8 September 2020 - 1:38pm

The 5th Edition of the Code of Prcatice for the In-service inspection and testing of electrical equipment is soon to be here

The 5th Edition of the Code of Practice for In-service Inspection and Testing of Electrical Equipment is almost upon us and based on the draft and official commentary here are the salient points of the new document.

There is a push to lose the moniker ‘PAT testing’ to embody the fact the code is for all electrical equipment including fixed equipment. The code addresses the changing nature of electrical equipment that is now commonplace, including modifications to the way that it is tested.

It builds on the previous edition and the HSE’s focus on achieving the appropriate amount of testing (not over or under testing). The emphasis is on the verification of electrical equipment for continued use.


There is more emphasis on inspection, both user checks and formal inspections. For example, an appliance could electrically test satisfactorily but there could be an unsecured cover that if it fell off would expose live parts. So, the importance of visual inspection is stated. In certain cases Class II equipment only needs a regime of inspection, no electrical testing.

There is an educational wall chart to help inform the obligation of users.

Electrical Testing

Clear reasoning and explanation about electrical testing is given to enable a rational view on the testing required.

1. Earth continuity testing

 Guidance on the use of the options of currents available for this test with the recognition that a low current (100 mA to 200 mA) is the ‘normal’ way to proceed.

Issues with testing results are discussed and an opening up of the pass limit for older equipment to 0.5 Ω.

2. Insulation Testing

Clarity in the use of the test voltage 500 V for insulation testing. The first choice is to conduct a test at 500V if this cannot be done then 250 V followed by a run leakage test is likely to be the advice, when the final code comes out.

Explanation about the anomalies that can appear when testing switch mode power supplies and equipment with SPDs and testing these at 250V


There is recognition of different levels of skill required for testing from someone capable of using a go / no-go tester to someone capable of safe isolation and testing fixed appliances.

Risk Assessment

Gone is the table of test frequencies verses class of equipment, type of equipment and environments. This is because, in reality, there are too many variables that should be considered which cannot be replicated in a simple table. It is replaced by examples to give guidance on the procedure and thought process needed to come up with a reasoned regime of inspection and testing.

Class of Equipment

CLII FE class of equipment is recognised. This is Class II equipment that requires a functional earth (for the purpose of a voltage reference or to clear potential static build up, for example).


All in all, this new document makes a good job at drawing on the history of past codes and current field practice and makes it applicable to electrical equipment in use in these modern times and the test equipment available for testing.

Kewtech's range of PAT testers are all 5th edition compliant and all have the much talked about 250V and 500V insulation options. The top of the range Smartpat which is driven by the KEWPAT app even makes it compulsory to run an insulation test before a run leakage test which is a prerequisite in the new code.