Having seen both sides of the debate, I would argue there are cases when doing the ‘PAT Testing’ in-house is beneficial and on the other hand I know in some cases it would be better to use a contractor.
If I had a business with a small amount of electrical equipment, I would get one of my staff trained, buy some suitable test equipment and do the testing in-house. This way I can control the frequency of inspection and testing and also the cost.
Conversely, if I had many thousands of items (I have been to many sites with over 100,000 appliances), I would argue that bringing in a contractor would be a better idea. Doing it in-house would require a team of inspectors, a number of test devices and a large amount of uninterrupted time to complete the job to the required standard. In this case, the resources required would be beyond most organisations.
Whether you are doing the ‘PAT Testing’ in-house or not, it is always advisable to have someone on the team who has a working knowledge of ‘PAT Testing’. The role is often seen as a ‘license to print money’ and I have witnessed a number of contractors simply labelling items and fabricating test results for the report. If I was using a contractor, I would have a trained member of staff ‘shadowing’ them and keeping a close eye on what they are doing.