will supply this power to the chassis battery to prevent it from dropping and will allow you to run on and charge the chassis battery without the alternator. Go by Radio Shack and get a heavy gauge jumper and you're set!


Another similar tip: You can place the same jumper on the isolator as above and charge your chassis battery from the living area power converter when plugged to shore power! On restorations, I install a "knife switch" there to give a simply solid connection any time it is needed. Call us if you need more explanation.
"""