How to identify how many items for a "PAT" test

When asked how many items to you have to be tested, when asked to price a job the understanding of what is considered a testable element is often misunderstood.  We also see examples on some sites where items perhaps were tested to ‘bump’ up the appliance count where items are being charged individually and actually may not have needed testing or where the risk would be considered to be so low it was not a consideration.

We generally say as a rule of thumb, that unless a risk assessment has been carried out and the recommendation to test additional items is deemed necessary.  We would only usually check items that directly plug into mains outlets, or consume mains power directly to operate.

This includes, computer towers and desktops, Laptop power supplies, mixing desks, fridges, extension leads, multiway outlets.


1 Item Test

This appliance features a fixed mains cable from the plug through to the actual item.

It is not detachable and therefore the item will be tested as 1 unit.

If any part of the item fails either a visual or combined test the whole unit will be withdrawn from service.  

All of the item will be subject to a full visual and checking of condition.

1 Item Test

This appliance features a mains adapter which converts the mains to low voltage (SELV) 

The primary test would be on the mains connecting equipment, and the subsequent fixed wire part emulating from it.  

Such things as copper wire exposed from the barrel plug would be a sign of damage and considered to be damaged.

IF the appliance were available we would provide a quick visual check to check for any obvious damage or danger and would advise accordingly.

2 Item Test

When testing items such as projectors and desktop computers they often have a detachable mains lead.  

Because the lead could be interchanged with another appliance we would test the lead as well.  We do this to check that the lead is ok.  If the item tested fine but the lead was damaged, this could pose a risk for the user, despite the appliance testing ok.

The lead would be subject to a test and the appliance would also be tested independently as they both handle mains voltage.

2 Item Test

A laptop with charger and mains cable is generally considered a 2 item test.  If the mains cable is detachable from the power supply then this could be interfaced to other appliances and if faulty could create a fault with the appliance it is plugged into.

The mains power supply is also tested and inspected right from the mains connector right through to the end of the low voltage (SELV) plug that goes into the laptop.   Typical failures include damage to the insulation when the plug is handled when unplugging from laptop.

The laptop isn’t generally tested however if available will be visually inspected for signs of damage to batteries, damaged case etc which could give rise to risk of fire or user injury.

IT is important to say that these are very rough guides and the individual environment, risk assessment and external factors may influence the number of items tested and identifiable to be tested.  If you have any questions, please send us a message!