Electricity voltage can be a confusing issue, especially when half the world uses 110 volts and rest uses 200 / 240volts, such as the UK. There are times when this can be a problem, for example, when goods are purchased from a different country or simply when travelling. The solution is a voltage transformer, also known as an electrical transformer.

What is a Voltage Transformer?

A voltage transformer, also known as voltage converter, electrical transformer or power converter, is an electrical device that converters the electrical output of a power source - it either reduces or increase the voltage out of the mains. The most common use is for changing the voltage from 240volts down to 110 volts, or up from 110 volts to 240 volts.

A voltage transformer allows an appliance designed to be run on one type of voltage to be used on another, for example, designed to be used on 110v can be used on a 240v.

Which Type Voltage Transformer is required?

A voltage transformer can either be a step-down transformer or a step-up transformer.

Step-down transformer: If you are using electronics or appliances that were purchased in a country with 110 volts (e.g., USA) and wish to use them in country with 220/240V power, a “step-down converter” is required.

Step-up transformer: If you are using electronics or appliances that were purchased in a country with 220/240V (e.g., UK) and wish to use them in a country with 110 volts, a “step-up converter” is required.

We stock a range of step-up and step-down converters available in sizes up to 2000 watts.Click here to see our selection of Voltage Transformers.

How to determine the size of electrical transformer required?

The size of a voltage transformer is defined by wattage. Therefore, the wattage of the device/appliance that you will be powering needs to be established to determine the size of the transformer required. 

The wattage of the item can normally be found on a label on the item describing the power rating or in the user manual.

Note: The wattage of the time may be abbreviated to ‘Watts’ or ‘W’. 

If the power rating is not specified it can be calculated from the following equation:  Watts (W or VA) = Amps (A) x Volts (V).

If only the amperage (amps) are displayed, multiple it by the volts to find the wattage, for example, 2A x 110V = 220W

Once calculated, choose a voltage transformer which can handle a higher amount of wattage that your device is rated. Please note that if the appliance is motor based, it may require additional power to start up than is indicated (this is known as surge), as a guide add 20% to the power requirements of the device or contact the manufacturer of the appliance for further information. It is good to remember, that a transformer with a higher rating will not harm your device.

Example of problem a voltage transformer solves:

A product from the USA which runs on 110V, is to be used in the UK at 240V. The product has a wattage of 454watts. 

• If an appliance was designed for use in the USA, it will run on 110V.
• The power from the sockets in the UK is 240V.
• The item is plugged into a 500VA step-down transformer, which changes the voltage down from 240v to 110V.

What happens when a product is dual voltage?

A dual voltage device means that it accepts both 110-120V and 220-240V rated input power. Luckily many travel gadgets are duel voltage, so you will only need to use a travel adapter, also known as a plug adaptor. 

A foreign plug adapter does nothing to the power, it literally changes the physical plug type. The type of travel adapter required will depend upon where you are travelling to or where the product is from. Please click here to view our range of travel plugs.