All my 50Hz phono hum is induced from surroundings via the ground wire.
If I use copper braid shielded wire, will it really help if the braid itself is not grounded? Should I make a lead from the braid to an outlet’s ground pin or what?
maybe try to connect braid shield only on the source side (TT)
Meaning here in the context of the grounding wire’s own shielding braid being grounded, connecting it to what ground on the source side? The signal ground?
Really the susceptibiity of common, plain ground wires supplied with tables and phono cables, to relatively strong inductive coupling from nearby equipment’s transformers and unshielded power cords, is making me question why not more attention in general isn’t paid to a properly isolated conduit for making the required ground, faultless!
I admit to have confusion here.
If I want to shield a ground wire, notably it would seem paradoxical to connect the shielding braid to phono signal ground - that’s what a turntable ground wire essentially transfers, yes?
Am I mistaken in thinking the separate gnd wire for a TT is a supplementary ground that enhances the grounding supplied through phono leads?
(Continuing even if I’m wrong…), So, why would we expect the phono preamp to effectively ground all this to the (pre)amplifier through mere phono leads when we seemingly often need that additional ground wire in the first place?
Why aren’t turntables most effectively grounded straight to the power amplifier?
I had good results with this by using fairly low inductance speaker cable from TT to integrated’s RCA input ground. Though too finicky, as it still required special maneuvering relative to the surrounding fields to have truly low hum.
So I’m left with the option of using a braid-shielded ground wire, just WHERE DO I CONNECT THE SHIELD?
Ha I like this conundrum - what can we connect to to shield ground* 
My (random and possibly wrong) thoughts:
80s (and onwards) TTs seemed to come with two phono leads (i.e. from inside the TT to RCA plugs going into the phone preamp) and a separate ground wire.
It was always my belief that the phono cable was shielded until it arrived in side the TT whereupon somewhere it has to connect to the four twisted wires that go up the tonearm to the cartridge, so no connection of the RCA cable shields to the TT chassis.
In order to shield the twisted wires in the tonearm etc. you had to connect the extra ground wire (which is internally connected to the TT chassis, NOT the phone RCA cables’ shields) to a ground point somewhere - often the same signal ground on the phono preamp, though in theory any ground would do.
I say “in theory” because if the TT chassis was already earthed then that is a potential earth loop if you also connect the chassis (via the extra earth wire) to earth via the preamp.
Therefore I humbly suggest that “shielding” the earth wire is not necessary, but rigorous avoidance of earth loops is necessary.
Add to this the big risk of EM induction from transformers etc. due to the very low level signal from the cartridge, you have reminded me again why I don#t bother with vinyl any more, other than the occasional play - just too many variables!!
* as an aside - the grounding protocols in space craft must be interesting too…
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I’m not even having much of a ground loop, the main source of my phono hum is EM induction.
Now then this made me think… How much would braid-shielding the ground link even help against this? Of course I’m hoping most everything would induce onto the shield and get drained somewhere, but then again since we’re talking magnetic fields… I guess I just need some mu-metal after all.