Our PAT Testing Procedure

All testing is carried out under the IEE's (Institute of Electrical Engineers) Code of Practice for In-Service Inspection and Testing of Electrical Equipment and conforms to HSE (Health & Safety Executive) guidelines.

Before any testing commences on an appliance, we will assess the close environment to make sure testing can be carried out safely and with no risk to either themselves or people working in the environment.

Inspection and Testing is carried out in several stages and here is a breakdown detailing the various tests which may be carried out on electrical appliances during inspection & testing:

Visual Portable Appliance Inspection

Visual inspections should be carried out by a competent member of staff who knows what to look at, what to look for and how to avoid danger to themselves and others. This type of inspection does not require the use of any specialist test equipment as it is purely a visual inspection. The inspection should include, when disconnected from the mains supply, the removal of the plug cover and checking that:

• damage, such as cuts or abrasions to the cable covering;
• damage to the plug such as the casing is cracked or the pins are bent;
• non-proprietary joints, including taped, in the cable;
• equipment that has been used in conditions where it is not suitable, such as a wet or dusty workplace;
• damage to the outer cover of the equipment or obvious loose parts or screws;
• overheating (burn marks)
• The cord grip is holding the outer part of the cable tightly
• The wires, including the earth wire where fitted, are attached to the correct terminals
• No bare wire is visible other than at the terminals
• The terminal screws are tight
• There is no sign of internal damage, overheating, dust or dirt
• Cables located so as to avoid damage (i.e. run unprotected under carpets)
• Means of disconnection/isolation readily accessible
• Adequate equipment ventilation
• Cups, plants and work material correctly placed to avoid spillage
• Equipment positioned to avoid strain on cord
• Equipment is being operated with the covers in place and any doors are closed
• Indiscriminate use of multi-way adaptors and trailing sockets is avoided
• Correct size fuse fitted, BS marked, ASTA marked

This visual inspection will not include taking the equipment itself apart.

Combined Portable Appliance Inspections and Tests

The checks carried out as above will have identified most (but not all) potentially dangerous faults - some deterioration of the cable, its terminals and the equipment itself can be expected after significant use. Equipment may also be misused or abused to the extent that it may give rise to danger. Testing, together with a thorough visual inspection can detect faults such as loss of earth integrity like a broken earth wire within a flexible cable, or deterioration of insulation integrity or contamination of internal or external surfaces.

Examples of some of the tests that we will carry out, as deemed necessary, are as follows:

Earth Bond Testing

• The safety of certain appliances depends upon a connection with the earth for its safety.
• A test is carried out using electrical test equipment to ensure a safe earth is present in the appliance.
• The test is to ensure that the connection between the earth pin in the mains plug of the appliance and the metal casing of the appliance is satisfactory and of sufficiently low resistance.
• (Class 1 equipment only): Readings should show less than 0.1Ω (Ohms) –R1 (where R is the resistance of the lead) Tested at a current of 1.5 times the rating of the fuse and no greater than 25A for a period of between 5 and 20 seconds or with a short-circuit test current within the range 20mA to 200mA.

Insulation Testing

• A test is carried out using electrical test equipment to ensure the insulation resistance in the appliance is at a safe level.
• This test is used to verify that adequate insulation exists between the mains supply pins and the earth.
• The applied test voltage should be approximately 500 Vdc Class 1 heating equipment < 3kW 0.3M Ohms Class 1 All other equipment 1M Ohms Class 2 Equipment 2M Ohms Class 3 Equipment 250k Ohms.

Substitute Leakage Test

• The sub Leakage Test applies a nominal voltage of 40V AC RMS to the appliance and is applied between the earth pin and both the live and neutral pins of the supply plug.
• This test can prove useful in situations where neither conventional insulation nor flash tests are acceptable methods of testing the insulation of the appliance.

Flash Testing

• This test is rarely carried out and only then on certain appliances such as power tools.
• A test is carried out to measure the insulation of an appliance if a very high test voltage is applied to it.
• This test is used to determine that the insulation is of sufficient strength to prevent breakdown, particularly where high transient voltages are likely.

Earth Leakage Measurement

• A test is carried out to monitor the current flow through the earth lead of the appliance.
• The leakage test shows the current being lost through leakage as the difference in the currents flowing in the live and neutral conductors. This difference is the total leakage away from the appliance.
• This test is of particular value when an appliance incorporates a number of sequences, which may change the electrical characteristics of the appliance during its operation.

Load Test

• A test is carried out applying a voltage through a current limiting resistor to the mains supply plug and checks that the current flow will not be excessive when full voltage is applied to the appliance. The current flow is also compared with the declared current rating stated on the appliance’s information plate.

Touch Leakage Test

• The touch test displays the current that would flow if a person touched the appliance.
• The electrical test equipment detects any current flowing in the earth bond lead and indicates the potential leakage through a metal panel. The maximum values permissible are as follows:

  Class 1 Handheld Appliances 0.75mA
  Other Class 1 Appliances 3.5mA
  Class 2 Appliances 0.25mA

Functional Check

• A test is carried out to ensure that the appliance is working correctly and basically does what it is supposed to do in the right environment.
  For further information, please contact us on 07514 965222 , 01246 220523 or email us directly on enquiries@spirePAT.co.uk
  

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