Until recently, almost all current transformers (CTs) used with electric submeters were certified by Underwriters Laboratories (UL) as UL Recognized Components under the XODW standard, using a subset of the requirements from IEEE C57.13 and CSA 60044-1. The key phrase is “UL Recognized Component”. The UL Recognized status meant the CTs were not approved for standalone field installation. UL did approve the use of UL Recognized Component CTs with UL Listed submeters (like the WattNode meter) for field installation.
In the past, the meter approval was generally accepted by the building inspector or authority having jurisdiction (AHJ). But in some cases, inspectors would request a copy of the conditions of acceptability for the current transformers and find that the CTs were not approved for field installation, and so would not approve the job.
UL 2808 CT safety standard
The UL 2808 CT safety standard was released by UL in 2012 under category code XOBA. The 2017 Edition of the National Electrical Code (NEC) requires that field installed CTs used to measure current on the service entrance or branch circuit conductors within panelboards, switchboards, industrial control equipment, and energy-monitoring/management equipment, must be listed (UL Listed).
As the 2017 Edition of the code is adopted by states and other authorities, only UL Listed CTs will be permitted in circuit breaker panels or related electrical enclosures.
The following CT Series sold by CCS are all UL 2808 Listed
National Electrical Code state by state adoption map: Nation Electrical Code 2017 Map