An electric fleet often grows one vehicle order at a time. The civil and electrical infrastructure serving the depot is harder to expand in small increments.
Adding another charger can mean reopening a cable trench, working around parked vehicles or cutting across an access route that the depot cannot close. For operators planning several rounds of electrification, those disruptions deserve attention during the first design phase—not after it. If your depot’s charging requirements still need to be quantified, start with our guide to reassessing depot charging capacity. It covers vehicle demand, charging windows and available site power. This article focuses on how to stage construction once those requirements are understood.
Planning for Growth at Oakleigh Depot
ComfortDelGro Australia’s planned Oakleigh depot electrification provides a recent example of infrastructure designed to accommodate fleet growth.
Works are scheduled to begin in November 2026 in partnership with EnergyAustralia. Once complete, the depot is expected to support more than 77 battery-electric buses, with infrastructure designed to accommodate up to 85. The scope includes grid upgrades, switchboards, charging power units, vehicle chargers, and related electrical and civil works.
The announcement does not disclose how procurement or construction will be divided into phases. It does distinguish the expected operating fleet from the infrastructure’s planned capacity—which is the core decision any operator faces when the fleet will grow over time.
Read ComfortDelGro Australia’s Oakleigh depot announcement.
Start With a Phased Site Plan
Before deciding what to purchase or pre-install, map the expected stages of fleet growth onto the depot layout.
The first stage may serve a confirmed vehicle order. A later stage may depend on contract renewals, replacement cycles or what the first phase reveals in practice. Those stages carry different levels of certainty. Provisions for a speculative third phase need a different justification from infrastructure required for vehicles already ordered.
A useful phased plan shows which bays are needed now, which areas are candidates for the next conversion, and which spaces might support longer-term growth. It also identifies access routes that must stay open through each construction stage. Getting this on paper early exposes conflicts—a proposed future charging area that doubles as maintenance access, for example, is better found on a drawing than during construction.
Prepare Underground Routes for Later Installation
Civil works warrant early attention because later changes can disrupt an operating depot.
Where the next phase is reasonably well defined, it may make sense to install spare ducts or draw pits during the initial groundworks. The value depends on where the route runs. Reopening a quiet perimeter strip has different consequences from cutting across the only entrance to a loading bay. Before approving these provisions, confirm where future equipment is likely to sit and whether the proposed route can support the intended installation. Duct sizing, cable requirements, separation distances and installation conditions all need to be reviewed by the electrical designer.
Document what is installed. Accurate as-built drawings and clearly identified spare ducts have practical value when another contractor arrives several years later. An undocumented provision can be overlooked or accidentally modified.
Reserve Usable Space for Electrical Equipment
Space marked as reserved on a drawing needs to remain available as the depot evolves. Future charging equipment requires more than its cabinet footprint—foundations, protective barriers, maintenance clearances and cable entry points also need space. A location that looks free today can become a storage area or an additional parking bay without anyone explicitly deciding to use it. Recording the intended purpose in the site plan, and making sure the operations team knows, reduces the risk of that space disappearing before it is needed.
Switchgear deserves specific attention. Depending on the design, provisions may include space for additional sections, spare outgoing ways or an enclosure sized for later additions. The designer should identify what each provision enables and what further work would still be required. An empty position in a distribution board does not mean the depot has sufficient supply capacity to connect another charger—future cabling, protection and utility work may still be needed. The project documentation should state those limits clearly.
Align Grid Work With the Fleet Programme
Utility work can follow a different timeline from charger procurement, and that gap causes delays when it is not managed as a dependency.
Where additional supply capacity will be needed for a later fleet phase, discuss the requirement with the utility and electrical designer early. Connection approvals, equipment lead times and any reinforcement works need to be considered alongside the vehicle delivery schedule. If the second vehicle order depends on an electrical upgrade, that upgrade needs its own milestones—it cannot be treated as a task to arrange once the vehicles are confirmed.
Securing the full anticipated connection capacity at the outset may be justified for some depots, but the decision should reflect the credibility of the growth plan, connection costs and applicable tariffs. Where growth remains uncertain, record what would trigger the next utility review—a confirmed vehicle order, a new operating contract or a change in the site’s development plans.
Buy Charging Equipment in Stages
Preparing a site for future expansion does not require purchasing every charger at once. Later equipment purchases can be aligned with confirmed vehicle deliveries and assessed against those vehicles’ requirements, which also gives operators a chance to apply lessons from the first phase before committing to the next round of hardware.
Procurement lead time still matters. Equipment delivery, installation and commissioning need to be scheduled ahead of vehicle deployment. A deferred purchase should have a defined timetable, not just a decision to spend later.
If a proposal relies on adding power modules, terminals or other components later, ask the supplier to explain the supported expansion path in writing—what can remain, what must be added or replaced, and whether existing equipment needs to be taken offline during the upgrade. Product families change, and compatibility assumptions made during initial design should be checked against the supplier’s documented configuration and support commitments before each later purchase.
Keep the Depot Running During Later Construction
Future expansion will be easier to deliver if the next construction phase is thought through while the first one is being designed. Later installation work will need contractor access, delivery routes and temporary barriers, and may require electrical isolation or temporarily closing certain bays. Reviewing that scenario with the operations team during initial design is straightforward; resolving it during a live construction phase is not.
Work through which bays become unavailable during construction, whether vehicles can still reach their assigned chargers, and which activities would need to move temporarily. In some depots, placing equipment so it can be accessed from the perimeter simplifies later works considerably. In others, cable routes or available space lead to a different arrangement. Either way, the output that matters is a workable sequence: where contractors enter, what can be isolated, and how the fleet continues operating while the next phase is built.
Separate Current Works From Future Provisions in the Quote
A phased project is easier to evaluate when the quotation distinguishes what is needed now from what is being proposed for later. Ask the project team to break out the equipment and works required for the confirmed fleet, any enabling works proposed during the first construction phase, and what is being deferred to subsequent phases.
For each early provision, request a brief explanation of what it enables and what remains outstanding. A spare duct may avoid reopening a section of yard; a reserved equipment area may preserve installation access—but neither removes the need for additional cabling, electrical protection or utility work when the time comes. This breakdown helps the operator judge whether an early investment is justified, and gives the next project team a clear record of what has been prepared and, just as importantly, what has not.
Discuss Equipment With Injet
When reviewing DC charging equipment with Injet, share the intended installation stages alongside the initial vehicle requirements. Useful inputs include the confirmed vehicle order, expected timing for later phases, the proposed bay layout, electrical design constraints and any restrictions on future construction access.
The Injet Ampax DC charger range can be assessed as part of that discussion. Any assumptions about future expansion should be confirmed for the specific configuration and phase.
Explore Injet Energy’s fleet charging solutions or contact the team to discuss your planned deployment.