Technical Specifications / Parameters Parameter Specification Model Fisher 8540 Type Displacer-operated, Magnetic Snap-Action Switch Switching Element Single-Pole, Double-Throw (SPDT) snap switch. Electrical Ratings Typically 15 A @ 125/250/480 VAC; 0.5 A @ 125 VDC. (Confirm with specific product data sheet). Enclosure Ratings Standard: NEMA 4, 7, 9. Explosion-proof for Class I, Division 1, Groups B, C, D; Class II, Division 1, Groups E, F, G. Process Connection Top Mounting: 2-inch or 3-inch NPT or ANSI Flanged. Side Mounting: 1-inch or 1.5-inch NPT or ANSI Flanged. Materials of Construction Body/Chamber: Carbon Steel, 316 Stainless Steel, Alloy 20, Hastelloy C. Displacer: 316 Stainless Steel, Hastelloy C, Teflon®-coated. Internal Parts: 316 Stainless Steel, Alloy 20, Hastelloy C. Pressure Rating Up to ANSI Class 2500 (depending on housing size and material). Temperature Limits Standard Switch: -40°F to +165°F (-40°C to +74°C) High-Temp. Switch: Up to +750°F (+400°C) with extended stem/chamber options. Set Point Accuracy Typically ±0.125 inch (±3.2 mm) of the set level, depending on specific gravity. Specific Gravity Range Typically 0.15 and higher. The minimum specific gravity determines the required displacer length. Weight Varies significantly with size and construction (e.g., 30 to 150 lbs / 14 to 68 kg).
