Hum coming from Turntable


I need help in tracking a slight hum on my turntable.   I did narrow it down, and the cause of this would be my turntable.   Is this due:

1) cartridge not grounded properly 
2) cartridge wires are loose
3) turntable grounding is bad 
4) phono cable not properly shielded

Can any members/technical person that work on turntable can help me out.  Much appreciated!
128x128zipost
1) Does the cartridge even need to be grounded? The two wires come off if each coil
2) doubtful to be causing a hum
3) Seems the most likely to me

4) I would doubt #4 unless the RCAs were running along side of a power line going into the TT.
holmz… my household grounding is excellent, all of the ground are properly attached.  
Motor and speed controller are both unplug, i still get a hum noise.  
Fyi… i am using a Forsell Air Reference and Air Tangent tonearm.   The table materials are acrylic and wood, and the tonearm is made of plastic and aluminum with Rca output for the Tonearm.  
The Google Wifi was causing a hum for me.  Had to move it farther away from the turntable.

Broken ground inside tonearm was also a cause at one time.



@zipost it has nothing to do with you household grounding.It is likely a magnetic field if it is 60 Hz.
But it could also be a ground loop.