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What Size Generator Do I Need to Run a Catering Trailer's Fridges and Freezer?

by Bee
(Sussex, UK)

Black twin-axle catering trailer with an open serving hatch at a UK outdoor event

Black twin-axle catering trailer with an open serving hatch at a UK outdoor event

Hi everyone,

I really hope you can help me!

I have recently bought a 10ft x 7ft mobile food trailer and now, most recently am now trying to get everything up and running by myself and really struggling with powering the electrics

The trailer is stored about a 4 minute drive away - but there are no electric hook ups there and after researching, there are no local storage facilities that offer this.

The trailer has storage for and uses 2 x 19kg LPG cannisters and the main griddle and Bain Marie are run off of this.

However, to be able to work the trailer for my menu and safely store food, I need:
- A full freezer (already included with the trailer)
- A slimline fridge (Meat Fridge) - already included with the trailer
- A full undercounter fridge (Dairy, Salads, drinks etc...) which I have to yet buy.
- Buffalo Hot Water Urn - already included for hot drinks and water for washing/cleaning
THESE ARE ALL RUN OFF OF ELECTRICS

- I also have/need:
- a small 2 slice toaster
- A 9l Air Fryer
- Tilling system
- Phone charger

- I also have 2 single burner gas stoves to use.

- I only have 4 x double sockets - 1 needed for Urn, 3 for fridges and freezer

I will be using electrical cool boxes to transfer fridge/freezer food to and from home each day, where the food will be stored

POWER
I am VERY CONFUSED about START UP AND RUNNING WATTS and have been told several different things regarding the size generator I need.
- Immediate turn on - urn, fridges, freezer, light, tilling system.

GENERATORS
Some say I need a 6000W, some 8000W. I need it to be silent, easy to use and portable (Manageable and manual handling for myself). Some have also mentioned Leisure Batteries.

MY CONCERN:
- The freezer will take 8 hours to get to temperature - and I can't keep things for freezer that cold for that long!

Basically, can I SAFELY power the freezer and/or meat fridge overnight using a power source - to not only reduce the transportation of goods to and from home but also TO REDUCE THE START UP WATTS needed for the generator?

I would honestly appreciate ANY ADVICE as getting a bit desperate as I need to be up and running within the next 2 weeks!!!



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Jul 23, 2026
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by: MobCater

Bee, you have landed on the trickiest part of running a trailer, and the fact that you are asking before you spend tells me you will get it right. Let me take some of the worry out of it.

The confusion over start-up and running watts is completely normal. Fridges and freezers have a compressor that pulls a big surge the moment it kicks in, often two or three times its running figure, so the generator has to cope with that spike on top of whatever else is already running. That is why you keep hearing different numbers. Add up the running watts of everything you would ever have on at the same time, then make sure the generator can swallow the largest single surge on top of that. In practice a good quiet inverter generator of around 3.5 to 5kVA will run a full freezer, a couple of fridges, your lights and till very comfortably. The reason some folk jump straight to 6000 or 8000 watts is the Buffalo urn and the air fryer, which are hungry, so if you run those alongside everything else you need the headroom. My honest steer is to stagger the big draws rather than buy a generator so heavy you cannot lift it, and look for an inverter type, as the cleaner power is kinder to fridge compressors and far quieter.

Now the part that matters most for your peace of mind. I would not leave a generator running overnight, and never unattended at a storage yard. It is a fire and fume risk, it is noisy for anyone nearby, and most insurers and councils will take a dim view of it. A leisure battery and inverter can hold a single fridge for a while and is brilliant for lights, but a full freezer overnight will flatten anything short of a serious battery bank, so it is not quite the answer you are hoping for.

Since your freezer takes eight hours to reach temperature, do not rely on switching it off and on. The cleaner route is the one you have half planned already, keep your frozen and chilled stock at home in a proper freezer and fridge, and carry it in and out each day in your cool boxes. Run the generator, or a battery setup, only while you are trading. Hold cold food at 4 degrees C or below and frozen at minus 18, and a cheap digital thermometer in each unit will tell you at a glance that you are safe.

The one job I would never do myself is the wiring. Get a qualified electrician to fit the trailer's sockets and RCD protection so the generator feeds it safely.

You are thinking about this the right way, and once the power is sorted the rest falls into place. The temperature logger in the app (Toolkit tier) keeps an EHO-ready record of your fridge and freezer readings, and when you are ready to price up a quiet generator the reviews on mobcater.com will save you a few false starts.

All the best

David

Disclaimer: Electrical work on a catering trailer should be carried out by a qualified electrician, and food safety rules can change. Always check the latest FSA guidance and speak to your local Environmental Health Officer about safe food storage before you start trading.

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