A fleet depot buildout fails in one of two predictable ways. Either the operator sizes the service and transformer for the fleet they hope to have in five years, sinks the capital before a single van is ordered, and pays interest on capacity that sits idle for years. Or they build for exactly the vans on the lot today, then discover eighteen months later that adding the next ten vehicles means a second trench, a second utility application, and a second round of the same lead times they just finished waiting out. Both mistakes come from the same error: treating the electrical build as one decision instead of two.
The fix is to split it. Some parts of a depot's electrical infrastructure are cheap to size for the end state now and expensive to enlarge later: conduit runs, panel and switchboard space, the transformer pad. Other parts should track actual vehicle arrivals, not a five-year forecast: the chargers themselves, and often the transformer's actual kVA rating. Get that split right and a depot can add vans in phases without a re-trench every time the fleet grows.
Why depots are a different electrical problem than a fixed site
A retail lot or an office park adds chargers to serve drivers who show up on their own schedule. A fleet depot is different in a way that changes the electrical math: the operator controls both the vehicle count and when those vehicles charge, and that count is usually going to grow. A pilot of 5 to 10 vans this year is rarely the plan; it is usually a step toward electrifying 25 percent to 40 percent of the fleet within a few years, then the rest over a longer horizon. An electrical infrastructure assessment done for a fixed retail site can reasonably assume the load it studies is close to the load that gets built. A depot assessment has to study a moving target on purpose, because the whole point of the buildout is that it keeps moving.
That has a direct electrical consequence: depot charging is pushing commercial sites toward the highest power levels the industry uses. Overnight Level 2 charging still covers most light-duty depot fleets running predictable local routes, but medium- and heavy-duty vehicles on tighter schedules are increasingly served by DC fast charging in the 150 kW to 400 kW range so a truck or van can recover most of its range during a shift break rather than overnight (industry coverage from charging-equipment manufacturer Ekoenergetyka and charging-software vendor JointCharging both name depot and fleet charging as the fastest-growing segment of commercial charging in 2026, driven by that shift toward medium- and heavy-duty electrification; treat the growth framing as vendor-reported context, not an independent market study). A single 150 kW port asks more of a service and a transformer than a dozen Level 2 ports combined, which is exactly why the phasing decision matters more for a depot than for almost any other commercial property type.
Decision 1: size the assessment and the application for the end state
Start the electrical infrastructure assessment and the utility service application around the fleet you expect to have at full buildout, not the fleet you are ordering this quarter. Two reasons make this the opposite of over-engineering.
The utility's timeline does not care how many vans you own today. A service upgrade or new transformer runs through the same will-serve review, the same design and pricing, and the same construction queue whether it is sized for 10 vans or 40. As of mid-2026 the country is still in a multi-year power and distribution transformer shortage driven by data-center demand and constrained production of grain-oriented electrical steel, with larger units running many months to multiple years and even routine distribution transformers stretching long in some territories (already covered in detail, with sourcing, in the electrical infrastructure assessment article linked above). If you ask the utility for a transformer sized for today's 8 vans, then come back in two years asking for a bigger one, you restart that queue from the beginning. Ask once, for the number you actually expect to need.
Distribution and conduit work do not shrink to fit a smaller ask, but they do get much more expensive to redo. The same logic that applies to a future-proofed retail installation applies harder at a depot: trenching a parking lot, running conduit to every charging stall, and building out panel or switchboard sections all cost meaningfully more as a second mobilization than as extra scope on the first one. The assessment should therefore answer two separate questions rather than one: what does the depot need today, and what does the site plan call for at full buildout, including stall count and the power level (Level 2 versus DC fast) each stall is meant to carry.
Decision 2: phase the equipment that is cheap to add later
The corresponding rule for the second half of the split: do not buy or energize charger hardware for vehicles you do not have yet. Chargers depreciate, warranties run on a clock from installation, and network and software subscriptions bill whether or not a vehicle is plugged in. The parts that are genuinely expensive to add later, mainly the conduit and the panel or switchboard capacity, should be sized for the end state; the parts that are comparatively cheap to add later, the actual charge points, should track vehicle arrivals.
In practice this usually means:
- Trench and conduit to every planned stall in the first mobilization, even the stalls that will not have a charger for two or three years. Leaving empty conduit in the ground costs a fraction of what it costs to reopen the same trench later.
- Build the panel, switchboard, or switchgear with spare breaker positions and bus capacity for the full stall count, not just the stalls being energized now. This is the same principle covered for any commercial site in switchgear and service equipment, and it matters more at a depot because the phased plan assumes you will come back to the same gear repeatedly.
- Install chargers only for the vehicles arriving in the current phase, leaving the remaining conduit runs capped and the remaining panel positions empty until the next batch of vans is ordered.
- Reassess the transformer at each phase rather than assuming the pad-sized unit from day one. The transformer pad and the primary conductors feeding it are worth sizing for the end state up front, since a pad and primary run are civil work with the same re-trench problem as conduit. The transformer itself, the actual kVA unit sitting on that pad, is a different story: it can often be right-sized to the current phase and upgraded later, since replacing a transformer on an already-built pad with existing primary service is a materially smaller job than the site work that would otherwise need to be redone. Confirm this sequencing with your utility during the service application, since some utilities prefer to set the full-size unit once rather than swap it later.
What a phased depot service application actually says
When you sit down with the utility's service planner, per the workflow in utility service applications and interconnection, a depot's load letter should show both numbers explicitly: the connected load for the phase you are building now, and the full build-out load the site plan anticipates, along with the timeline you expect between phases. This does two things. It lets the utility's engineers size feeder and transformer capacity, and any easement or civil work, for the number that will not need to be revisited. And it gives you a documented basis for the future phases, so the second and third rounds of charger installation are closer to a permit-and-connect exercise on infrastructure the utility already sized, rather than a second full application.
Two things commonly complicate this conversation, and it is worth raising both during the earliest planning call rather than after a load letter is submitted.
A distribution capacity study becomes likely once DC fast charging enters the plan. As covered in the interconnection article, a load in the hundreds of kW is far more likely to trigger a utility capacity study than a bank of Level 2 ports. A depot planning to add even a handful of 150 kW to 400 kW chargers in a later phase should expect that study to apply to the full buildout number, not just the phase in front of it, so budget the time for it up front.
Ask specifically about the utility's fleet or make-ready programs before defaulting to a standard line extension. Many utilities run a make-ready or new-business pathway aimed specifically at fleet and depot charging that changes who pays for the transformer and feeder work, similar in spirit to the utility make-ready programs covered elsewhere on this site. Availability, dollar amounts, and eligibility change often and vary by utility and by state, so confirm what is currently open in your territory rather than assuming a program you read about elsewhere still applies.
Load management changes the phasing math, and the code around it is moving
Load management is the single biggest lever for stretching a fixed service across a growing fleet, and it matters even more at a depot than at a retail site because a depot operator controls when vehicles charge. Overnight depot charging on predictable routes is close to the ideal case for a managed system: most vans return within a similar window, need to be full by roughly the same departure time, and do not all need full power simultaneously. Under NEC Article 625's energy management provisions, a listed system can stagger or cap the aggregate load below what the nameplate sum of every charger would otherwise require, which is often the difference between the service you have and the service a naive full-power calculation says you need.
The code language governing this is also changing in a way worth tracking if your jurisdiction is moving to the newest cycle. Trade-press coverage of the 2026 edition of the National Electrical Code describes a new section, numbered 625.48 in that coverage, addressing listing and monitoring requirements for EV energy management systems (EVEMS): the system would need to be listed, able to automatically hold the aggregate EVSE load within the site's available capacity, and able to log that data. That same coverage describes an exception that would remove the standard 125 percent continuous-load multiplier from circuits under a compliant EVEMS, since the system itself enforces the cap the multiplier otherwise protects against. Treat the section number and the exact requirements as reported, not independently confirmed against the published NFPA 70 text, until your electrician verifies them against the current code book. NEC adoption also happens state by state and typically lags the code's publication by a year or more, so confirm with your electrician and your local authority having jurisdiction which edition currently governs your project before assuming any 2026-cycle exception applies. Where it does apply, it is a meaningful lever for a depot squeezing a large, phased vehicle count onto a service that was sized once.
A worked illustration
Take a light-duty depot phasing from 10 vans to a planned 40 vans over three years, all on Level 2 charging at 7.2 kW per port with no DC fast charging in the plan.
- Nameplate load at full buildout: 40 ports at 7.2 kW is 288 kW, before any demand diversity.
- Managed load at full buildout: with vans returning on a similar overnight window and an energy management system staggering charge starts, a realistic managed peak might run 40 to 60 percent of nameplate, or roughly 115 kW to 173 kW, depending on how tightly the routes cluster and how much overnight window is available. This is illustrative math, not a substitute for the NEC load calculation your electrician runs against your actual routes and arrival times.
- What gets sized now: conduit and panel positions for all 40 stalls, and a transformer pad and primary run sized for the managed full-buildout figure above (with margin, since a distribution transformer under-sized for its final load is the more expensive mistake to fix).
- What gets phased: the transformer's actual installed kVA rating and the chargers themselves, added in step with the 10, then 25, then 40 van milestones, so the site never carries charger hardware or a fully-rated transformer for vans that have not arrived.
Swap in your own port power, route patterns, and phase timeline before using any of this for a budget; the shape of the split, not the specific kW figures, is the part that generalizes.
The bottom line
A fleet depot's electrical build is not one sizing decision, it is two, and conflating them is what produces both classic failure modes. Size the conduit, the panel and switchboard capacity, and the transformer pad for the fleet you actually expect to reach, because civil and utility-side work does not get cheaper to redo later. Phase the transformer's installed rating and the charger hardware itself to match real vehicle arrivals, because that equipment is comparatively cheap to add in the next round and expensive to carry idle in this one. Bring both numbers, current phase and full buildout, to the utility in the same application, and ask on day one whether load management or a fleet-specific make-ready pathway changes what the utility will require you to build.
Last factually verified: 2026-08-31 against NEC Article 625 reference material, trade-press coverage of the 2026 National Electrical Code's new EVEMS section (reported as 625.48; not independently confirmed against the published NFPA 70 text this session and flagged as such in the article), 2026 industry coverage of depot and fleet charging as the fastest-growing commercial charging segment and its push toward 150 kW to 400 kW DC fast charging (Ekoenergetyka, JointCharging, both vendor sources), and this site's own previously verified reporting on the 2026 U.S. power and distribution transformer shortage and utility interconnection workflow (see the linked electrical infrastructure assessment and utility service application articles for full sourcing on those points).
evcharginghelp.com is editorially independent and receives no compensation from any company mentioned.