Depends on the locale, but in all honesty, for insurance purposes, if you touch the wall switch/wiring as a business, that generally means some sort of electrical license is going to be needed.
In a few of the states I carry licenses in, the low voltage (controls side) has specific voltage cutoffs, others cut off fire alarm and security into 2 licenses, while others allow me to do HV connections and wiring from a HV electrician installed breaker, only for the purpose of powering our equipment, not for switching loads, etc. (think power supplies and FACP's).
If you're going to be changing switches and outlets and the boxes contain HV, then that would be an electrician's job....how you deal with it varies (subcontract, getting licensed yourself, etc).