[RFI] Mains filter for test bench

[Missouri Guy]

Hi Gents,

I need a simple mains filter for my test bench to attenuate
noise on the AC line that powers some sensitive instruments.  

Power is via a dedicated, 15-amp 117vac line, directly from
the AC mains entrance panel.   I plan to place the filter
at the test bench and make it a in-line, plug-in style...one input and
one output.  No other connections.  

>From what I've read, there's some question of whether or not to
run the grounding wire, along with the "hot" and neutral
wires, through a say, a 2.4"i.d. #77 mix toroid.   There are no other
grounding conductors at the test bench.

So, should I run the grounding conductor through the 
toroid (as a trifilar winding) or not?  I'll use multiple turns
of #14awg wire though the toroid.

Thanks in advance for your input.

Charlie, N0TT