QO / I-Line

A burning smell in a panel almost always means a loose connection arcing under load. De-energize, locate the discolored wire or terminal, re-terminate, and torque to spec.

A hum or buzz from the panel is usually a loose bus bar connection or a breaker under high harmonic load. Locate the noisy component with a listening scope and re-torque the bus connections.

Corrosion inside a panel means moisture is getting in. Find and seal the entry point, clean the corroded components, replace anything with green or white deposits on the terminals, and upgrade the enclosure rating if needed.

Flickering lights or indicators fed from a QO panel usually trace to a loose neutral connection. Measure neutral-to-ground voltage, locate the loose lug, and re-torque.

Intermittent total power loss points to the main breaker or the upstream supply. Check supply voltage first, then swap the main breaker if voltage is steady upstream but the panel drops intermittently.

Thermal cycling loosens breaker terminals and neutral lugs over years of service. A scheduled torque check every 3 to 5 years prevents arcing failures. De-energize, re-torque every lug, and document.

Overheating inside a QO panel is a fire precursor. Use a thermal camera to locate the hot component, identify whether the cause is undersized wire or high load current, and correct it before returning to service.

Repeated breaker trips mean the circuit is overloaded or the breaker is deteriorating. Measure the load current, compare to the breaker rating, and replace any breaker that trips at or below its rated amperage.