A commercial panel upgrade usually starts with a specific change: a new tenant with heavier equipment, added HVAC or refrigeration, an EV charging fleet for a parking structure, or a build-out that pushes past what the existing service was ever sized for. The panel itself rarely fails first. It’s the load that outgrows it.
Start with the equipment or tenant change driving the review
Most commercial panel conversations begin with a specific project, not a general concern about age. A restaurant tenant bringing in new kitchen equipment, an office switching to a heavier server room or added HVAC, a retail space adding refrigeration, or a property owner planning EV charging stations for tenants or customers all change the electrical demand on a building’s service. Each of those changes the answer to “does this panel have room,” and each needs its own load review rather than a guess based on the building’s age or square footage.
Property managers overseeing multiple sites across San Diego County see this most often at lease turnover. A new tenant’s equipment list rarely matches the outgoing tenant’s, and an electrician needs to see the actual proposed loads, not the prior tenant’s setup, before recommending anything. If the driver is a build-out rather than a panel itself, our tenant improvement guide covers that scope in more depth, since a TI project and a panel upgrade often overlap but aren’t the same job.
Older commercial buildings across the county carry the same age-related risk that shows up in older homes: equipment that was adequate for a building’s original use but wasn’t built for today’s mix of computers, refrigeration, and electronics. A strip mall built decades ago for a mix of small retail tenants can end up hosting a restaurant, a medical office, or a fitness studio, each with electrical demands the original design never anticipated. The panel isn’t necessarily failing on its own. It’s being asked to do a job it was never sized for.
How an electrician evaluates existing commercial capacity
An assessment starts with identifying the building’s existing service size and configuration, then reviewing the panel schedule against what’s actually connected and what’s proposed. Commercial services are frequently three-phase rather than the single-phase service typical of a house, which changes both the equipment involved and how a load calculation is done. The electrician should document existing loads, planned additions, and any spare capacity, rather than simply eyeballing open breaker slots.
Ask for that load calculation in writing, with its inputs shown, not just a bottom-line recommendation. A proposal that separates confirmed equipment from possible future additions is easier to evaluate than one that bundles everything into a single number.
Multi-tenant buildings add a layer most residential jobs don’t have: shared infrastructure. A single service upgrade can affect several tenants’ metering and billing, not just the space where the triggering project is happening. Before scoping any work, the electrician should map out which panels and meters serve which tenant spaces, since a change intended for one suite can unintentionally touch power to a neighboring one if the building’s original wiring wasn’t documented cleanly. That mapping step alone can take real time on an older building, and it belongs in the proposal’s scope, not treated as a surprise discovered mid-project.
Panel replacement and service upgrades aren’t the same
A panel replacement swaps failing or outdated equipment for new gear at the same amperage. A service upgrade increases the amount of power the building can draw from the utility, which is a bigger project involving the service entrance, the meter, and often utility coordination, not just the panel enclosure. A tenant with new equipment might need one, the other, or both, and a proposal should say clearly which one it’s scoping. If a bid doesn’t distinguish between the two, ask the electrician to explain exactly what’s being replaced and why.
Sub-panels for a specific suite or piece of equipment are a third, often cheaper, path when the main service already has room. Whether that’s viable depends entirely on the load calculation above.
The right answer also depends on timeline pressure. A tenant with a lease start date and a build-out deadline may not have room for a full service upgrade if that project turns out to require utility-side work with its own lead time. Knowing early which category a project falls into, rather than discovering it late in the design process, is often the difference between hitting a tenant’s opening date and missing it.
How shutdown planning affects the project scope
Commercial panel work usually requires killing power to some or all of a building or suite, and the scheduling question matters more here than on a residential job because of tenant operations, refrigeration, security systems, and equipment that can’t tolerate an unplanned outage. We’re not going to state a shutdown duration here, because it depends entirely on the scope of your specific project, the building’s configuration, and utility coordination requirements. Ask your electrician for a shutdown estimate specific to your building and confirm it in writing before scheduling, especially if you’re coordinating around a restaurant’s service hours or a tenant’s operating schedule.
Which permits and utility steps require confirmation
Commercial electrical work requires a permit through the jurisdiction where the property sits, whether that’s the City of San Diego’s Development Services Department, another incorporated city, or San Diego County’s Planning & Development Services for a property in an unincorporated area. We’re not stating a specific commercial permit fee or review timeline here, since those vary by jurisdiction and by the size and complexity of the project. Ask the electrician handling your permit which office it goes through and what documentation that office requires.
Service upgrades that add capacity typically need coordination with SDG&E as well. SDG&E’s planners evaluate load requirements, meter location, and existing system capacity as part of that process, and the utility, not the electrician alone, ultimately confirms what’s required on their end.
Depending on the building’s use, other reviews can layer on top of the electrical permit, including fire and life safety review for occupancies like restaurants or assembly spaces, and energy code compliance for lighting and controls on a build-out. None of these reviews move at a guessed pace, and a property manager juggling a tenant’s move-in date should ask the electrician and any other trades involved which agencies are in the approval path for this specific project, rather than assuming the electrical permit is the only step standing between design and opening day.
Ask early whether your project needs its own dedicated meter or whether it will run through building-wide service shared with other tenants. That single question can change whether SDG&E treats the project as a straightforward capacity request or a more involved service planning case, and getting the answer late in design is one of the more common reasons a commercial electrical project slips its original schedule.
What property managers should compare in proposals
When comparing bids, look for a documented load calculation with its inputs shown, a clear statement of whether the scope is a panel replacement, a service upgrade, or a sub-panel, and a permit plan that names the correct jurisdiction. Ask each bidder for their C-10 license number and verify it directly at the CSLB license lookup rather than taking a business card at face value. A proposal that skips any of these, or that quotes a single number with no explanation behind it, is harder to compare honestly against one that shows its work. Our commercial electrician guide lists other questions worth asking before you sign anything, and our commercial electrical and panel upgrade service pages describe the scope of each in more detail.
When to call us
A commercial panel or service upgrade needs a licensed electrician who can document the load, name the correct permitting path, and coordinate with SDG&E where a service change is involved. Call us at (858) 988-5580 and we’ll connect you with a licensed local electrician.