Load management and the DNO connection
The part of a commercial EV project that actually decides whether it is affordable — and how a load-management controller can save you an expensive grid upgrade.
Why the grid connection is the real constraint, not the charger
The chargers themselves are rarely the expensive part of a commercial EV installation. The cost and the timeline are driven by your electrical supply: how much spare capacity you have, whether you have three-phase power, how far the chargers are from the board, and — for banks of rapid chargers — whether you need a new grid connection at all. Get the connection strategy right and a workplace scheme can be a few days' work; get it wrong and you are waiting months on a Distribution Network Operator (DNO) and paying five or six figures for reinforcement.
This is exactly where an independent specialist earns its fee. An energy supplier or a general electrician will quote you chargers; we start with your incoming supply and your charging-demand profile, because that is what determines whether you need any grid work in the first place.
How dynamic load management works
Dynamic load management (also called load balancing) continuously measures your site's total electrical demand in real time and shares only the spare headroom across your active chargers. When the building draws more power — machinery, chillers, lighting — the chargers step down; when demand falls in the evening or overnight, they ramp back up. Nothing ever overloads the incoming supply.
The reason this is so powerful is diversity. You never size a supply for every socket drawing full power at the same instant, because in the real world they never do. The IET Code of Practice for EV Charging Equipment Installation (5th edition, 2023) is built around applying a simultaneity (diversity) factor and load management rather than raw connected load. In practice, often only 30-60% of your sockets are drawing power together, so load management lets you fit two, three or more times as many sockets to a given supply. A depot with a 24-van fleet can charge every vehicle overnight within its existing connection, staggered against the site's base load, without a single day of grid works.
A load-balancing controller typically costs between £100 and £450. Compare that to a single-to-three-phase supply upgrade at £3,000-£12,000, or a new high-voltage connection and substation for a bank of rapid chargers at £40,000-£200,000. Load management is usually the cheapest line item in the whole project and the one that saves the most.
DNO connection: notify or apply?
Every commercial installation involves your Distribution Network Operator — the regional company that owns the local electricity wires. There are two routes:
- Connect and notify (G98): for a single small AC charger where the additional load stays within roughly 13.8kW / 60A per phase on a single-phase supply, you can install first and simply notify the DNO afterwards.
- Apply to connect (G99): a three-phase installation, any DC rapid charger, a multi-charger scheme, or any site where total demand exceeds 60A needs a formal application that the DNO must approve before works begin. The DNO issues a connection quote within 5-65 working days depending on size, and you have 90 days to accept.
One important and little-known point: since 1 April 2023, EV chargepoint demand connections are no longer charged for network reinforcement (a change made through Ofgem's Access reforms). That removes the reinforcement cost — but not the reinforcement lead time. If your project would trigger reinforcement, you could still wait months for the network to be upgraded. Load management that keeps your declared demand within the existing capacity avoids triggering reinforcement altogether, which is often the difference between charging this quarter and charging next year.
Do you need three-phase power?
It depends on the chargers. A 7kW (32A) unit runs on a standard single-phase supply, which most smaller premises already have. A 22kW AC unit needs a three-phase (400V) supply, as do all DC rapid chargers. Many commercial and industrial sites already have three phase; if yours does not, you have a choice: upgrade the supply, or specify banks of 7kW units with load management — which for all-day workplace parking is usually the smarter, cheaper option anyway. (A 22kW unit rarely charges a typical car faster than 11kW, because most EVs cap their onboard AC charger at 7-11kW, so paying for 22kW is often paying for capacity the vehicles cannot use.)
Pairing with solar and battery storage
Load management also opens the door to on-site generation. Daytime workplace and fleet charging coincides almost perfectly with solar generation, so a solar array can power your chargers directly and cut both your cost per kWh and your grid demand. Commercial self-consumption often rises from 40-60% to over 70% once daytime charging is added, and past 80% with a battery. Note that solar or battery export is a separate DNO process (G99, or G98 for small systems) from the charger connection — we handle both.
Load management and connection FAQs
Do I need a three-phase power supply?
It depends on charger power. A 7kW (32A) unit runs on a standard single-phase supply, which most smaller premises already have. A 22kW AC unit needs a three-phase (400V) supply, as do all DC rapid chargers. Many commercial sites already have three phase; if not, you either upgrade the supply or specify 7kW units with load management. Confirm your incoming supply type and spare capacity before choosing charger speed.
Will my electricity supply and DNO cope with new chargers?
Any multi-charger or three-phase install should be checked with your Distribution Network Operator (DNO) before you commit. A single small unit may only need 'connect and notify' (G98), but most commercial sites — three-phase, multiple sockets, or total demand over 60A — need a G99 application approved before the chargers are switched on, typically 5-65 working days. Load management often lets you add chargers within your existing supply and avoid a costly upgrade.
How does load management actually work?
Dynamic load management monitors your site's total electrical demand in real time and shares the spare capacity across active chargers, throttling each so the incoming supply is never overloaded. When the building draws more power, chargers step down; when demand falls, they ramp back up. This lets you install more sockets than your supply could run at full power at once — exploiting the diversity factor — and often avoids an expensive DNO reinforcement. A load-balancing controller (£100-£450) is far cheaper than a supply upgrade.
Can we add solar panels to cut running costs?
Yes, and it's a strong pairing. On-site solar PV can power daytime charging directly, lowering your cost per kWh and grid demand — especially for workplace 7kW units used while the sun is up. Commercial self-consumption often rises from 40-60% to over 70% once daytime charging is added (80%+ with a battery). Note that solar or battery export needs separate DNO sign-off under G99 (or G98 for small systems), distinct from the charger connection.
How many charging sockets do we need?
Size to demand, not to the number of parking spaces. Estimate how many EV drivers — staff, fleet and visitors — need a charge on a typical day and how long each parks. Because not everyone charges at once, apply a simultaneity (diversity) factor; often only 30-60% of sockets draw power together. Load management then lets you fit more sockets to a given supply. Start with a sensible ratio and lay cable routes to expand cheaply later.