How many reefer trailers can a depot connection power?

It depends on how many reefer trailers cool down at the same time, not on the number of sockets. A trailer draws about 10 kW holding temperature and about 16 kW cooling down. Stagger the start-ups first; a business battery then covers the remaining peaks, so more trailers fit on the power your depot connection has.

Your trailers moved from the diesel to the plug, for the fuel and for the neighbours who complained about engines running all night. Then at five one morning the early shift pre-cools eight trailers for loading, and the main switch trips.

What is the power consumption of a reefer trailer on the plug?

On electric standby, a reefer trailer draws roughly 8 to 12 kW to hold temperature and 15 to 17 kW while it pulls down.

Figures: NOW GmbH, the German national centre for charging infrastructure (socket, 22 kW, diesel). ESL Power Systems, a supplier of reefer standby systems (pull-down and holding).

Your units may differ with the setpoint, the outside temperature and the load. A frozen load in summer asks more than a chilled load in winter, and defrost cycles and open doors add to that. A measurement at your own depot beats any table.

What does a 32 A reefer socket at the depot need?

A reefer trailer plugs into a three-phase CEE socket of 400 V and 32 A. According to NOW GmbH, that plug is the de facto standard for refrigerated transport, usable by most trailers on the road.

• 4-pole or 5-pole. Thermo King supplies power cables with a 4-pole or 5-pole 32 A plug. Units with a variable speed drive need a cable with a neutral wire, so check which plug your units use.
• Cable length. The manufacturer's cables come in 15 or 25 metres. Place the sockets so that a trailer at every dock reaches one without an extension.
• One circuit per socket. Your electrician sizes the cable and the protection of each socket under the AREI, the Belgian electrical code.
• Robust and outdoor-proof. Sockets on a dock take knocks, rain and trailers that drive off still plugged in.

Adding sockets along the dock is the easy part; the connection behind them, sized for the building, is the limit. Ten sockets of 22 kW add up to 220 kW on paper, more than many depots have in total.

How do you calculate how many reefer trailers your connection carries?

Divide the power your connection has left by what the trailers draw at your busiest moment.

An illustrative example, not a customer case: a depot has about 150 kW available on its connection. Offices, lighting, a cold room and forklift chargers use about 50 kW early in the morning, leaving 100 kW for eight reefer trailers.

The same eight trailers ask 80 kW or 128 kW, depending only on timing. A depot with twelve sockets can be fine; one with six can trip every Monday.

When do reefer trailers draw the most power at a depot?

At a typical food distribution depot, the peaks come twice a day: when trailers come back and when they are pre-cooled for loading.

Night distribution, trailers parked over the weekend or a cold store that uses trailers as extra storage put the peaks elsewhere. Your quarter-hour data shows exactly when. Size on your busiest morning, not on the average day: that is where a depot trips or holds.

The quiet hours in between make a battery work. When most trailers are out, it recharges from the grid or from solar panels on the warehouse roof.

Why does a reefer peak cost you money even when nothing trips?

Because business grid tariffs charge the highest power you draw, not only the energy. One morning in which eight trailers pull down together can set your peak for the month.

In Flanders, on a low-voltage connection with a digital meter, the capacity tariff takes the average of your last 12 monthly peaks. In 2026 it costs about 53.39 euro per kW per year on average (excl. VAT). Larger sites pay for their peak power in their own tariff; the principle stays the same.

Want to read your own peaks? How to calculate the capacity tariff for your business explains it, and what drives the peak demand of a business shows what else sets them.

The bigger risk is a trip at the wrong moment. If the main switch cuts out at night, every trailer on the plug stops cooling, and so does your cold room. For that side of the cold chain, read how long a battery keeps a cold room cold in a power cut.

Should your depot stagger the trailers, add a battery or get a heavier connection?

Start with the cheapest step and only move on when the numbers ask for it. Most depots need a combination.

• 1. Stagger the start-ups. A load controller switches the sockets on one group at a time, or holds back new pull-downs while the site is busy. Cheap, but trailers wait their turn.
• 2. Add a battery. It covers the pull-down peaks that staggering cannot remove and recharges in the quiet hours. The grid sees a fixed limit.
• 3. Request a heavier connection. Needed when the trailers fill most of your connection even while only holding temperature. It takes time, and in some areas the grid operator postpones it.

In a Victron system, peak shaving keeps the grid offtake of the whole site under a current limit you set. The battery covers the trailers and the building above that limit, as long as it has charge.

A farm in Tielt shows the principle. Its connection was too small to grow; a battery system now gives the site more power without a heavier connection.

Did the grid operator refuse or postpone a heavier connection? Read your options when a heavier connection is refused.

Weighing a medium voltage cabin against a battery? A high-voltage cabin or a battery compares the costs; what peak shaving is and when a battery pays off gives the sizing logic.

What changes with electric reefers and electric trucks?

Fully electric reefer trailers carry their own battery, but they still need the socket at the depot. And electric trucks add a much larger load on top.

• Electric reefers. According to NOW GmbH, the newest trailers replace the diesel unit with a high-voltage battery of typically 30 to 40 kWh, good for a few hours up to a working day of cooling. Longer stops need external power, usually through the same 32 A CEE plug.
• Recharging those batteries. An electric reefer that comes back half empty charges its battery and cools at the same time, so the evening peak at the socket gets longer, not shorter.
• Electric trucks. A truck charger asks far more power than a reefer socket. Our article on charging electric trucks at your depot covers that case.

Plan the depot connection for where the fleet is going, not only for today. A battery sized for the reefer peaks can later buffer truck charging too, if the design allows for it from the start.