What is the difference between UL listed CT and UL recognized CT

Posted on Nov 24, 2017

What is a UL listed Current transformer (CT)?
1, Marked with UL Listed Mark;

2, Comply with UL2808 of XOBA & IEC61010-1
3, UL listed CTs are free from reasonably foreseeable risk of fire, electric shock, as well as related hazards. 
4, The UL Listed CTs are special designed with the consideration of higher standard of safety, higher standard of material, higher      standard of constructure, insulation etc...

5, UL Listed CTs can be installed directly in the field and do not need to be packaged as part of a larger system that is co-calibrated in the factory.

What is a UL Recognized Current transformer (CT)?
1, Marked with UL Recognized Mark;

2, Comply with the IEC60044-1 or relevant standard;
3, UL Recognized current transformers are marked by the UL Recognized Component Mark. This particular seal is reserved for components or materials that are intended for use in a complete product or system – rather than those that are sold as an end-user product. According to the Official UL Guidelines, “These components are intended only for incorporation into other end-use products that may be eligible for UL’s Listing, Classification or Certificate Service.”

 

Why UL listed CT?

The new NESC code says: If you are going to field-install current transformers (CTs), they must be certified to the UL2018 (XOBA) standard. This is the UL ‘Listed’ Mark:

Changes in the new 2017 edition of the National Electrical Safety Code (NESC) calls for the enforcement of the UL2808 standard (Category XOBA). Now is the time get ahead of the coming inventory problems.

If a CT bares the UL ‘Recognized’ mark, then field installation requires a UL inspection and costly system recertification after installation to retain the UL Listed system’s integrity. This the Recognized mark: