IEEE recommended Electrical Installation Tests
After completing electrical installation work by a licensed contractor, as required by Kenyan law (THE ELECTRIC POWER ACT, 1997 (No 11 of 1997), Electrical installation tests must be performed on the Electrical Installation guided by IEEE (Institute of Electrical and Electronics Engineers) regulations and / IEC 60364 Electrical Installations for Buildings.
Why is it Important to conduct IEEE recommended tests on electrical installations?
IEEE recommended tests on a completed electrical installation must be performed on any installation before commissioning to prevent damage to property or even loss of life due to a fault in the installation. The sole purpose of IEEE recommended tests on a completed electrical installation is to ensure that people and property are safe and protected in the event an electrical fault occurs. It also facilitates maintenance on the installation, preventing serious faults whose consequences are undesirable due to the high cost associated with such. Production shutdown may also result and directly affect revenues for an organization.
What are the IEEE recommended tests on a completed electrical installation that should be performed?
There are a number of tests recommended that should always be performed on new Electrical installations, Modified electrical installations, and periodically on existing installations. They include the following;
- Earth Resistance Test
- Earth Continuity Test
- Insulation Resistance Test
- Test for Polarity
- Tests of protective devices
#1 Earth Resistance Test
In order to ensure safety on an Industrial, Commercial or domestic installation, an Earth Electrode must be installed. If this is not done, there exists a high risk to life and damage to property.
Earth Resistance can be measured with the help of Megger earth tester or Earth megger.
When a sufficiently large enough area is available to set up stakes, the traditional 3-pole method can be used. The method is also known as the 62 % method. In Instances where the 62 % method is not applicable, other methods can be used.
Different methods for measuring the earth resistance are available with some more suitable than others. Prevailing circumstances determine the method type to be used. Factors to be considered when selecting the method include the following;
- The neutral system used
- Installation type (residential, industrial, urban, rural, etc.)
- The possibility of isolating the power
- The area available for planting stakes, etc.
#2 Earth Continuity Test
The purpose of Earth continuity measurement is to check the bonding of the protective conductors and the main and supplementary equipotential bonds. There must be a low impedance path from equipment to earth(soil). As defined by IEC standards, the test is conducted using a ground tester instrument, capable of generating a no-load voltage of 4 to 24 Volts (DC or AC) with a minimum current of 200 mA. The resistance measured must be lower than a threshold specified by the standard applicable to the installation tested, which is usually 2 Ω. As the resistance value is low, the resistance of the measurement leads must be compensated, particularly if very long leads are used.
#3 Insulation Resistance Test
Sound insulation is highly essential in preventing electric shocks. The insulation resistance is measured across the earth and the whole system of electrical conductors. This test ensures that the integrity of cable insulation or wires is not compromised and there is no leakage between them. When conducting this test, all fuses should be in place and all switches closed, and except in concentric wiring all lamps in the position of both poles of the installation otherwise electrically connected together.
According to the IEC 60364 standard, the minimum insulation resistance values must be as follows:
#4 Test for Polarity
This test is essential in low voltage installations. The sole purpose is to ensure that all single pole switches are connected to phase wire throughout the installation.
It is critical to wire all switches on phase or live phase to ensure that when a switch is in the OFF position, the connected appliance is truly dead. If the switch is connected to the neutral wire, it is important to note that the connected appliance will be connected to the phase even if the switch is in the OFF position. Such is undesirable as it compromises the sole purpose of the switch. Connecting the switch to the neutral will not affect the operation of the connected appliance but compromise safety.
One simple method of carrying out a polarity test is by using a test lamp. Before conducting the test, the main switch should be in the ON position, all switches in the OFF position, and all other appliances removed.
One end of the test lamp is directly connected to the earth point and the other end to the incoming terminal of the switch
#5 Tests of protective devices
- Fuses and Circuit-breakers
To check the specifications of the protective devices such as fuses or circuit breakers, a fault loop impedance measurement is carried out to calculate the corresponding short-circuit current. A visual inspection can then be used to check that the sizing is correct.
- Residual current devices (RCDs) RCDs, which detect earth leakage currents, can be tested using two methods: – the basic test, also called a pulse test, which determines the trip time (in milliseconds) – the step test, which determines the trip time and trip current, thus detecting any RCD aging.
PID Systems Engineering on IEEE recommended Electrical Installation Tests in Kenya and East Africa
PID Systems Engineering Ltd is one of the leading Electrical Installation service providers in Kenya. We also conduct Installation testing services for new, modified, or existing installation services in Kenya and East Africa. If you are looking for quality Installation services, search no further.
We assess your exact status of the Installation, based on data collected during test and engineering principles with adherence to IEEE regulations. Afterward, we advise our clients on sustainable recommendations aimed at increasing the facility’s safety in a cost-effective way.
We use various methods testing methods that are guided by the type of installation. Our highly trained and experienced team will take measurements through our state of art instruments, collect relevant data, perform calculations and make recommendations on what to do to improve your facility’s safety.