I had an estate agent visiting my house recently to give me evaluation. She gave me some forms to fill if I decide to rent through them. According to the form, it is required to have a gas safety certificate before the tenancy starts and it has to be done every year. For the electricals a PAT is required, PIR is not required but recomended (every 5 years). It is for a family type dwelling, not HMO.
It is interesting what you say. I would guess the term PAT is loosely used as to be considered as portable items need to be under a certain weight or have wheels designed to allow them to move on a regular basis. So a vacuum cleaner even a Kirby will be considered portable but washing machine, fridge, freezer, cooker, dishwasher, immersion heater etc are not considered as portable although they do of course need testing.
The problem arises that many of these items need some dismantling to test as some bits are controlled by timers so using a simple PAT tester would not highlight many of the potential faults. The only way is sometimes a maintenance contract and these show that the item is being checked at regular intervals even if in practice the guy only comes out when it breaks down.
Unfortunately it is all too common for the guy doing PAT testing to only test items which can be plugged in and easily tested and since it is not required to mark items as tested it is only listed in paperwork then all too often items are missed.
The correct term is "Inspection and testing of in service electrical equipment" and that covers immersion heaters etc. We had some heated arguments at work at what should be tested by each system and I would point out that although a fridge (Not frost free type) is not a portable appliance that with some thought it could be tested far easier with a PAT tester then with a 16th Edition test set and all it needed was for the tester to unplug it as he entered the room then test everything else and leave the fridge to last and 9 times out of 10 it will have warmed up enough to to run when tested. However of course with frost free units then it would require some dismantling to gain assess to the defrost heaters and these units should be on contract maintenance. The washing machine and dish washer with motors, pumps, and heaters can't be PAT tested and will need a maintenance contract. Yet the immersion heater in spite of being fixed to the fabric of the building can be easily PAT tested. At one time 15A plugs were used for immersion heaters making it very easy.
What one has to consider is if PAT testing is merely to satisfy a letting agents whim or if you really want to ensure all equipment is safe? There are so many items that in practice don't need testing. If the connect size fuse and RCD protection is used then any fault with an immersion heater will open a protective device. This is of course the same for most other items. So really all that needs testing is that the earth is connected and although keeping the records and look for a trend may be what we should do if one was to do a risk assessment in most cases it would seem OTT.
However to include a method statement and risk assessment it the paperwork given to a letting agent would likely really confuse them. Hence why so many tests are really just a rubber stamp. Even testing a kettle how many look inside and reject the kettle if the plating on the element has started to flake off so that metals are being put into the water? OK it's not electrical but putting a safe sticker on the side of equipment which is not safe is not really the way to go! The same applies to build up of dust in tumble driers, it may not present an electrical problem but it is a fire risk.
Do remember it is the responsibility of the user to visible check electrical equipment before using! We as electricians should never find a frayed lead on a PAT test as well before that point the user should have reported it and had it corrected.