Low and medium voltage switchboards play an important role in the safety and efficiency of an electrical distribution system. Many industrial, commercial, and residential buildings rely on switchboards to effectively distribute electrical power to appliances or electrical devices that are then used by consumers. Without proper construction and maintenance of the switchboard, failures in the switchboard gear may occur, and prove to be costly and dangerous.
In order to facilitate the safe distribution of electrical power, switchboards must be built according to specific standards. Basic requirements for switchboards are described in Article 408 of the National Electric Code, and are also built according to standards set by both the Underwriters Laboratory (UL 891) and the National Electrical Manufacturers Association (NEMA PB2). It is essential that all electrical switchboard components are designed, constructed, and installed correctly in order for safe operation of the switchboard.
Benefits of a Maintained Switchboard
Electrical distribution equipment is not immune to aging, and it will slowly deteriorate over time. Factors such as the environment or the conditions in which it is operated can speed up this process. In order to continue to effectively distribute power, the switchboard will require routine maintenance. While this may seem like a chore, there are numerous benefits to keeping your switchboard in good shape:
One of the most important reasons why a switchboard should be well maintained is that it keeps everyone safe. No matter how often you operate a switchboard, it will continue to age, and it needs to be routinely inspected and tested. Without routine inspection and testing, switchboards can experience equipment failures that put others at risk of electrocution, fires, and even explosions.
Increased Lifespan of the Switchboard
Regular maintenance of the switchboard will increase its lifespan, which means fewer replacements in the future. This can save plant facilities money with their electrical distribution system and help them get the most out of their equipment.
Reduced Amount of Unexpected Equipment Failures
Unexpected outages can be slight annoyances in some cases and costly in others. Sticking to a regular maintenance schedule will ensure that the switchboard is working properly and will reduce the chance of equipment failure.
How to Maintain a Switchboard
For optimum performance and safety, switchboards should be subjected to preventative maintenance, testing, and inspections.
If you have purchased a new switchboard, it is recommended that you immediately inspect it for any signs of damage that could have occurred during shipment. For existing switchboards and switchgear, preventative maintenance procedures should be established. This could include the following procedures:
- Checking the tightness of fastenings on the switchboard.
- Internal cleaning to clear out the accumulation of dust or dirt.
- Checking the condition of insulation and replacing any conductors that show damage.
- Inspecting the operation of the circuit breakers.
- Testing the gaskets on doors and the condition of weather seals.
- Keeping the assembly dry.
- Making sure that all bolted panels are secure.
- Inspecting control wiring and replacing wires as needed.
Regular testing should be performed to ensure that the switchboard is functioning as it should. These tests could include either high potential testing or insulation resistance testing.
Insulation resistance tests: To measure the insulation resistance, a megohmmeter is used. Deterioration of insulation must be corrected immediately.
High potential capability tests: These tests are not required, but may be needed after repairs or modifications have been performed to verify insulation. It ensures that no current flows are isolated and not flowing between certain points. This helps guarantee the safety of the switchboard.
Continuity test: The opposite of a high potential test, this test checks that current flows easily from one point to another.
Other Maintenance Tips
In addition to preventative maintenance and testing, there are some other maintenance tips that operators should note:
- Keep records of past inspections and a detailed schedule of installed switchboards.
- Purchase spare switchboard parts to keep on hand for vital operations.
- Have a well-stocked shop with testing instruments and storage of spare parts for safety and efficiency.
- Only those authorized to operate the switchboard should perform regular maintenance and inspections.
Like most operational equipment, switchboards are subject to wear and tear. The conditions that the switchboard operates in will play a role in how often maintenance should be carried out. However, it is generally recommended that switchboards be inspected every three to six months and include annual testing. Through proper maintenance of the electrical switchboard, plant facilities can expect to save money by reducing the likelihood of equipment failure and make operating the switchboard safer.