The connections to the contacts are brought out for use by an circuit that may require them, i.e. they are not tied to any particular voltage (hence 'floating'), in other words, they do not carry any voltage (until they are exploited)

hyperphysics.phy-astr.gsu.edu/hbase/electric/potpoi.html‎
The electric potential (voltage) at any point in space produced by a point ...

DE referenca:(
www.linguee.de/deutsch.../potenzialfreien kontakt.ht...‎
Dieses schließt den potenzialfreien Kontakt 1-2 für 3 Sekunden, wenn der ... This closes the floating contact 1-2 for 3 seconds if the output FPV sends no receive ...