Buying Guide - Generators

The Sealey Guide to Generators

Choosing the correct Generator for your needs is essential. If you get it wrong, the Generator can fail to provide adequate power for your needs and to use lead to sensitive equipment being damaged. But following our guide should lead to you making the correct choice for your requirements.


Your generator needs to be suitable to power the largest wattage appliance you intend using. If you plan to power two appliances simultaneously, you will need to use a generator capable of powering their joint wattages. The wattage rating can be found on either the specification label on the appliance, via the instruction manual or from the manufacturer. However, appliances fitted with induction motors, such as Pressure Washers, Vacuum Cleaners, Air Compressors, Freezers and Chop/Mitre Saws will have a starting voltage equivalent to three times their standard wattage rating. Finally, to ensure your Generator isn’t constantly working to its maximum output, add 20% to your total wattage figure.

So, if you have a Chop saw with a 600 watt rating and you plan to run 300 watt LED Work Lights at the same you’ll use the following calculation:

600 watt Chop Saw = 600 watt x 3 (to calculate its starting wattage) = 1800 watts

Plus 300 watt LED Work Lights = 300 watts

Sub Total = 2100 watts

Plus 20% = 420 watts

Grand Total = Minimum Generator output 2520 Watts        


Domestic or Professional

It is important you choose the correct Generator for your requirements. Some Generators are designed purely for light home and leisure use, while professional machines are designed for heavy duty trade and workshop use.


Sensitive Equipment

If you plan to provide power for sensitive electrical equipment, such as Televisions and Laptops, you will need to purchase an Invertor Generator. These provide a smoother power supply that won’t cause damage to delicate electronic components.


Power outlets

If you plan to use your Generator on UK construction sites, you will need a model that has 110 volt power outlets, as 230 volt equipment is not permitted under UK Health and Safety Regulations.


Generators are available with both petrol and diesel engines. This is an important consideration if all your vehicles run on one type of fuel, to prevent the risk of misfueling or you are a agricultural worker with access to red diesel.

View our current range of Generators here: