Working Standards

The working standards document is designed to assist members of the Portable Appliance Testing Trade Association (PATTA) to explain the methods and standards expected of an association member. The working standards provides a reference to assist in raising standards and improving the reputation of the Portable Appliance Testing Industry.

The objective of the standard is to provide advice and information to its members and to recommend a minimum standard, which every member is expected to adhere to.

General Standards

Competence and Qualifications

The association does not insist on any member holding a specific qualification, but it is expected that members be competent when joining the association. All members must understand that they will be representing PATTA when they carry out the inspection and testing of electrical equipment (PAT Testing). It is therefore essential that members have enough skill and knowledge to be able to complete the appropriate activities.


Association members will need to have access to a suitable PAT instrument or another piece of equipment such as a 17th Edition installation tester to be able to complete the inspection and testing.

PATTA will not impose any brand or type of testing machine to be used, but members should make sure they have access to a machine suitable for the work they are performing.

Contact with Customers / Quotations

The customer has a right to expect a professional service from the member, from the first point of contact and finishes once the work has been completed.

Branded Clothing

There is no requirement to wear branded clothing however, it is recommended that members add the PATTA logo to their own workwear.

Inspection and Test Procedures

PATTA acknowledges that members have their own inspection and test procedures, in addition to their own preferred method of working and therefore does not intend to enforce any preferred method of working. However, the test processes used by the member will need to comply with the spirit and objectives of the current edition of the IET Code of Practice for In-service Inspection and Testing of Electrical Equipment, (ISBN: 978-1-84919-626-0) as well as Health and Safety Executive guidance and industry best practices, shared and promoted through the Association.

Visual Inspection

All appliances must be given a thorough visual inspection comprising of an in-depth check of the visual integrity of the plug, fuse, cable and case of the equipment under test.

Mains Plug

The mains plug inspection requires the plug to be opened (if it is a normal re-wireable type) and a check completed that the correct fuse is fitted, terminal screws are tight and wired correctly.

Plug Fuse

Part of the visual inspection requires a check to ensure that the plug fuse meets British Standards and is the correct rating for the appliance. BS1363 has standardised on just two preferred fuse ratings, 3-amp and 13-amp, however any fuse rating up to 13-amp can still be used.

Plugs for appliances rated up to about 700 watts should have a 3-amp fuse (coloured red).
Plugs for appliances rated between about 700 watts and 3000 watts (the maximum rating of a wall socket) should be fitted with a 13-amp fuse (coloured brown).

Counterfeit and Non-UK Standard Appliances

A growing problem is the number of counterfeit and ‘fake’ items, which are finding their way into UK businesses. Members of the association should be able to detect and identify counterfeit items and should be expected to keep updated on current warnings and guidance. Updates are available on various sites (, and members are encouraged to share information about non-standard items they find through the PATTA Forum. (

Class I Appliances

A piece of electrical equipment should be tested as a Class I appliance, if there is no additional information shown on the information/rating label.

Class II Appliances

Class II equipment should bear the double square symbol. If the symbol is not visible, then the appliance should be tested as Class I equipment.

Mains Cord Sets and Multi-way Extension Leads

Enough socket outlets should be provided so that multi-way adaptors and extension leads are not necessary however all mains power and multi-way extension leads should be given a thorough visual inspection comprising of an in-depth check of the visual integrity of the plug, fuse, cable and case of the equipment under test.

Fixed Wired Appliances

The testing of fixed equipment or appliances is more difficult to inspect and test because of the nature of their attachment to the building fabric and their connection to the fixed wiring of an installation, usually via an isolator or fused connection unit (FCU). This doesn’t mean that only visual inspections are required for these types of equipment, they should still receive a full combined inspection and test at relevant intervals.

Functional Operation

he purpose of PAT Testing is to determine whether appliances are safe for use, it is not necessary for a member to check the correct operation of each appliance, unless the functional operation is dependent upon its safety.

Test Results

An association member is responsible for the production of a set of results to accompany the completed work and be sent to the customer after the work is completed.


Every appliance on passing the required standard to indicate that it is in a safe condition will have a non-destruct appliance label attached to a suitable part of the equipment stating the unique number, date of test and initials of testing engineer.


The association will offer to provide support to members in the even that a complaint is made against the member that has not been able to resolve the complaint initially.

A full version of the Working Standards is available for members to download from the members area