Symptom-Cause Chart

S Y M P T O M
CAUSE: Does not work Goes off and on at will or flickers Runs dim or bright sometimes Won't go off Shocks
A.  Short/Ground-or-arc-fault/Overload Yes -- -- -- --
B.  Circuit (or main) wire connection poor ("open") Yes Yes partially Yes -- --
C.  Ground-fault without an intact intended ground path -- -- -- -- Yes
D.  Miswiring Yes -- -- Yes Yes
E.  Bad or mis-set device Yes Yes -- Yes --

For a detailed explanation, visit Troubleshooting Step 1.