Why do aed pads need to be placed one inch away from jewelry or pacemakers?

Because if the pad is too close to the metal then it could send electricity and/or shock to the neck or the wrist or wherever the jewelry is and that would cause skin and heart damage.  If the pad were to be placed too close to the pacemaker then the electricity could interfere with the heart rhythm or cause damage to the pacemaker to where i would be able to provide the proper care.