If You've Just Bought Commercial Property, You Need To Update The Wiring
A piece of commercial property can be a lucrative investment, but you have to be sure the property is in great shape if you want to have long-term commercial tenants. Updating the wiring, and really the entire electrical system, is necessary if it's an older property. Anyone who leases space from you should be able to plug in what they need to, from several computers to copiers to vacuums, without having to count up watts and amps. You'll also want to be sure the building's wiring is legal, now that you're the owner and thus the responsible party.
Update the Wiring While Remodeling the Building
Chances are you're going to be remodeling the building if it's old; if you are, take care of the wiring at the same time. Don't wait and see how things go or assume that everything looks fine from your perspective. Codes for electrical wiring change constantly, and what you have has to be safe to use. The best time to change out wiring and fixtures is before you start leasing space and while you're tearing everything else out anyway.
Ensure All Rooms Are Now Up to Code
Something you should have a commercial electrician do, even if you're not planning any major renovations, is to make sure each room is up to code in terms of electricity. Test all the outlets and switches to make sure all work completely (and that means making sure all three of the openings in an outlet are properly wired), make sure all outlets near sinks and other water sources are GFCIs, and ensure the light fixtures can take LED bulbs. If the building has many fluorescent fixtures, speak with the electrician about replacing them. If nothing else, you'll be able to use bulbs that don't require special hazardous-waste disposal methods.
Consider Adding Power and Changing the Wire Gauge
Power flows to circuits through wires of a certain gauge, or diameter. The typical 15-amp circuit uses #14-gauge wire, and 20-amp circuits use #12 (and sometimes #10). If the building you bought has a lot of 15-amp circuits and a lot of #14 wire, you may want to have an electrician upgrade the wire to #12 at least. You can have a 15-amp outlet on a 20-amp circuit with #12 wire. You can't install a 20-amp outlet on a 15-amp circuit that uses #14 wire. Even if you have no plans to change circuits from 15 to 20 amps, using the #12 wire allows you to change out the circuits later on if you desire (or rather, have an electrician change them out).
Discuss all this with a commercial electrician. There may be quirks in how your building is built that require special attention, or there could be additional upgrades that would be beneficial.