Power Distribution

Tested before touched

Never work on energized equipment above 50 volts without documented arc-flash PPE for the incident energy at that location. Verify absence of voltage on all three phases with a known-good meter, on both the equipment and the meter itself. Known-good means you tested the meter on a live source before and after. Keep one hand in your pocket when probing a panel. Shock paths across your chest are the lethal ones.

What breakers trip and why

A tripped breaker is an event, not a nuisance. Something drew current the breaker did not expect. Reset it without investigating, and you might be resetting the symptom of a failing motor or an insulation breakdown that will fault the whole feeder next time.

• A recurring branch trip on the same circuit: check load changes, loose terminations, and developing insulation breakdown.
• Main breaker trip on a hot day: load may be exceeding what your service can carry. Document the current.
• Ground-fault trip on a motor that is fine: cable insulation or a leaking junction box upstream.
• Any breaker that trips differently on cold days than hot days: thermal element drift or load profile change.

Thermography pays for itself

An annual infrared scan of every MCC, panel, and terminal block finds the hot spots that become tomorrow's fault. Loose lugs. Corroded connections. Overloaded branches. A thermography contract costs less than one emergency service call, and the report gives you a punch list for the next planned outage.

The study nobody updates

Arc-flash labels are only accurate if the coordination study behind them is current. Every new transformer, generator, or major motor changes the available fault current at downstream points. If your labels were last updated before your last plant expansion, they are wrong. That means your PPE selection is wrong. Fix this before someone gets hurt.