Maintaining an LV switchgear system is a critical part of ensuring the safety of your employees and your facility. A dirty or malfunctioning switchgear system can cause a fire or an electrical outage, which can damage equipment and can potentially lead to serious injury. This page will outline the steps necessary to clean your electrical switchgear system safely and effectively.
Fully Isolate Your Switchboard
Before you begin cleaning your electrical switchgear system, it is important to fully isolate the system from all sources of power. Check the mains, generation, UPS, PV, and CHP power sources. Once the system is completely isolated, you can proceed with cleaning the switchgear safely.
Clean Using Filtered Suction Equipment
When you are sure that the switchboard is fully isolated and completely safe, you can begin cleaning. It is important that you only use specialist cleaning agents because non-specialist products can cause short circuits and damage the switchgear system.
Use specially designed filtered suction equipment with a non-metallic hose to remove all dirt, dust, and debris from the system. Check the ventilation grills to ensure they are not blocked with dust and dirt. Always work slowly and be careful with suction equipment so you do not damage any of the equipment while you are cleaning. Avoid using compressed air to clean your switchgear because it can push contaminants further into the components and cause more damage.
Wipe Surface Dirt and Dust Deposits From The System
After using suction equipment to remove hidden dust, you should wipe surface dirt and dust deposits from the switchgear. Use microfibre cloths and lint-free cloths to pick up all of the dust and ensure that you don’t leave anything behind. Soft cloths also help you avoid damaging the switchgear during cleaning.
You can also use cleaning wipes that are designed for use with switchgears. They use fast evaporating solvents that are not corrosive to metal or plastics, so you can clean stubborn dust without causing damage to the components.
Wipe all surface dust and dirt from the insulation bushings, stand-off insulators, electrical leads, busbars and busbar supports, and all other general equipment.
Conduct The 10 Crucial Post-Cleaning Tests
After cleaning, there are ten crucial tests you must conduct to make sure that the switchgear is functioning properly and there are no parts that require maintenance. Once you have cleaned away all of the dust and debris, conduct these ten steps for a full switchgear service:
- Inspect electrical joints and connections for overheating – you can spot overheating joints and connections by looking for discoloration, deformation, or blistering
- Torque test a sample number of bolted connections – If the torque values are too low, the bolt could come loose due to vibrations.
- Check operation of mechanical & electrical interlocks – the interlocks on a switchgear are usually put in place for safety reasons, so it is vital to check that they are functioning as they should and staying locked in the right position.
- Check the switchgear system’s instrumentation – if the readings on the instrumentation are not accurate or certain instruments appear to not be working at all, repairs need to be made.
- Check for loose fastenings – all fastenings on the switchgear system must be tight to ensure that the system is stable and safe. You can check for loose fastenings by visually inspecting the system and by using a torque wrench.
- Check if the indication lamps are operational – indication lamps demonstrate the state of the circuit and the position and also alert you to any emergencies.
- Check that the insulated barriers & terminal shields are in place – these barriers and shields protect you from electrical shock, so it is essential that they are in the correct position and not damaged.
- Check for the presence of moisture – moisture can cause electrical faults, so it is important to check for signs of water ingress and deal with any issues as soon as possible. You can do this by checking for condensation or water droplets inside the switchgear. Using a dry cloth to wipe the area will also pick up any small water droplets. If you do find moisture, the components need to be thoroughly dried before the switchgear is in operation again.
- Check warning & operation labels are visible – these labels provide important information about the switchgear and what to do in an emergency, so it is essential that they are visible and not damaged. Failing to properly display them could cause somebody to damage the switchgear or injure themselves. It may also be in breach of health and safety regulations.
- Prepare and submit a report for each switchboard – this report should include all of the information from the tests that you have conducted, as well as any repairs or maintenance that needs to be carried out.
Performing these switchgear maintenance tasks on a regular basis will ensure that the system functions safely and efficiently. When you have finished cleaning and making all of the necessary checks, you can replace the covers. The switchboard then has pre-energisation tests and checks to go through but once these are complete, you can restore power and continue using the switchgear immediately.
Conduct Maintenance Of The Circuit Breaker (ACB and MCCB)
It is also important to conduct maintenance of the circuit breaker when cleaning your switchgear. Follow these key steps to do so:
- Record details and protection settings of each circuit breaker – this information should be kept in a logbook so that settings can be checked after maintenance to make sure they are correct.
- Inspect conductors for signs of overheating – look for discoloration, deformation, or blistering around the conductor.
- Check if the castell interlocks (door/cable) are operational – this is a key safety feature so it is vital that it functions properly.
- Manually open, close, and trip the circuit breakers to exercise their mechanisms – do this 20 times, at the very least, but preferably more to make sure that the circuit breakers are operating smoothly.
- Check the arc chutes for blockages – blockages can occur when the splitter plates erode. Look out for a layer of soot on the plates or small chunks of metal that are causing a blockage.
- Check the main contact wear – when conductive components become too worn, the circuit breaker ceases to function properly.
- Check if the chassis shutter is operational.
- Secondary inject electronic trip units to prove tripping curves – this needs to be done for long time, short time, instantaneous, and ground fault systems.
- Perform low ohm continuity tests across the live to load side of the circuit breaker – make sure to record the results.
- Perform the dielectric test across adjacent poles (and in between) on the circuit breaker – make sure to record the results.
- Prepare and submit a report for each circuit breaker – include all of the recorded information from dielectric tests and continuity tests. Make a note of any repairs that need to be carried out too.
Need Help With A Switchgear System?
At AF Switchgear, we are experts in installing and maintaining switchgear systems for a range of applications. Services we provide include:
- Switchboard modifications – installing MCCB, ACB, replace changeover controller, control circuit modifications (just to name a few)
- Fault finding & rectification
- Switchboard survey and investigations
- Emergency call outs
- Thermal imaging surveys
- PFC servicing
Contact us today and we can give you some expert advice and, if necessary, help you select and install a new switchgear system.
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