What is the cURus Approval ?

The solid state relays and contactors made by celduc® relais are manufactured in compliance with cURus standard. Today we will give you more clarification about cURus approval.


The cURus mark indicates that our products meet Canadian and U.S. safety standards.


cURus is an approval from the UL, also named “UL recognized”

“UL” (for Underwriters Laboratories) is the name of the safety certification company, and they offer different certification types and levels.

The UL certification mark is one of the most highly recognised symbols, ensuring that a product is guaranteed to meet the safety and quality standards of products in the United States and Canada, making it highly competitive for the free movement of products in international markets.

UL certifications are voluntary, although, due to their prestige, they have been considered necessary for many electric and electronic products, generating trust and peace of mind in consumers. When we find a product with UL certification, it means that the UL independent laboratory carries out regular and continuous audits on manufacturers, as well as tests on representative samples of these products taken from the market, verifying that they satisfactorily meet the requirements established in the standards in force.

For Solid State Relays, the UL main certification is the cURus, also called “UL recognized”.

A UL CCN (Category Control Number) is the code that represents the Product Category (Category Description). For our Solid State Relays, UL category is NRNT2 means switches, industrial control-component (relays category for standard industrial loads).

This category covers magnetically operated, electromagnetically operated, manually operated and solid-state switches intended for use in nonmotor circuits other than motor-control circuits.
For motor you need to comply with CCN NMFT (Motor Controllers, Mechanically Operated and Solid-state – Component).

The digit after NRNT gives you the type of certification:
blank = listed
2=recognized
7=Listed for Canada
8=Recognized for Canada

NRNT2 is a UL recognized certified product.

Meaning of c UR us

« c » means that the products with this type of mark have been evaluated to Canadian safety requirements

« us » means that the products with this type of mark have been evaluated to US safety requirements

« UR » means UL recognized

« UL » means UL listed


What are the differences between UL Listed and UL Recognized ?


Most common UL certifications are the “UL Listed” and “UL Recognized” marks. However, the meaning of these two marks is sometimes misunderstood and we herewith try to explain their differences.

  1. The UL Recognized Component Mark means that the product has been tested as a component. These components will later be used in complete end-products or systems. Some additional installation precautions may be required. The devices covered under this category are incomplete in certain constructional features or restricted in performance capabilities and are intended for use as components of complete equipment submitted for investigation rather than for direct separate installation in the field. THE FINAL ACCEPTANCE OF THE COMPONENT IS DEPENDENT UPON ITS INSTALLATION AND USE IN COMPLETE EQUIPMENT SUBMITTED TO UL.
  2. UL Listed is for stand-alone products. UL Listed is the more stringent of the two and is recommended if the device is installed directly in a Division 2 or Zone 2 hazardous area. If the device is being installed in a larger system that will provide additional protection then you might consider UL Recognized.


File number

For solid State Relays cURus, we have 2 different files :

  • NRNT2.E69913 : Switches, Industrial Control – Component
  • NRNT8.E69913 : Switches, Industrial Control for Canada- Component


Conditions of Acceptability

Consideration is to be given to the Conditions of Acceptability specified in the individual Reports when these components are employed in the end-use equipment.


Our Solid State Relays have successfully obtained the UL SCCR 100kA approval

UL SCCR standardUL SCCR 100kA certification is another certification from UL, which we have.
In the UL508A standard, the estimated short circuit current rating is known as the SCCR: Short Circuit Current Rating. On April 1, 2015, our solid state relays successfully attained 100kA UL SCCR certification. In fact, some of our customers request additional certification with an SCCR greater than 5KA in accordance with supplement SB, an appendix to UL 508A.


To get the full details, you can refer the UL website directly and select “celduc” in company name.