Hi and welcome!
Typically the eac is powered only when the blower is powered. Usually on the newer air handlers with a circuit board, there is a screw terminal designated for the eac. To wire your new eac, usually wires are run from this to a surface mounted metal box on the side of your unit containing a single recpticle to plug the eac into.
If it is an older style, then you would need to install a "sail switch" in the duct work before the recepticle.
Either way, do not cut the plug off!
If this is beyond your range of experience, please hire a licenced hvac or electrical contractor to do the install.
Hope this helps!