With countless products using electricity, electrical testing is an essential requirement for safety in every home and business. Today, many governments across the world employ various regulatory measures to ensure that safe operating standards are met by all products that use electricity. In the UK, all electrical materials, installations, machines and apparatus must be designed, manufactured and tested in compliance with the UK electrical industry British standards. For purposes of this discussion, this article will explain the role of electrical inspection and some examples of electrical tests. Learn more about the importance of Electrical testing from the Health And Safety Executive (HSE) Website.
Here are examples of electrical tests that must be done to electrical installations;
- Insulation resistance tests. This test involves measuring the total resistance of an electrical appliance by applying a voltage of about 500 volts to 1000 volts to the device. Here, each product must meet a minimum acceptable value of resistance of about one mega Ohm for it to pass the insulation test. In most cases, this test is carried out after every maintenance procedure to ensure the product is safe for use.
- High voltage tests. Here, the appliance to be tested is applied with a considerably higher voltage than the normal operating conditions to stress the device. This check tests the insulation of the product against high voltage, ensuring the product continues to function normally even when the voltage increases abnormally during operation. This high voltage test is a universal check which every unit must pass before it can be accepted for usage.
- Line leakage tests. The line leakage tests or leakage current tests are an important analysis for all medical devices. It measures the amount of undesirable current that leaks through insulation devices or dielectric of a capacitor. In most cases, a line leakage test is carried out at about 100% to 110% of the rated input voltage in the apparatus under test. The amount of current leakage should not exceed 210 microamperes. Today, this test is carried out in electrical products.
- Earth continuity tests. Here, the amount of ground resistance is determined by measuring the resistance between the third pin and outside the metal body of the appliance under assessment. The maximum amount of resistance allowed here is about 0.5 ohms although some standards may indicate 0.1ohms. During the test, the device may be subjected to relatively higher current, preferably between 25-60A to ensure the ground bond circuit keep up safe voltages on the chassis of the apparatus, even at elevated voltage, before its circuit breaker trips. Additionally, these earth continuity tests ensure that the product does not shock the user due to insulation failure.
Electrical tests: why are they important?
In general, electrical testing is mandatory for safety reasons. Since this inspection is obligatory, it is always advisable for users to ensure electrical installations in their homes and businesses are regularly tested by skilled electricians to identify and fix any problem that may hinder the safe use of the devices. More so, premises that are open to the public such as cinemas, schools, commercial rental houses, pubs, churches, hospitals and dental surgeries should be inspected yearly while private premises should be tested at least after every ten years. An electrical inspection should never be ignored and should be done licensed personnel. In the UK, electrical inspections should be completed according to the UK requirements for the safety of electrical installations, IEE writing solutions.