ND5XS - chassis or floating

Hi!

Happy new year to all!!!

I came across this here in the manual of my ND5XS:

The NDX/5XS is fitted on its rear panel with a Signal Ground
switch offering two positions: Chassis and Floating. Select
the Chassis position unless NDX/5XS is connected in a hi-fi
system incorporating another earthed source component,
or mains “hum” is audible through the loudspeakers.
Contact your retailer, distributor or Naim for advice if
necessary.

Note: “Connected” in the context above means an
analogue audio signal cable that includes an earth
connection.

Now, I have a turntable via the Superline (earthed to the Superline) going as an analogue signal into my Supernait. 

So according to the description I should put the switch on my ND5XS to "FLOATING", right? 

Since already a source component ( = TT) into the Supernait is "earthed"...

Thank you in advance.