relays have multiple ratings.
on the coil side, there is a voltage rating. Often these are rated for one voltage but they can be used with other voltages. after all, a coil is all that is being driven.
as for the contacts, there is a DC rating, an AC rating, resistive load rating, an inductive load rating as well as a hp rating.
best thing would be to post the data sheet and also list the device you want to control. Please indicate if the load is AC or DC.