Safety, Environmental, and Energy Management
This domain covers safe work practices, environmental obligations, and energy performance. Expect questions on arc flash, isolation, waste handling, and power-factor or harmonic management.
Core rules
- Lockout/tagout: isolate, lock, tag, prove dead with a tested instrument, and earth or discharge before work.
- Arc flash assessment gives incident energy and the arc flash boundary; PPE is chosen from incident energy, not voltage alone. Approach boundaries are separate from the arc flash boundary.
- Environmental controls cover SF6 (a potent greenhouse gas, recovered not vented), insulating oil (PCB and spill rules), and lead-acid battery recycling.
- Energy management follows a hierarchy: eliminate, reduce, recover, then improve efficiency; ISO 50001 uses a plan-do-check-act cycle with an energy baseline.
- Capacitor correction reduces reactive current and losses but does not reduce the kW consumed.
Worked example
A plant draws 500 kW at 0.75 power factor. Present reactive power = 500 × tan(41.4°) = 441 kvar. Target 0.95: kvar = 500 × tan(18.2°) = 164 kvar. Required correction = 441 − 164 = 277 kvar. After correction, apparent power falls from 667 kVA to 526 kVA, releasing transformer capacity and cutting line losses, while the 500 kW real demand is unchanged.
Traps
Choosing PPE by nominal voltage, ignoring that capacitors can resonate with harmonics and amplify distortion, and treating power-factor correction as a kWh saving. Assuming an isolated circuit is dead without proving it, or forgetting stored energy in capacitors and VFDs, are classic safety errors.