UL 891 Switchboards Standard: An Overview

UL 891 covers switchboards, which are electrical devices that distribute electrical energy from one or more main sources to different load circuits.

In this guide, we explain what importers and manufacturers must know about UL 891, including its scope, where you can purchase UL 891, and information about laboratory testing.

Notice that this guide is written only based on publicly available information on this page. You need to buy the standard in order to access the contents of UL 891.

What is UL 891?

UL Solutions, known previously as Underwriters Laboratories, developed UL 891 – Standard for Switchboards.

UL 891 covers dead-front switchboards, that is devices that do not have any live parts that are exposed on the front – rated at a maximum of 1,000 V. Also, the standard covers switchboards that are meant to be used pursuant to the requirements in the following electrical codes:

a. National Electrical Code (NEC), ANSI/NFPA 70 (United States)

b. Canadian Electrical Code, Part I (CE Code, Part I)

c. Mexican Standard for Electrical Installations (Utility), NOM-001-SEDE

In the US, the American National Standards Institute (ANSI) has approved UL 891.

Additionally, the Canadian Standards Association (CSA) developed and published CSA C22.2 No. 244:19, under which UL 891 is referenced. The standard is also referenced by the Mexican standard NMX-J-118/2-ANCE.

Which products are covered by UL 891?

In general, a switchboard is a piece of equipment that is designed to help control the supply of power in a building, by distributing the energy among a number of load circuits that are able to handle the electricity supply.

Although the standard’s page doesn’t provide any examples of covered devices, this website markets the following types of switchboards as compliant with UL 891:

• General purpose switchboards
• Fusible switchboards
• Commercial metering switchboards
• Draw-out molded case switchboards
• Pow-R-Line XD switchboards
• Integrated facility system (IFS)

Is UL 891 mandatory in the United States?

Standards are often voluntary. Sometimes governmental regulations may make incorporate them, in which case abiding by the standards becomes mandatory to meet the regulation’s requirements. According to our knowledge, this is not the case for UL 891.

However, the standard is designed according to the requirements of the National Electrical Code (NEC), which is a collection of standards that offer guidelines on how to safely install electric wiring in the US so that electrical accidents such as fires are prevented.

Thus, compliance with UL 891 might help importers and manufacturers of switchboards to fulfill the requirements of the NEC.

Scope

UL 891 covers dead-front switchboards that:

a. Have a net electrical output of 1,000 V or less, and

b. Are used on electrical circuits that can handle 200,000 A or less in short-circuit currents

UL 891 does not cover the following types of dead-front switchboards:

a. Switchboards that have a short-time current rating

b. Preset and dimmer control switchboards for theaters

c. Live front switchboards

d. Railway control switchboards

e. Electrification switchboards

f. Constructions meant to only receive motor control center units

Where can I buy UL 891?

Below we list some websites where you can purchase the standard, in order to access its contents.

standardscatalog.ul.com

• Secure PDF and Hardcopy Combo: USD 897
• Secure PDF (Read Only): USD 716
• Premium Hardcopy: USD 897

global.ihs.com

• Hard copy: USD 897

webstore.ansi.org

You can purchase a PDF version of UL 891 on ANSI’s website through a Standard Subscription.

beuth.de

a. PDF download: 689.60 EUR (with VAT) or 644.49 (without VAT)

b. Hard copy: 863.9 EUR (with VAT)

techstreet.com

• Hard copy: USD 897

Lab Testing

In this section, we explain whether lab testing against UL 891 is mandatory, and how much it may cost to get your product lab tested.

Is UL 891 lab testing mandatory?

As mentioned previously, UL standards are generally voluntary in the US.

However, it may be necessary to subject dead-front switchboards to laboratory testing against the requirements in UL 891 if those switchboards need to be installed per the guidelines in the NEC.

Having said that, the UL 891 General Coverage Program explains that switchboard products may not need to undergo substantial testing processes, especially when it comes down to short circuit and temperature tests.

This goal can be achieved by:

a. Using a combination of UL Listed and UL Recognized components

b. Respect the required design parameters, quality control processes, and order guidelines under UL 891

You can learn more about the program on this page.

How much does UL 891 lab testing cost?

The price of having your switchboard tested depends on factors such as the complexity of your product or even the location where the switchboard can be tested.

Though we cannot find publicly-listed prices for UL 891 lab testing, you can contact any of the companies listed below for a quote.

UL 891 Lab Testing Companies

Below we list a few companies that offer testing services against UL 891.

UL Solutions

The UL 891 General Coverage Program offered by UL Solutions allows manufacturers to produce their custom products and subsequently certify them and apply the UL Mark directly in their factories, without having to send samples of the complete product to a UL facility for testing purposes.

Intertek

Intertek operates as an OSHA-approved Nationally Recognized Testing Laboratory (NRTL) in the United States that is able to test dead-front electrical switchboards against the requirements established in UL 891.

It also offers consulting, design, and certification services against UL 891 and other standards relevant to switchboards.

Canadian Standards Association

The Canadian Standards Association, one of the three standards developing bodies that published CSA C22.2 No. 244:19, under which UL 891 is referenced, provides testing services against the requirements of UL 891.