Certification to UL 2202 - Part I

14 Feb 2013

There are several design types or protocols for DC chargers, all of which can be tested and listed according to UL 2202 and NEC requirements. One common system currently deployed in the U.S. is the CHAdeMO Quick Charger.

There are several design types or protocols for DC chargers, all of which can be tested and listed according to UL 2202 and NEC requirements.  One common system currently deployed in the U.S. is the CHAdeMO Quick Charger.  This protocol utilizes CAN-bus communication and a set of interlock connections to establish battery charging, and is deployed primarily by Japanese automotive manufacturers.  The recently released update to SAE J1772 details design and operational requirements for various levels of DC charging, utilizing a PLC (Power Line Communication) in addition to the interlocks and PWM pulses already defined for AC charge stations.  This is also being incorporated into the IEC 61851 and 62196 revisions, such that most U.S. and European manufacturers will utilize this harmonized protocol, although no production vehicles are on the road as of writing this article. Some proprietary systems, such as Tesla's "supercharger" system, which is not directly compatible with either CHAdeMO or SAE J1772.  On board chargers, in contrast, may use any or none of these protocols for the output circuit, but must be compatible with an NEC-compliant charge station for its input power.  In any case, neither the National Electric Code, nor UL 2202 are dependent on the protocol, but rather on the safety features defined in Article 625 of the NEC.

Certification options
There are several certification options for U.S. installations of EV Battery Chargers. Full certification (aka listing) of a specific model is the most broad-based method of ensuring compliance throughout the production run of a system.  However, as the EV market is still evolving, EV battery chargers are being installed in ones and twos, in limited markets.  As such, full certification may not provide the flexibility to iterate the system design or deploy prototype/demonstration models.  In those cases, a field label may be employed.  A field label focuses on the specific installation conditions of one unit, and is not transferable to a new location or other models.  This system allows the manufacturer to demonstrate compliance with the NEC, and satisfy local building codes and electrical inspector requirements in a much shorter time-span. 

For cases where a manufacturer may be importing a design already in use overseas (such as a Japanese CHAdeMO model being installed in the U.S.), the field label option may be more feasible, but the manufacturer should have confidence in the system design and installation prior to delivering the system.  In these cases, a Preliminary Design Review (PDR) may help reduce potential delays due to non-conformances.  Through the PDR process, an NRTL engineer will review the product design and intended installation, and compare to the relevant safety standards and NEC clauses.  As a result, non-conformances can be identified and remedied prior to delivering the system, the field label inspection, or full certification submission.

Stay tuned for Part II, which will outline all relevant U.S. and Canadian requirements for testing EVSE to UL 2202. In the meantime, take a moment to read more about UL 2202. You also can leave a question below and one of our experts will get back to you.