Workplace and Fleet EV Charging: What It Takes

What Does Workplace EV Charging Involve?

Workplace EV charging is a distribution project rather than a collection of chargers, and that distinction is the difference between an installation that works and one that has to be redone when the second phase arrives.

A single charger in a staff parking space is a dedicated circuit and not much more. Anything beyond that is different in kind. Multiple chargers mean a sub-panel or a dedicated distribution point, a feeder sized for the whole array rather than for one unit, a trench or a route across a parking area, and a decision about how the load is managed.

The load is the part that surprises people. Ten 40 amp chargers running simultaneously is a very large addition to a building's demand, large enough that on many sites it exceeds everything else the building draws. Sized naively, that is a service upgrade before a single car is plugged in.

Sized properly, with load management, it very often is not, and that is the single most useful thing to establish early. Working out the connected load is where that starts.

Most of the workplace charging we are asked about sits in the office parks and tradeports, around Pease International Tradeport and Portsmouth, Bedford, Nashua and Manchester, and in the Massachusetts parks at Andover, Methuen and Chelmsford.

How Many EV Chargers Does a Workplace Need?

Fewer than the number of EVs, and this is where most workplace schemes are over-specified.

A car parked at a workplace is typically there for eight hours or more. Even a modest charger replaces far more range in that time than most commuters use in a day, which means chargers can be shared across more vehicles than the naive one-per-car assumption suggests. Many workplaces run comfortably at one charge point per two or three regular EV drivers.

What matters more than the count is the management. Chargers that split available current between connected cars, a booking or queueing arrangement, or simply a culture of moving the car when it is done all multiply what a given number of points can serve.

The other half of the decision is growth. Installing for today's demand and being unable to extend is the common failure, because the expensive part is the distribution rather than the units. Running a feeder and a distribution point sized for the eventual array, then fitting chargers in phases, costs considerably less than doing the civils twice.

Does Workplace EV Charging Need a Service Upgrade?

Sometimes, and far less often than an unmanaged calculation suggests. The question is decided by the building's existing demand and by whether the charging load is managed.

Unmanaged, the arithmetic is unforgiving. Ten 40 amp chargers is 400 amps of potential demand, counted at 125 percent because it is continuous, on top of whatever the building already draws. On most commercial services that is a service upgrade.

Managed, it is a different calculation entirely. Load management caps the total the array can draw and shares it among connected vehicles, so the building sees a known ceiling rather than an uncontrolled addition. Cars charge a little more slowly when several are connected, which over an eight hour working day is almost always irrelevant.

There is also the timing question, which matters more on a commercial tariff than a domestic one. Charging that coincides with the building's existing peak can raise a demand charge that persists for the whole billing period, and shifting it is sometimes worth more than the energy cost itself. Establishing the existing demand profile before designing the array is the step that decides all of this. Service capacity and distribution work is where that starts.

Where Should Workplace Chargers Be Installed?

Close to the distribution if possible, and where the cars and the people actually are if not, and those two frequently conflict.

Distance from the panel is the largest cost driver on a parking area installation, because it drives cable size, trenching and reinstatement. A row of spaces against the building wall is a dramatically cheaper proposition than an island in the middle of a lot, and where a scheme is being designed from scratch that is worth weighing early.

Against that sit the practical considerations. Spaces that are visible and lit, since a charger in a dark corner of a lot is a charger nobody uses after four in the afternoon in December. Accessible spaces, which have their own requirements. Protection from vehicle strike, which in a busy lot means bollards rather than hope, and exterior circuits run as conduit and raceway rather than anything softer.

On a multi-tenant site there is a further question, which is whose spaces these are and whose meter they sit on, and in a managed building that is a metering and distribution question before it is a parking one. In an office park or at a tradeport with multiple tenants that is a lease question with a real electrical consequence, and it is worth settling before anybody trenches.

Who Pays for the Electricity at a Workplace Charger?

It depends on the arrangement, and deciding it before installation shapes what equipment is needed rather than the other way round.

The simplest arrangement is that the employer pays and treats it as a benefit. No metering, no billing, no administration. It works where the numbers are small and it stops working when they are not.

Where usage is to be recovered, the chargers need to identify users and record consumption, which means networked units and a back-end. That is a different product from a simple charge point and it carries an ongoing subscription as well as a higher capital cost, and it usually needs network cabling to each unit rather than power alone. Reselling electricity also has its own rules, which is worth checking rather than assuming.

The third arrangement, common in multi-tenant buildings and office parks, is that the charging load is sub-metered back to a tenant rather than to individual drivers. That suits a site where one tenant's staff are the users, and it keeps the administration at building level rather than per car.

Whichever applies, it is an equipment decision as much as a commercial one, which is why it belongs at the design stage.

Should a Business Install Fleet Charging or Staff Charging?

They look similar and they are designed differently, and a site that will eventually do both should be planned for both from the start.

Staff charging is unpredictable in timing and forgiving in duration. Cars arrive across a window, stay all day, and nobody needs a full charge by a particular minute. It suits shared points, load management and modest power per space.

Fleet charging is the opposite. Vehicles return together, often at the end of a shift, and they have to be ready by a known time the next morning. That makes the overnight window a hard constraint rather than a generous one, and it usually means more power per vehicle and a scheduling system that sequences charging through the night rather than all at once.

A site doing both needs to keep them separate in the design, because fleet vehicles charging on a schedule and staff cars charging opportunistically place very different demands on the same distribution. Workplace and fleet charging are the same infrastructure and different designs on top of it.

What Should a Business Plan Before Installing EV Charging?

The eventual size, the available capacity, the recovery arrangement and the route. Establishing all four before the first unit goes in is what makes the second phase cheap rather than expensive.

Eventual size matters most because it sizes the feeder and the distribution point, which are the parts that are disruptive to change. Installing two chargers on infrastructure built for ten costs a little more now and a great deal less later.

Available capacity decides whether load management is needed or whether a service upgrade is unavoidable, and that is a calculation on the building's real demand profile rather than on its service rating.

Workplace EV charging is one of the few commercial electrical projects where the building is likely to want more of it within a few years, which makes designing for the second phase the single most valuable decision at the first. We design and install workplace and fleet charging around Pease International Tradeport and Portsmouth, the office parks of Bedford, Nashua and Manchester, and across the border in Andover, Methuen and Lowell.