Appliances-Equipment Electrical Repair Safe Work Method Statement

With power isolated, conduct all resistance measurements including motor winding resistance to identify open or shorted windings, continuity testing through wiring and components, insulation resistance testing applying test voltage between windings and earth, capacitor condition testing using capacitance meter, contact resistance measurements on switches and contactors, and earth continuity verification. These tests provide comprehensive diagnostic information without electrical contact hazards. Only restore power for specific tests that require energised circuits including supply voltage measurements, control signal verification, component operation under load, current draw measurements using clamp meters, and functional testing to verify repairs. By maximising isolated testing, you minimise exposure to electrical hazards. Many faults can be completely diagnosed with power isolated eliminating need for live testing. For faults requiring live measurements, don arc flash PPE, work with second person present, test with one hand where possible, and de-energise immediately after obtaining necessary measurements. Never conduct live testing alone or without appropriate PPE and controls.

Use purpose-built capacitor discharge tools consisting of resistor bank in insulated housing with appropriate voltage and power rating. Never use screwdrivers or wire jumpers creating direct short circuits which can cause violent discharge, weld components, and create arc flash. The proper procedure is: first verify electrical power isolation is complete, don insulated electrical gloves rated for voltage level, maintain safe distance from capacitors during discharge, connect discharge tool across capacitor terminals and hold for minimum 30 seconds allowing resistive discharge, remove discharge tool and immediately measure voltage across capacitor terminals using voltage tester to verify zero voltage. If voltage is still present, repeat discharge procedure and investigate for external charging sources. After confirming discharge, install temporary short circuit across capacitor terminals using insulated wire maintaining discharged state during repair work. Large capacitor banks require discharging each section individually. High-voltage capacitors in equipment above 1000V require special long insulated discharge sticks operated from safe distance. Document capacitor discharge in work log. Never assume capacitors are discharged based on time since isolation - always verify with voltage measurements.

Comprehensive energy isolation requires systematic approach addressing all energy sources. First, identify every energy source including electrical power, stored electrical energy in capacitors, mechanical energy in rotating equipment or coupled machinery, pneumatic and hydraulic pressure systems, potential energy in elevated loads or compressed springs, and thermal energy in heated components. Second, plan isolation sequence usually isolating electrical power first, then mechanical isolation, then pressure systems, then stored energy discharge. Third, isolate each energy source using appropriate lock-out device - circuit breakers get lock-out hasps, isolator switches get lock-out covers, valve handles get lock-out devices. Fourth, each worker applies their own personal padlock that only they control keys for - if three workers are involved, three separate padlocks are applied. Fifth, attach danger tags to each isolation point describing worker name, date, and work being performed. Sixth, verify zero energy state through testing at work location - use voltage testers for electrical, attempt to operate controls for mechanical, release residual pressure carefully for pneumatic/hydraulic. Only after verified zero energy on all sources, commence repair work. Maintain isolation throughout repair until all tasks complete and all workers are clear. Each worker removes their own lock only - coordination meeting required before removing group isolation.

Arc flash PPE is required whenever working within calculated flash protection boundary on energised equipment or circuits. For most 415V three-phase motor control and distribution equipment repairs, flash protection boundary extends 1 to 2 metres from arc source. If work requires approaching within this boundary while circuits are energised including live testing with multimeter, verifying operation after repairs, or energising equipment under test, arc-rated PPE is mandatory. Minimum protection level for 415V three-phase repairs is 8 cal/cm² arc rating including arc-rated long-sleeve shirt and trousers, arc-rated face shield over safety glasses, and insulated electrical gloves with leather protectors. Higher fault current locations or higher voltage equipment requires higher arc ratings determined by arc flash calculation or equipment labelling. Arc-rated clothing must cover all exposed skin - no gaps between shirt and trousers. Position body to side of equipment rather than directly facing potential arc source. Higher-risk repairs on main distribution equipment, switchboards with high available fault current, or high-voltage equipment may require arc ratings exceeding 25 cal/cm², layered arc-rated clothing, or switching to remote testing methods operated from outside flash boundary. Arc flash risk is highest during initial energisation after repairs when equipment condition is not yet verified - maintain maximum possible working distance during initial power application.

Motor insulation resistance testing using insulation resistance tester provides critical indication of winding condition. Apply test voltage appropriate for motor operating voltage - 500V test voltage for motors up to 500V operating voltage, 1000V test voltage for motors 500-1000V. Measure resistance between motor windings and earth, and between phases. Minimum acceptable insulation resistance is 1 megohm regardless of motor size or voltage - readings below 1 megohm indicate insulation breakdown requiring investigation. Newly manufactured motors typically show insulation resistance exceeding 100 megohms. Motors in service typically show 10-100 megohms depending on age, contamination, and operating environment. Readings below 10 megohms but above 1 megohm indicate declining insulation condition requiring monitoring. Readings approaching 1 megohm indicate imminent failure requiring motor removal from service. For motors that have become wet or contaminated, drying in warm oven can restore insulation resistance. If drying does not restore readings above 10 megohms, rewinding is required. Compare insulation resistance between three phases - significantly lower reading on one phase indicates localised insulation damage in that winding. Temperature affects readings - correct to standard temperature if testing hot motors. Document baseline insulation resistance values when motors are new or newly rewound providing comparison for future testing. Trending insulation resistance over time identifies gradually deteriorating motors allowing planned replacement before catastrophic failure.

Electrical repairs in operating industrial facilities present additional hazards beyond the repair work itself. First, establish clear communications with facility operators before commencing isolation - coordinate isolation timing, duration, and verification procedures. Second, verify isolation device you are working on controls only intended equipment - in complex facilities with multiple equipment, incorrect isolation identification is common cause of electrical contact incidents. Test at work location rather than assuming isolation device position indicates safe state. Third, establish physical barriers and signage around repair work area preventing entry of facility personnel unfamiliar with electrical work in progress. Fourth, coordinate with other trades including mechanical maintenance, cleaning staff, and production workers who may need access to area. Fifth, be aware of mobile plant including forklifts, pallet jacks, and utility vehicles operating near repair work area - establish exclusion zones preventing vehicle contact with repair work area or test equipment. Sixth, if repair work requires floor space, coordinate with facility operations to redirect traffic or material handling. Seventh, for repairs on production equipment, obtain clear authorisation from production supervisors before commencing isolation affecting production schedules. Eighth, maintain clear communication throughout repair work using two-way radios or mobile phones ensuring rapid contact if coordination issues arise. Ninth, when re-energising equipment after repairs, verify facility operators are aware and prepared for equipment restoration. Working in operating facilities requires continuous situational awareness beyond technical repair skills - electrical workers must coordinate with facility systems and personnel for safe work completion.