Squier J - earth wiring

[steve-bbb]

ok dumb elec noob question here

ive just unscrewed the cover of my J to see if any loose wires as ive had my amp checked over and it seems ok so i thought maybe an earth problem with the instrument

i only see one wire connection to the jack

is the earth connected via the casing of the three volume and tone pots connecting to the chrome plate? i can see all the black wires going to the pots from the pups and the bridge but no black from any one of them the the jack

thanks

[BOD2]

Yes, the metal plate acts as a common ground/earth connection. The jack socket is screwed onto this plate and that makes a ground contact to the metal plate. Anything screwed onto the plate will also therefore be grounded.

Note that you should also have a ground wire that goes from the control cavity through a hole in the body and up towards the bridge, where it is sandwiched between the back of the bridge plate and the wood of the body to ground the bridge and therefore the strings.

[steve-bbb]

hi thanks yes that is all there too and made sure it was connected well when swapped the bridge over

i was thinking of copper foiling the cavities out to see if the hum lessens a bit - its not too bad with both pickups on but on the rare occasions when i want bridge only there is a fair bit of hum - im guessing also any copper foil lining the cavities also needs to be connected to the ground??

[BOD2]

Copper foiling the cavities might not make that much difference to that particular issue - the hum is likely caused by the pickup itself being a single coil design.

Check that the cavity isn't already painted with a conductive screening paint (it usually has a matt black appearance and there will often be a ground tag screwed into the wood of the cavity and connected to ground).

If there's no grounding then adding copper foil to the cavity won't do any harm but it might stop the noise when working on one pickup only. And yes, the copper foil would have to be connected to ground. Often you can achieve this by overlapping the foil onto the body where the metal plate screws down so that the copper foil makes a good contact with the grounded metal plate.