The most common problems relating to noisy guitars are improperly wired pickups and poor grounding. With Seymour Duncan humbucker pickups it is important to not only connect the red and white wires but also to insulate them with electrical tape or shrink tubing. If this connection is not insulated it can come into contact with ground and cause the humbucker to run off of one coil, robbing the pick up of it's noise canceling capability.
Ground connections from the input jack; bridge ground or the ground wires from the pickups should be inspected and re-soldered if they look dull and gray. Bad ground connections account for much of the noise problems in electric guitars. Also, an inexperienced solderer can over heat the potentiometers chassis and ruin them. Over heated potentiometers can also cause excessive noise in a guitar.
Keeping the stripped portion of all wires inside the guitar as short as possible will also help to keep the incidents of shorts down to a minimum as well.
WRITTEN ON JUNE 15, 2015, BY