Schneider Electric ZB4BS55 22 mm Yellow Mushroom Head Push Button

Industrial Mushroom-Head Operator

The Schneider Electric ZB4BS55 is a 22 mm yellow mushroom-head push button designed for industrial control panels. Its maintained action keeps the circuit in the selected position until pressed again. Metal construction throughout the head, bezel and base material suits harsh environments where plastic operators could degrade. Panel builders and maintenance engineers specify it for emergency-stop or manual-override stations.

Environmental Ratings Define Installation Limits

The operator carries NEMA 1, 2, 3, 4, 4X and 13 ratings alongside an IP66 ingress-protection class. These standards certify resistance to falling dirt, dripping water, hose-directed spray, corrosion and oil or coolant seepage. Compliance with IEC 60529, IEC 60068-2-6 and IEC 60068-2-27 confirms suitability for vibration and shock-prone machinery. Installations requiring higher-pressure wash-down or submersion fall outside the certified envelope.

Forty-Millimetre Head Balances Visibility

The 40 mm mushroom diameter provides a large, colour-coded target that operators can locate quickly in low light or while wearing gloves. Yellow coding conventionally signals caution or manual-reset functions rather than immediate emergency stop. The maintained mechanism suits processes that need a latched state without continuous pressure. Applications demanding momentary action, smaller cut-outs or different colour codes require a different operator type.