PREVENTATIVE MAINTENANCE
ELECTRICAL DISTRIBUTION SYSTEMS
SAFETY PRACTICE
Prepared By – Sharif A. Ch.
ELECTRICAL SAFETY TIPS FOR THE WORKPLACE
❒ Prevent all potential contact with live electrical current.
❒ De-energize equipment and use lockout/tag out.
❒ Ensure safe use of electrical equipment.
❒ Install proper physical barriers around electrical hazards.
❒ Beware of conductive tools and cleaning materials.
❒ Only qualified personnel should work on live electrical wires
❒ Always follow your company’s electrical safety work practices
INTRUSIVE LV SWITCHBOARDS
❒ Check function of all power meters before shutdown.
❒ Check function of lamps and indicators.
❒ Inspect locking devices for signs damage or worn.
❒ Clean thoroughly, vacuum and full visual inspection of exterior and interior of
all LV switchboards.
❒ Inspect control wiring, relays, power supply units, timers, etc. where
applicable.
❒ Check electronic surge protection is intact where installed.
❒ Verify control circuit fuses rating and continuity.
❒ Check and torque test bolted electrical connections as necessary to specified
levels.
❒ ACB maintenance withdrawal or fixed, check contacts, arc chutes secondary
injection, etc.
❒ Visual inspection for signs of overheating or deterioration.
❒ Final visual inspection to insure all clear after work completed.
❒ Inspection of all panels for paint work damage and signs of corrosion.
❒ Check battery tripping packs, battery integrity, signs of defects, etc.
NON-INTRUSIVE LV SWITCHBOARDS
Note: These maintenance procedures require no shutdowns.
❒ Check function of all power meters before shutdown.
❒ Check function of lamps and indicators.
❒ Inspect locking devices for signs damage or worn.
❒ Clean thoroughly, vacuum and full visual inspection of exterior only.
❒ Visual inspections of control wiring, relays, power supply units, timers and
fuse carriers.
❒ Check electronic surge protection is intact where installed.
❒ Visual inspection for signs of overheating or deterioration.
❒ Inspection of all panels for paint work damage and signs of corrosion.
❒ Check battery tripping, battery integrity, signs of defects.
ACB CHASSIS
❒ Rack out ACB.
❒ Clean/ vacuum internal chassis.
❒ Check operation of safety shutters closing.
❒ Check shutter locking devices are intact.
❒ Check operation and position of contacts.
❒ Operate padlocking system.
❒ Grease clusters as necessary.
ACB’s
❒ Check general condition of the device.
❒ Clean with diluents Henkel 273471, vacuum ACB.
❒ Check filters clean/vacuum arc-chutes.
❒ Visual check for contact wear.
❒ Check auxiliary wiring insulation.
❒ Check ACB locking devices.
❒ Open/close manually.
❒ Charge the device manually.
❒ Secondary injection with FFT Kit, produce trip curve report.
❒ Check earth fault protection/earth leakage protection.
❒ Grease disconnect contacts as necessary.
❒ MCCB trip test with report.
BUSBAR & ACCESSORIES
❒ Visual inspection all Power bar runs
❒ Check supports
❒ Check alignment, straight runs, joint packs and directional change pieces
❒ Check panel flanges, earth continuity etc.
❒ Thermal image survey of complete runs
METERS
❒ Voltage connections
❒ CT connections
❒ Modbus connections
MCCB CHECKS
❒ Motor operator
❒ Under voltage release
❒ Power supply unit
❒ Control relays
❒ Fuse and fuse holders
PDU
❒ Clean thoroughly exterior and interior PDU switchboards
❒ Check function of all power meters
❒ Verify control circuit fuse rating and continuity
❒ Check function of lamps and indicators
❒ Check and torque test bolted electrical connections as necessary to specified levels
❒ Check all cable connections for tightness and torque terminals
❒ Visual inspection for signs of overheating or deterioration
❒ Inspection of all panels for paint work damage and signs of corrosion
❒ Inspection to insure all clear after work completed before fitting covers
❒ All labeled secure in place
THERMAL IMAGING SURVEYS
Thermal imaging is becoming more common within preventive maintenance programs to
help detect excess heat in electrical components. It can be carried out while the system is
under a full load with no impact to operations
Thermal imaging technology can detect loose connections, corroded elements, short
circuits, overloaded circuits and busway-joint analysis. This non-invasive technique also
allows to gather data from a remote location, away from potentially dangerous situations.
With electrical distribution systems continuing to top the list with the most premature
breakdown, an electrical preventive maintenance program will effectively reduce your risk
of an unscheduled outage by as much as 66%.
It is important to remember that performing electrical maintenance does require specialized
training in testing technology and safety. Energized testing is a key component, staff will be
working on live equipment, therefore safety MUST always be a primary concern.
END OF REPORT
