Microswitches are halogen-free and flame-retardant
The established D4 series of snap-action switches by ZF Electronic Systems are now available in halogen-free flame retardant versions which meet the harmonised UL/EN 61058 standards.
They can be used in refrigerators, freezers and air conditioning equipment which use the new, more environmentally friendly refrigerant, which is however flammable.
The T85 version of the D4 series snap-action switches are constructed from black plastic material and have been certified for ignition protected components for use in refrigeration and air conditioning equipment per UL Standard 121201, CAN/CSA C22.2 and IEC 60079-1.
The D4 series snap-action switches have an increased tracking resistance of PTI 300, a high functional reliability, and excellent switching precision, says ZF. Using application-specific contact materials for switching currents from 0.1 to 21A at 250V AC, the switches offer superior contact reliability, claims the company and can be coupled with several available actuators and mounting points for many different applications.
The switches conform to IEC 60335-1 requirements: GWFI at 850 degrees C, GWIT at 775 degrees C and GWT 750 degrees C. They have been designed to operate over an ambient temperature range from -40 to +150 degrees C.
