EVSE emits a loud humming or buzzing noise during charging, louder than normal contactor hum.

Safety first: Turn off power before tightening or moving internal components.

• Step 1 – Identify source: Carefully listen to locate whether the noise comes from the contactor, transformer, or enclosure panels.
• Step 2 – Tighten mounting: With power OFF, tighten the screws securing the contactor and any transformers to the backplate. Add lock washers if needed.
• Step 3 – Check voltage: Measure supply voltage under load. Low voltage can cause coil chatter; correct any supply issues.
• Step 4 – Damping: Add vibration-damping washers or pads between noisy components and the mounting surface.
• Step 5 – Replace contactor: If the contactor hums excessively despite correct voltage and tight mounting, replace it.