In facility management, preventive maintenance is the main aspect supervisors or managers need to pay attention to because it is what determines how long the facility, equipment or tool will stay before it gets damaged.
Recently, I engaged in an inspection with my team in my field as an electrical engineer and advice a particular test to be carried out on all appliance and this is the main focus of this article.

_{Pixabay: Probe For Measurement by uplo}

Are of aware of PAT Test?

In my country, some company did not follow safety policy on their employee talk more on their pieces of equipment and this has affected the life span of so many equipments that would have spent more years before they pack up. In my practice, it occurs to me that maintenance and safety has a major role to play in any organization.
Now, let's talk about PAT testing.
What is PAT?

This is an acronym from three words which are Portable, Appliance and Testing. It is one of the tests common to all portable electrical appliance in a company, industry, home, and business centers. How many of us can be bold to say my appliance is PAT testing up to date? In some countries like Britain and Ireland has policies that enforce PAT testing on every electronic device they have regularly.
PAT testing is common to electronic devices like TV, electric fans, Video Player, and others. In PAT testing, the technician or trained personnel on electronics carried out in-service inspection and testing of electrical equipment during this testing and I will pick up one of the tests we carried out. Before I show you one of the tests, we need to understand that the main reason for carried out PAT testing on an electrical appliance is to examine them if they are safe to use. Every PAT testing carried out is to the advantage of the user and the equipment itself.

Electricity is a good servant but a bad master. _{Engr. Peter Ewesor, MD/CEO NEMSA & Chief Electrical Inspector of the Federation}

The electric current serves you because it is under your control, and the moment you are unable to control it, it becomes dangerous. There is a type of tests you can carry out on electrical appliance to maintain the safety of that equipment when in use.

Types Of PAT Testing On Electrical Appliance

Every type of test carried out on electrical appliance is a determinant of what type of appliance are you testing. In addition, PAT testing is a professional act exercise on electrical equipment that during a physical inspection, technician or electrician unable to determine the fault on such an appliance.

Test 1: Most of all electrical appliances come with a plug, it is a must to check the plug and watch out for naked wire and burnt out fuse.
Test 2: Earthing Resistance testing: When considering this type of test, you consider for the connecting rod and earthing rod. The resistance of these two rods must be the same and it's usually fewer than 5ohms when you have a value equal to 5ohms or greater then the device is not good for use.
Test 3: Earthing Continuity Test: This type of test is carried out on any earthing protection conductor with less than 1ohm.
Test 4: Polarity Test: On equipment, it is important to carry out checks on the live and neutral connection of a plug end whether both are correctly connected to the socket in a corresponding manner.

Example of PAT carried out In One Of Facility I Manage

All pieces of equipment are in the team custody to maintained and it was a period for the team to carry out the check on Clarke Fan of over 50 numbers.

The Clarke Fan most we call them Drum Fan due to the shape of the fan and it is usually a powerful industrial fan with very big diameter impellor (766mm). This type of fan is used in the industrial, commercial, agricultural and automotive premise as ideal ventilation to keep a stuffy area or atmosphere fresh and also to vent nasty odors. This particular fan is ideal in warehouses to guide against heat that can be build up as a result of poorly ventilated areas.

When carried out this test, it is of almost important to connect the equipment to the appropriate test socket.
After the test carried out, 16 fans failed PAT.
Point To Take Note:
When your PAT device display above 1.99Ω your test is overrange and this is a fail for earth bond test.
When your PAT device display above 19.9MΩ and this is a pass for an insulation test any other value below 19.9MΩ is a fail. If you have overrange result when testing a fuse it simply tells you that the appliance draws more than a few mA which is a pass.

_{Picture Taking During PAT Test On Drum Fan}

The resistance test that was carried out suppose to have the value of less than 0.1ohm but during the test, we recorded value bigger which means the fan has failed and we need to find out the problem. After the check, it was traced down to VDR connected by the regulator terminal. VDR is termed Voltage Dependent Resistor or Varistor and its function is to vary the applied voltage that passes through the terminal before it gets to the equipment. Its act a protective component for the fan in case of an electrical surge. You can read more about it Here

In conclusion, PAT testing is good to be carried out regularly not because is a policy but because it's to safeguard you and the equipment from danger. When you think of safety first in your dealings you will take every safety policy important.

You can watch the video I slighted on youtube some few hours ago during my study, though the video is 8 years old but is still very relevant to PAT testing practically.

References

1. Martindale Easypat Manual EASYPAT 1600
2. MachineMart.co.uk Clarke CAM600 30" Drum Electric Fan
3. Wikipedia.org Varistor by Free Encyclopedia