Flameproof Adjustable AC Sensing Switch 0.2~30A Self Powered Sensing Switch(Normally Open) Features: Control of various automatic industrial control equipment, flash, buzzer, relay, single chip, or other power load equipment. Widely used in substation, frequency control device, inverter device, electrolytic plating, electric locomotive, street lamp monitoring, coal mine and other need current monitoring automation industry.  Compared with traditional transformer and thermal protector, it has the advantages of high accuracy, stable performance and long service life. Using the electromagnetic mutual inductance principle of current, the advanced switch output detection, monitoring and protection alarm type products without power supply technology are adopted. An ideal choice for automatic industrial control equipment and electric power monitoring. The current-sensing switch is for safe, convenient monitoring or detecting the current of electric equipment. Specification: Power Supply:Self-Powered,No External Power Supply is Required. Starting Current / Frequency Range: 0.2-30A, 40-400Hz Startup Time: <0.1 Seconds Switch Contact Capacity: Maximum: 0.5A@12-240VAC/DC Overload Capacity: +100%@30A Threading Hole Diameter: 9mm Indicator Light: Red and Green Installation Form: Flat Installation Shell Material: Fireproof ABS Working Temperature: -10~55 °C Working Humidity: 0-95%, No Condensation IP Rating: IP30 Size:46 x 65 x 25mm / 1.81 x 2.56 x 0.98in Package List: 1 x Sensing Switch 1 x Users Manual(Chinese & English)