Installing exhaust cam on 4-8-4 Northern

[JRP]

I have a new HO 4-8-4 Northern that came with DCC.  I have just installed a sound decoder to go along with it, but also want to get the "chuff" sound in sync with the cylinders.  I purchased a Sound Trax cam kit and it calls for the cam to be "slipped onto the axle with the insulated side of the cam facing the drive wheel".

My question is this:  Because all 8 large drive wheels on this loco each have a thin copper connector for power, how will this affect the cam that needs to be electronically connected to the axle?  Will the copper connector cause the cam to not operate?

Does my question make any sense? 

Thanks.  JRP  "Great Southwest and Pacific RR"