Electricity Supply Advice

Guide to electricity supply for commercial catering appliances

Catering Appliance Superstore recommends getting an electrician to advise on purchases of high powered electrical appliances, or those which are hardwired (i.e without a three pin plug), but it certainly doesn't hurt to know as much as you can about the supply of electricity to your commercial appliances. For hands on customers who like to know what exactly is what, we have produced this plain English guide to electricity supply in the UK and what that means for the installation of commercial catering appliances. Spending ten minutes reading the guide will save you time when it comes to comparing appliances and prices - some you will be able to rule out immediately based on the stated power requirements and what you know about your own electricity infrastructure.

There are two main things to check - whether you have sufficient Amperage on the circuit you want to install your commercial appliance on, and the type of supply you have, single phase or three phase. We will take you through the following easy to understand sections.

  • Amperage requirement of your commercial catering appliance
  • Amperage rating of your circuit
  • Spare circuit capacity
  • Hardwired catering appliances, circuit breakers and fused plugs
  • Voltage of supply to your property; single phase and three phase power

Amperage requirement of your commercial catering appliance

You will need to check the Amp rating of the machine you are buying, and check this against the Amp rating and current usage of the circuit you wish to install it on, to ensure you have sufficient power for the machine. If you get this wrong you will constantly trip the circuit breaker.

The power input requirements of machines sold by Catering Appliance Superstore are expressed in terms of Volts and Watts, and the required supply on the circuit you will install the warewasher is expressed in Amps. The relationship between the three, in very basic terms, is:

  • Volts - unit of electric potential - how much power the machine draws from the mains supply when activated (a bit like water pressure when a tap is turned on).
  • Amps - unit of electric current - the strength of the power the machine draws.
  • Watts - unit of electric power - sum of Volt and Amps, the total electric energy being used, the amount of work being done by the machine.

The appliances you purchase from Catering Appliance Superstore will have information on the input they need to run and their total power usage. For example, the Hobart Ecomax G402 Glasswasher draws 230 Volts, and its total power usage is 2200 Watt (or 2.2 Kilowatt). Dividing 2200 watts by 230 Volts gives an Amp rating of 9.56, so the Hobart Ecomax G402 will need a 9.6 Amp supply, and the circuit you install it on will need to have spare capacity for it.


Amperage rating of your circuit

The electricity supply to your property is expressed in terms of Amps or Amperes (the strength of electric current). For example, 60 Amps used to be considered a healthy supply, but modern properties with modern appliances use more electric current to power them (they're doing more work overall) and are generally on a 100 Amp or even 200 Amp supply. Check with your electricity supplier if you aren't sure.

The total supply is broken down into separate circuits at your main circuit board - for example, one for upstairs lights, one for downstairs lights, one for downstairs power sockets, etc. You might even have multiple circuit boards, particularly in a commercial property, with their own mains supply.

Each circuit has a share of the total Amperage supply to your property and has its own circuit breaker, something that cuts the supply if that circuit is overloaded. For example, the downstairs power sockets might be on a 15 or 20 Amp circuit. Generally, the circuit is labelled at the circuit breaker, on the circuit board (also known as a distribution board).


Spare circuit capacity

Determine how much load you already place on the circuit you intend to install your commercial catering appliance on, by calculating the amount of Amps already drawn by the other appliances on the circuit. Obviously, you'll need to know which sockets are on the circuit, what gets used by your staff in those sockets, and whether anything is hardwired in to the circuit as well (so you might need an electrician's help, or refer to up-to-date wiring plans if you have them).

Check the Amp rating (strength of current) of each appliance, by checking the nameplate of the appliance. If the Amp rating isn't shown, look for the Wattage (that's the total energy it uses) and divide this by the Voltage of your electricity supply. Unless you are on three phase supply (see next section) this will be 240 Volts (strictly speaking UK supply is classed as 230 Volts with a margin of error of -6% or +10%...but most properties are on 240 Volts).

For instance, an iron might have a Wattage rating of 1200, and a really inefficient hairdryer might use as much as 1800 Watts. Dividing the total of 3000 Watts by 240 Volts gives you a requirement for a 12.5 Amp current. So our 15 Amp downstairs socket circuit can handle both of these running at once, but probably not very much else (before the circuit breaker is tripped).


Hardwired catering appliances, circuit breakers and fused plugs

Every appliance needs to have a fuse or circuit breaker safety mechanism, which cuts the supply of electricity if the machine or the circuit starts to draw more power than it can handle (in case of a fault in a commercial appliance, for instance, or if too many appliances are plugged into a single circuit). This is to prevent electrical fires and risk of electrocution.

Catering Appliance Superstore products clearly show the type of supply and the protection provided, whether this is a plug-in (and if so what Amp fuse is required, always greater than the Amp rating of the product but as close to it as possible), or if it needs to be hardwired in to the circuit.

Hardwired catering appliances are protected by the circuit breaker for the circuit they are on. You will need an electrician to install a hardwired appliance to the power circuit, and once installed it obviously won't be easily movable to a new location, so choose positioning carefully and consider provision of other services like hot or cold water, drainage, and fume extraction.

It might seem like a lot of extra effort to fit a catering appliance with a hardwired connection, but it can really be worth it for larger machines. Hardwired connections have far less electrical resistance than plug connections, meaning they are more energy efficient, and they are less susceptible to damage and wear over time - there is no corrosion or weakening of contact points to further increase electrical resistance or cause a hazard.


Voltage of supply to your property; single phase and three phase power

As well as an Ampage (current strength) rating, the electricity supply to your property is also expressed in terms of Voltage. For most UK domestic and commercial properties up to a significant size, the only two options available are single phase or three phase, which will generate either 230 Volt or 400 Volt supply respectively - though most UK supplies actually get 240 Volt and 415 to 420 Volt, and appliances are still built to cater for the higher limits.

Alternating current power supplies are transmitted in waves of alternating magnitude and direction. Three phase supply simply uses three single waves that are out of phase by one third of a cycle, so they peak in quicker succession.

Three phase supply delivers more electrical energy than single phase, and commercial catering appliances with high energy requirements will be wired for three phase to take advantage of this. Three phase options are available in many of Catering Appliance Superstores ranges - if you have a three phase supply you will be able to purchase a more powerful machine, fitted with a very simple high powered motor that will last for a long time (they're also usually cheaper to produce than single phase motors).

For example, most of the DC glasswashers stocked by Catering Appliance Superstore are available in 240 Volt single phase, but for some larger capacity models, 415 Volt three phase options are also available.

By Philip Wearmouth | Catering Appliance Superstore