If you are a facilities manager or estates director planning workplace EV charging, the most expensive mistake you can make is installing infrastructure that cannot scale. The cost of retrospective cable upgrades, additional DNO applications, and disruption to an operational car park is typically 3-5 times the cost of getting the infrastructure right from the start.
This guide covers the planning decisions that determine whether your EV installation scales smoothly or requires costly rework within 2-3 years.
Why "Start Small" Often Creates Costly Rework
The instinct to start with a small pilot installation is understandable. Demand is uncertain, budgets are constrained, and the technology is evolving. But a pilot installation planned without future capacity in mind creates problems:
- Cables sized for 4 charge points cannot support 20 without replacement
- A distribution board installed for current demand has no spare ways for expansion
- A DNO connection agreed for 50kW cannot be upgraded to 200kW without a new application and potentially significant reinforcement costs
- Cable routes through a car park that are trenched and reinstated once will need to be trenched again for additional runs
The solution is not to install everything at once — it is to plan the infrastructure for the full build-out and install the active equipment in phases. This is the difference between infrastructure-first planning and equipment-first planning.
Assessing Power Capacity
Every EV installation starts with a power capacity assessment. The key questions:
Maximum demand assessment: What is the current maximum demand on the building supply? How much spare capacity exists? A maximum demand assessment by a qualified engineer establishes the baseline. Do not rely on theoretical calculations from the original building design — actual demand may be significantly different.
DNO application: If the existing supply cannot support the planned EV load (even with load management), a DNO application for supply upgrade or new connection is required. DNO lead times are typically 3-6 months for standard connections and 6-18 months where network reinforcement is needed. Start this process early — it is almost always the longest lead item in an EV programme.
Load management: Dynamic load management distributes available power across active charge points based on real-time demand. This allows more charge points to be installed than the supply could support if all were charging simultaneously at full power. Load management is not optional for most workplace installations — it is the mechanism that makes the economics work.
Infrastructure-Scale Programme Management
Our multi-site delivery for Vattenfall demonstrated infrastructure-scale electrical programme management — the same discipline applied to workplace EV rollout programmes.
Smart Charging Regulations
The Electric Vehicles (Smart Charge Points) Regulations 2021 apply to all new charge point installations in workplaces. Key requirements:
- Charge points must have smart functionality — the ability to send and receive information, respond to signals to increase or decrease charging rate, and provide demand-side response capability
- Charge points must meet the OCPP (Open Charge Point Protocol) standard or equivalent, ensuring interoperability and preventing hardware lock-in to a single network provider
- Charge points must have a default off-peak charging schedule (though this can be overridden by the user)
- Charge points must measure and record electricity consumption
OCPP compliance is particularly important. Charge points that use proprietary protocols lock you into a single network provider for the life of the hardware. If that provider changes their pricing, service quality, or goes out of business, you have no option to switch without replacing the hardware. OCPP-compliant charge points can be managed by any compatible network provider.
Phased Installation: Infrastructure First
The most cost-effective approach for workplace EV charging is to separate infrastructure from active equipment:
Phase 1 — Infrastructure: Install the full cable infrastructure, distribution boards, and containment for the planned maximum build-out. Size cables, protective devices, and earthing for the full load. Install ducts and draw pits in the car park for future cable runs. This is the expensive, disruptive part — do it once.
Phase 2 onwards — Active equipment: Commission charge points in phases as demand grows. Each phase connects to pre-installed infrastructure and requires minimal additional civil or electrical work. Adding 4 charge points to pre-installed infrastructure takes days. Adding 4 charge points where no infrastructure exists takes weeks.
This approach means the car park is trenched once, the building supply is upgraded once, and the DNO application covers the full build-out. Each subsequent phase of charge point installation is a simple connection exercise. Programme progress and phase completion can be tracked through Contracts OS, providing estates teams with real-time visibility of the rollout.
OZEV Workplace Charging Scheme
The OZEV Workplace Charging Scheme provides a grant of up to 75% of the cost of purchasing and installing charge points, capped at £350 per socket (up to 40 sockets per applicant). Key eligibility requirements:
- The applicant must be a registered business, charity, or public sector organisation
- Charge points must be installed at a workplace parking facility
- Charge points must be smart and meet the minimum technical specification
- The installation must be carried out by an OZEV-approved installer
- The grant covers the charge point unit and installation labour — not infrastructure works (distribution boards, cable runs, civil works)
The grant is useful but should not drive the specification. Selecting charge points primarily because they maximise the grant rather than because they meet the technical requirements of the installation is a false economy. The grant covers a fraction of the total programme cost — the infrastructure investment is the significant element.
Common Mistakes to Avoid
- Undersized cables — installing cables sized for current demand rather than planned maximum capacity, requiring replacement when demand grows
- Non-OCPP hardware — selecting charge points with proprietary protocols that create vendor lock-in
- Ignoring DNO lead times — starting the DNO application after the installation programme has been committed, creating programme delays
- No load management — installing charge points without dynamic load management, limiting the number that can operate simultaneously
- Equipment-first planning — selecting charge point hardware before assessing power capacity and infrastructure requirements
- Single-phase only — installing single-phase infrastructure when three-phase is available and would support faster charging and better load distribution
Planning Checklist
Before committing to a workplace EV charging programme:
- Commission a maximum demand assessment of the existing building supply
- Define the planned maximum build-out — how many charge points will the site need in 5 years?
- Start the DNO application process if supply upgrade is required
- Specify OCPP-compliant charge points to avoid vendor lock-in
- Design infrastructure (cables, distribution, containment) for the full build-out
- Plan phased commissioning of active equipment aligned to demand
- Confirm OZEV grant eligibility and include in the business case
- Appoint a contractor who can deliver both the electrical infrastructure and the charge point installation under a single contract
The decisions you make at the planning stage determine whether your EV infrastructure scales efficiently or requires costly rework. Infrastructure-first planning costs marginally more upfront but eliminates the retrospective works that make under-specified installations significantly more expensive over their lifetime.
For more on our approach to EV infrastructure, see our EV infrastructure services. For how EV charging connects to fleet electrification and carbon reduction, see our sustainability commitment.