UL 508 certification

UL is a safety standard certification aimed at standardization related to functions and safety of materials, equipment, products and tool sets, certified by the American Underwriters Laboratories.
Tests are conducted based on this safety standard and a certificate letter and mark are issued for the products that pass.

Global manufacturers of equipment such as programmable logic controllers (PLC), power units, uninterruptable power supplies (UPS), and industrial control equipment achieve UL 508 certification for their products.

Within this unit certification, the parts mounted in the unit are also defined by UL 508.
Specifically, switching devices including mechanical relays and solid-state relays compliant with the UL 508 standard are desired. General-purpose photocouplers such as logic output optocouplers are not within this scope, but photorelays belonging to the Solid State Relay product group are within the scope, and need to adopt it.
For Solid State Relays (SSRs) the resin temperature constraint is defined as a 105°C upper limit. ^{[Note 1]} The following Toshiba photorelays (a MOSFET output type of solid-state relay) are certified by UL 508, corresponding to NRNT. ^{[Note 2]} They can be used up to this temperature limit.
By using our UL-certified products, you can manufacture control equipment conforming to UL standards, and can secure the temperature design margin of solid-state relays.