Why Electrical Design Can't Wait
Most tenant improvement projects move fast. You sign a lease, measure the space, pick paint colors—and suddenly the landlord wants a start date. That urgency makes it tempting to figure out electrical later. Bad move.
Every outlet, network drop, light fixture, and dedicated circuit must be roughed in before drywall closes the walls. Once framing is covered, adding a circuit means cutting holes, patching, repainting. A $150 rough-in turns into a $1,200 change order. Multiply that across ten outlets you forgot and the budget bleeds.
Start electrical planning the day the lease is inked. Walk the space with a licensed commercial electrician before your general contractor frames a single wall. Map workstation clusters, conference rooms, break areas, server closets. Identify which walls will carry low-voltage data and which need 20-amp circuits for copiers or coffee makers.
Early planning also catches code gaps. Commercial spaces require AFCI protection on certain circuits, dedicated 20A lines for kitchen appliances, emergency exit lighting on separate branch circuits, and tamper-resistant receptacles in some jurisdictions. Miss any of that during rough-in and the inspector red-tags your certificate of occupancy.
Power Requirements: More Than Desk Lamps
Every office has predictable loads—computers, monitors, printers—but tenant improvement electrical goes beyond plugging in a laptop. Think about high-draw equipment first.
A multifunction copier or laser printer can pull 12-15 amps under peak load. Put that on a shared 15A circuit with six workstations and you're tripping breakers weekly. Copiers, large printers, and floor-standing coffee machines each need dedicated 20-amp circuits on 12 AWG copper branch wiring.
Conference rooms often host projectors, screens, laptops, and phone chargers simultaneously. Plan at least two duplex receptacles per wall, split across separate circuits so one breaker trip doesn't kill the entire room mid-presentation. If you're installing a large display or interactive board, verify the draw and spec a dedicated line if it exceeds 10 amps.
Break rooms and kitchenettes are power hogs. Microwaves pull 10-12 amps, refrigerators another 6, coffee makers 8-10. The NEC requires two 20A small-appliance circuits in any space with a sink and countertop. If your build-out includes an under-counter fridge and microwave, you'll need at least three circuits just for that alcove.
Data Drops and Low-Voltage Backbone
You don't hire an electrician to pull Cat6, but coordinating low-voltage rough-in with power rough-in prevents crossed wires—literally. Data cables running parallel to branch circuits for more than a few feet pick up electromagnetic interference, especially near fluorescent ballasts or motors.
Best practice: plan cable pathways so data and power cross at right angles when they must share a stud bay. Better yet, run low-voltage lines in separate bays or use metal conduit to shield them. If your IT vendor pulls data after the electrician finishes power, make sure they know where circuits run so they don't accidentally drill into a live 120V line.
Modern offices often want network drops at every desk, plus ceiling drops for wireless access points. Mark those locations during your walk-through. A typical open-plan office installs one WAP per 2,500 square feet. Each access point needs a PoE data drop and sometimes a separate outlet if it has a local power supply.
Don't forget AV and security. Conference-room ceiling speakers, wall-mounted cameras, door access panels—each has a home run back to a central rack. Coordinate those pathways with your electrician so conduit routes don't conflict and junction boxes land where you need them.
Lighting Design: Function Before Fashion
Lighting changes the feel of a space, but it starts with code minimums. The IBC and local amendments dictate foot-candle levels for offices, corridors, and restrooms. Your general contractor's architect should specify a lighting plan, but the electrician implements it—and often catches errors.
Open offices typically use recessed LED troffers on 8×8 or 10×10 grids, each fixture controlled in zones so you're not lighting empty corners at full brightness all day. Dimmable drivers cost more up front but slash energy over a ten-year lease and let employees tune light levels for task work versus video calls.
Private offices and conference rooms benefit from separate switching: overhead cans on one switch, wall sconces or pendants on another. That flexibility matters during presentations or when natural light through windows makes overhead fixtures unnecessary.
Emergency egress lighting is non-negotiable. Battery-backup LED exit signs and illuminated path-of-egress fixtures must run on a dedicated circuit, fed from a separate breaker or from an emergency panel if the building has generator backup. Your electrician will coordinate placement with the fire marshal's requirements during plan review.
Consider occupancy sensors in restrooms, storage closets, and private offices that sit empty for hours. The sensors pay for themselves in six months and some utility rebates cover half the install cost. If your lease includes a tenant improvement allowance, those sensors often qualify as energy-efficiency upgrades the landlord will fund.
Panel Capacity and Service Upgrades
Many older commercial buildings have 100A or 150A panels serving each tenant space. That was fine in 1995 when offices had desktop PCs and fax machines. Today's build-outs add server racks, 65-inch displays, EV charging in the parking garage, and kitchen appliances—loads that didn't exist two decades ago.
Before signing off on electrical plans, ask your electrician to perform a load calculation. NEC Article 220 lays out the math: square footage, general lighting, receptacle circuits, dedicated appliance loads, motor loads, and demand factors. If the existing panel can't support your planned load with 20% spare capacity for future growth, you need a service upgrade or a new subpanel.
Sometimes the building's main service has room and the landlord will install a larger tenant panel at no cost, especially if it increases the space's value. Other times you'll negotiate who pays. Either way, you want that conversation during lease negotiation, not three weeks into construction when the electrician opens the panel and discovers aluminum feeders that max out at 125A.
Subpanels are common in large tenant spaces. If your build-out spans 5,000+ square feet, expect a main panel near the building's service entrance and a subpanel closer to heavy loads—kitchen, server room, or a wing of private offices. The electrician will size feeder conductors to handle the subpanel's rating with minimal voltage drop over the run.
Permits, Inspections, and Certificate of Occupancy
Every commercial build-out electrical job requires permits. The contractor pulls them, not you, but understand the timeline: permit submission, plan review, corrections, approval, rough-in inspection, final inspection. In South Florida, plan review can take two to four weeks depending on AHJ workload.
Rough-in inspection happens after electrical boxes, conduit, and wiring are in place but before insulation and drywall. The inspector checks wire gauge, box fill calculations, AFCI/GFCI protection, grounding, panel labeling, and that circuits match approved plans. Any deficiency gets red-tagged. Correction and re-inspection add a week.
Final inspection happens after drywall, fixtures, devices, and trim are installed. The inspector verifies every outlet is live, polarity is correct, GFCI buttons trip and reset, exit signs illuminate, and panel schedules match reality. Only then does the building department issue a certificate of occupancy—your legal permission to move in.
Don't let your general contractor schedule furniture delivery before the electrical final passes. Seen too many tenants stuck with a load of desks in the parking lot because an inspector found a mis-wired three-way switch or a missing cover plate. Hire a detail-focused electrician from the start and you'll pass the first time. For help with commercial electrical planning and tenant improvement work, visit our services page or reach out directly.
Common Build-Out Mistakes (and How to Avoid Them)
Even experienced project managers trip over the same electrical pitfalls. Here's what goes wrong most often.
Underestimating outlet count. Tenants routinely spec one duplex receptacle per workstation and discover employees need two—one for the PC and monitor, one for phone charger, desk lamp, and external drive. Plan 1.5 duplex receptacles per person minimum, split across two circuits so a breaker trip doesn't kill the whole row.
Forgetting future growth. You lease 3,000 square feet but only build out 2,000 today, leaving the rest as storage. Fine—but run conduit and a subpanel to that future space now, while walls are open. Pulling wire through finished ceilings costs triple.
Ignoring dedicated circuits. Every 240V appliance (electric water heater, HVAC split system, EV charger) needs its own circuit. Many 120V devices do too: sump pumps, server racks, medical equipment, large aquariums. If it draws more than 10 amps continuously or has a compressor/motor, give it a dedicated line.
Mixing switched and unswitched receptacles. Offices often switch half the outlets in a room so plugged-in lamps turn on with the wall switch, while computers stay hot. That's a smart design—if the electrician knows which outlets to switch. Mark your plans clearly or you'll have desks going dark every time someone hits the switch on the way out.
For more guidance on commercial electrical work and code compliance, check our blog for industry updates and how-to articles.