Service Rated Connector Update, Cord Connected EVSE and Determining the Scope of an OSHA Nationally Recognized Testing Laboratories (NRTL) Recognition

UL Question Corner
UL Question Corner

Question #1

Please provide an update on where I can easily find wire connectors that are Listed (Certified) for splicing or tapping conductors on the line side of service equipment as required in the National Electrical Code® (NEC®) 230.46.


You can now locate the names of all manufacturers and links to their UL Solutions Listing (Certification) information on the Code Authorities page of at Bookmark this page to stay up to date on wire connectors Certified (Listed) for use on the line side of service equipment. This option is in addition to the approach described in the IAEI News Spring 2023 UL Solutions Question Corner.

Question #2

Are UL Listed (Certified) level 2 electric vehicle (EV) chargers rated 48A permitted to be cord and plug connected with a NEMA 14-50 (50A) plug to connect to a 14-50 (50A) receptacle?  I frequently see them for sale online.


No, UL-listed (Certified) cord and plug-connected level 2 EV chargers – also referred to as electric vehicle supply equipment or EVSE – rated at 48 amps are not permitted to be supplied with a 50A-rated plug and receptacle. UL Solutions Lists (Certifies) EVSE for compliance with ANSI/UL 2594, the Standard for Electric Vehicle Supply Equipment. This standard requires attachment plugs to be rated 125% of the EVSE rating. An EVSE supplied with a NEMA 14-50 50A rated plug would only be permitted on an EVSE rated maximum of 40 amps.

NEC® Section 625.6 requires all EVSE to be listed. The EVSE rated 48A with a 50A plug offered for sale online most likely did not actually achieve a certification.

UL Listed (Certified) EVSE can be found in product category Electric Vehicle Supply Equipment (FFWA). The guide information and Listings (Certifications) for FFWA can be located on UL Product iQ® at; enter FFWA at the search field.

Question #3

I have encountered some skid-mounted equipment outfitted with safety-critical equipment that appears to be missing appropriate North American listing (certification) marks and electrical ratings.  The manufacturer says the listing (certification) organization investigated the safety critical equipment as part of the listing (certification) of the skid-mounted equipment. It doesn’t pass the smell test to me. How can I determine if a listing (certification) organization is recognized as qualified to test and certify to a standard?


One way to determine whether a certification organization is recognized as having the credentials to certify to a certain safety standard is to verify that the organization is first an Occupational Safety and Health Administration (OSHA) Nationally Recognized Testing Laboratory (NRTL) and that the organization’s OSHA NRTL scope covers the standard in question.

Through the NRTL program, OSHA recognizes private sector organizations as being capable of certifying certain products to determine that they meet the requirements of specific safety standards.  An NRTL recognition results from OSHA’s assessment of the laboratory’s capability to test, evaluate, and certify to a specific set of product standards related to workplace safety.

OSHA publishes a list of current NRTLs and the list of standards within each NRTL’s scope of recognition on the OSHA website at

An NRTL may only certify products to the specific product safety test standards included in its scope of recognition. UL Solutions has the broadest scope of recognition of all NRTLs, which you can review at For more information on the OSHA NRTL program, visit

If you believe an organization may be certifying products outside the scope of their OSHA recognition, you may want to raise the issue directly with the certifying organization. If you still have concerns, you may also consider filing a complaint about the NRTL on the OSHA NRTL website.

If you are having difficulty determining the appropriateness of a standard used for certification, the UL Solutions Codes and Regulatory Services team may be able to assist at or 800-595-9844.

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