Effective September 26, 2017

Standard Information
Standard Number:
UL 1741
Standard Name:
Inverters, Converters, Controllers and Interconnection System Equipment for Use with Distributed Energy Resources
Standard Edition and Issue Date:
2nd Edition Dated January 28, 2010
Date of Revisions:
September 7, 2016
Date of Previous Revisions to Standard:
2nd Edition Revised March 23, 2016
Effective Date of New/Revised Requirements

Effective Date (see Schedule below): September 26, 2017

Impact, Overview, Fees and Action Required

Impact Statement: A review of all Listing Reports is necessary to determine which products comply with new/revised requirements and which products will require re-evaluation. NOTE: Effective immediately, this revised standard will be exclusively used for evaluation of new products unless the Applicant requests in writing that current requirements be used along with their understanding that their listings will be withdrawn on Effective Date noted above, unless the product is found to comply with new/revised requirements.

Overview of Changes: This revision was issued primarily to incorporate the new Supplement SA for Grid Support Utility Interactive Inverters. Specific details of new/revised requirements are found in table below.

If the applicable requirements noted in the table are not described in your report(s), these requirements will need to be confirmed as met and added to your report(s) such as markings, instructions, test results, etc. (as required).

Schedule: So that shipping of products with Listing Marks will not be interrupted, an approximate schedule has been established to ensure Listing Reports are found compliant by Effective Date:

  • January 26, 2017 = 8 Month Report Review – Intertek will review all Reports. Update if compliance is verified or issue Findings Letter/Quote for any re-evaluations needed
  • March 27, 2017 = 6 Month Quote Cut-off – Quotes returned for necessary re-evaluations
  • September 26, 2017 = Effective Date – ATM Suspended for all non-compliant Reports

Fees: An initial review of Listing Report (s) will be covered by a direct billing project and will be invoiced at not more than $1000 per report.

Client Action Required:

Information – To assist our Engineer with review of your Listing Reports, please submit technical information in response to the new/revised paragraphs noted in the attached or explain why these new/revised requirements do not apply to your product (s).

Current Listings Not Active? – Please immediately identify any current Listing Reports or products that are no longer active and should be removed from our records. We will do this at no charge as long as Intertek is notified in writing prior to the review of your reports.

Description of New/Revised Technical Requirements
63InfoDetails (Marking)
63.3.1  New clause added;

When an inverter, converter, or interconnection system equipment (ISE) is intended for connection with an EPS, complies with Utility Compatibility, Section 46, and with IEEE 1547-2003, it shall be marked “Utility Interactive Inverter” or equivalent to indicate the specific document and version of the interconnect requirements to which it complies. Example “Compliant with IEEE 1547a-2014 (Amd. 1)” or equivalent. Inverters that comply with the requirements of UL 1741 Supplement SA, as well as the requirements for a utility interactive inverters shall be marked “Grid Support Interactive Inverter“ or “Grid Support Utility Interactive Inverter“. A reference to the specific standard(s) and version(s) complied with may optionally be added to the marking and shall be included in the installation instructions.
SUPPLEMENT SA New section added;


This new section includes new construction requirements, testing, markings, and instructions for Grid Support Utility Interactive Inverters and Converters (see standard for section details).

CUSTOMERS PLEASE NOTE: This Table and column "Verdict" can be used in determining how your current or future production is or will be in compliance with new/revised requirements.

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