All SSR at Celduc Relais tested UL SCCR 100 kA !

Since 2006 all of the products and equipment having the UL 508A need to indicate on the plate the SCCR testing value.

SCCR stands for Short Circuit Current Rating.

So far our relays have been certified according to the UL 508A NRNT2 which was stating a short circuit current of only 5 kA. This value is in fact close to what happens in the large majority of applications as the short-circuit current will be limited by the wires, and the different devices in the circuit.

However some customers require additional approval with higher SCCR, because Solid State Relays may replace electro-mechanical contactors which have SCCR much higher than 5 kV. The main concern in this case is about the safety of Personnel. This means that in a system where SSR are used, if a short circuit occurs there must be absolutely no risk of injuries nor risk of fire. The SSR itself may die (coordination type 1) but it must remain harmless to the persons working around, no explosion, no fire !

In the UL 508A this is called supplement SB. These tests will simulate short-circuit conditions occurring high in the circuit and/or mistakes in selecting the protection devices like fuses. In the supplement SB requirements, for one size class of fuses, tests will be made with the higher current rating in this size class. In this way, if there is a mistake in rating within one size class, system will be safe in any case.

Lately all of the SSRs made by Celduc Relais have been tested in the Mersen lab (former Ferraz) in the USA with a short-circuit current of 100 kA !

This part of the UL508A is not mandatory but it proves that products made at Celduc Relais are not only of unrivalled quality but also very safe for operators !