UL 1640 for Portable Power Distribution Systems

Table of Contents

1.0 Executive Summary

2.0 Introduction

3.0 What is UL 1640?

3.1 Overview

3.2 Certification Mark of UL

3.3 Manufacturing Applications of UL 1640

4.0 Becoming a UL Panel Shop

4.1 Advantages and Benefits

4.2 Requirements

5.0 Larson Electronics Power Distribution System Solutions

6.0 Conclusion

UL 1640 portable power distribution

1.0 Executive Summary

This report covers UL (Underwriters Laboratories) 1640 guidelines for portable power distribution systems. The paper explores the applications of the standard in various industrial environments, including its associated compliance with specific articles set forth in the National Electric Code, NFPA 70 (NEC). Recognizing the importance of UL listings and its advantages for competitive portable power distribution system manufacturers, the second part of the report aims to breakdown the requirements and benefits of becoming a UL Panel Shop. Portable power distribution system manufacturers, industrial facility operators and engineering professionals may use this paper to reinforce their understanding of UL compliance.

Larson Electronics is a company that specializes in industrial lighting and power distribution products. With over four decades of experience, the brand provides customized solutions for fast-moving businesses in the following sectors: military, government, marine, industrial, entertainment, aviation and hunting. This paper is a reflection of Larson Electronics’ expertise in the portable power distribution space.

2.0 Introduction

Portable power distribution units (PDUs) are robust machines that are commonly found in industrial facilities with challenging power requirements. They regulate and supply power to heavy equipment in locations without adequate, existing power distribution systems, such as construction sites, remote military bases, theatrical stages and movie sets. Portable PDUs may also be utilized to support industrial, large-scale operations in tandem with permanent, high-voltage panels; or the use of multiple devices with different voltage needs in sections of the facility without direct access to regulated power.

For example, workers may rely on a portable PDU to step down exceedingly high voltages to usable voltages, i.e., 110, 120, 220 and etc. Lights, inspection tools, cleaning equipment and other power-hungry devices with varying voltage requirements may be attached to the portable PDU, which is also hooked up to a much larger power source.

According to a report from Indiana Business Center’s publication branch, shipments for power distribution products and transformers are on the rise, with the largest increase between 2002 ($4.9 billion) and 2007 ($7.4 billion). This trend suggests that reliance on PDUs is increasing steadily. To boost safety and best practices during manufacturing, various regulatory groups, such as UL, which is an OSHA-approved, Nationally Recognized Testing Laboratory, have established guidelines for portable PDUs. Specifically, UL 1640 (Standard for Portable Power-Distribution Equipment) closely adheres to NEC guidelines on electrical design and safety.

UL 1640 may be applied in the following sites and locations:

  • Exhibition halls (NEC Article 518)
  • Temporary installations in construction sites (NEC Article 590)
  • Television and movie production studios (NEC Article 530)
  • Carnivals, fairs and similar locations (NEC Article 525)
  • Theaters and television studios where audiences are present (NEC Article 520)

In order to boost the production of high standard portable PDUs, some manufacturers have actively acquired UL Panel Shop Certification. Portable PDUs with UL Approval markings may help ease consumer adoption, compliance and building/equipment inspections. Since UL rulings are generally accepted standards, most inspectors look for serial numbered UL labels during assessment to ensure industrial safety guidelines are adequately observed. Having UL Approved portable PDUs may also decrease the chances of getting one’s equipment installation rejected due to safety concerns.

3.0 What is UL 1640?

3.1 Overview

UL 1640 is a set of requirements that portable PDU manufacturers may satisfy to ensure their design, assembly and configuration standards sufficiently and safely meets the needs of the applicable location. Portable PDUs that meet such guidelines are provided with a special UL marking or listing, which serves as a “stamp of approval” from the institution (more information can be found in Section 3.2 Certification Mark of UL).

Several regulations in UL 1640 are referenced with specific NEC articles. In such cases, the NEC codes serve as recommendations for proper installation of the portable PDU. The NEC is a set of guiding principles, widely recognized by inspection agencies in the United States, that focuses on electrical safety. It is important to consider that NEC compliance is enforced by electrical inspectors; therefore, following UL 1640 guidelines on a manufacturing level does not automatically lead to NEC compliance.

With this in mind, UL 1640 covers specific components found inside portable PDUs, including internal wirings, busbar clamps and enclosures- just to name a few. Furthermore, it elaborates on various testing protocols that exposes possible vulnerabilities of the product. Such testing protocols include (but is not limited to): Dielectric Voltage-Withstand Test, Strain-Relief Test, Corrosion Resistance Test and Resistance to Rain Test. The standard also shines light on the proper application of cable-mounted busbar clamps for use with portable PDUs, i.e., cable terminating to the components must be tied or adequately supported in order to ensure that strain on the conductors is not passed on to the conductor termination found at the busbar clamp. When it comes to partially enclosed, cable-splicing blocks, the components are appropriate for outdoor, damp locations, where the blocks may be exposed to rain or water (in a non-energized state). Articles 520 and 530 in the NEC elaborates further on such practices.

In Part 4 of the standard, titled “Construction-site Equipment for Temporary Installations in Accordance with Article 590 of the NEC,” the organization emphasizes recommendations for evaluating portable PDUs in construction sites. This chapter lays out the foundation of portable PDU construction, performance and markings, which is applicable to the respective location.

 

3.2 Certification Mark of UL

A primary indicator that the portable PDU is in compliance with UL 1640 includes distinct markings on key components found on or inside the unit. A UL listing mark indicates that the component has undergone comprehensive, rigorous testing. This process requires the portable PDU manufacturer to submit product samples to the regulator. During this step, the samples are closely scrutinized for compliance. Under UL’s Certification and Follow-Up Service, this marking is the only method that is used by the organization to distinguish products that are under this category. Alternatively, portable PDU components may also be “UL Recognized.” Such distinctions indicate that the product passed UL inspection, and was found safe for specific instances during its final application.

A traditional UL Certification Mark is composed of the following:

  • UL symbol
  • The words “Certified” and “Safety”
  • Applicable identifiers that provide relevant geographical data
  • File number

Notes: For busbar clamps, such markings can be found on the smallest unit container in the packaging of the component. Busbar clamps and cable-splicing blocks should only be used by “qualified personnel only,” i.e., “The routing of portable supply conductors, the making and breaking of supply connectors, and the energization and de-energization of supply services shall be performed by qualified personnel only.” (UL Online Certification Directory on Power-distribution Equipment, Portable; Product Markings)

UL-approved portable PDUs may incorporate one of the following product identities (in some descriptions or labels, “Equipment” may be replaced with “Unit”):

  • Busbar Clamp
  • Construction-site Port Pwr-dist Unit
  • Construction-site Portable Power-distribution Unit
  • Open-frame Cable-splicing Block (for partially enclosed, plastic-framed cable-splicing blocks)
  • Port Pwr-dist Unit
  • Portable Power-distribution Unit

In 2013, UL launched the Enhanced and Smart UL Certification Mark and UL Certification Badge system. This new option is designed to streamline product marking through the addition of flexible QR codes and cleaner badge designs. Manufacturers may also customize their own UL markings for added distinction using the Marks Hub. To facilitate QR code scanning, it is recommended to place the Smart UL Certification Mark on an accessible surface on the applicable product. Scanning the QR code using a handheld device, such as a smartphone, will open a web page that displays an image of the product, a short product description, manufacturer information and certification details. Individuals may also key in the Smart ID number located on the UL Smart Mark in the UL website. This option is ideal for individuals who are using desktop computers or tablets.

 

3.3 Manufacturing Applications of UL 1640

The requirements found in UL 1640 can help portable PDU manufacturers comply with UL standards. Because portable PDUs are used extensively in demanding sectors, the guidelines provide key insights on the type of environments the product may encounter.

For example, related products associated with the standard includes equipment alongside of stage lighting systems found in theaters (Stage and Studio Luminaires, Accessories and Connector Strips). This category, covering stage and studio fixtures, equipment and connector strips with 600V ratings or less, meets the limiting scope of UL 1640 (1.4), indicating that portable PDUs that adhere to such recommendations must be “rated 600 volts or less and 1,600 amperes maximum.” Individuals should carefully note that UL 1640 does not extend to portable PDUs that should be mounted on top of or next to a lighting system it is supplying.

UL 1640 also makes several associations with connector assemblies. In particular, the standard specifically cites connector assemblies composed of factory-assembled plugs and cord connectors that are connected to extra-hard service cords (Cord Sets and Power-supply Cords). The guide also references such units that are designed for undercarpet use in large exhibitions (Exhibition Display Units, Accessories).

 

4.0 Becoming a UL Panel Shop

4.1 Advantages and Benefits

Portable PDU manufacturers may ease the UL product certification process by becoming a UL Listed Panel Shop. Establishments that bear this type of certification are allowed to build or mass produce portable PDUs with distinct UL Marks for the United States and Canada. The advantages of acquiring UL Panel Shop status are numerous. Holding such credentials would allow the business to participate in projects or jobs that must be completed by UL shops only.

As mentioned earlier, since UL is one of the most credible regulatory institutions in the United States, inspectors and certifiers may refer to UL product markings during inspection, when checking for compliance with specific standards (for portable PDUs- UL 1640; for industrial control panels- UL 508A and UL 698A [an extension of UL 508A on industrial control panels with intrinsically safe circuits]; and etc.). As a result, some customers are more inclined to purchase UL Listed portable PDUs to decrease the risk of getting rejected due to code violations by a building inspector. From a safety perspective, portable PDUs with UL markings offer peace of mind for businesses that are concerned about safety in the workplace. Should an accident occur involving the UL approved unit, such markings may be used to safeguard businesses from legal disputes involving negligence or non-compliance.

It is crucial to note that manufacturers are not forced to use UL to meet their compliance needs. Companies may also select other Nationally Recognized Testing Laboratories that are recognized by the OSHA, such as Electrical Testing Labs (ETL) Listed Marks from the ETL SEMKO division of Intertek. Like UL Marks, ETL Listed Marks are acknowledged by manufacturers, inspectors and Authorities Having Jurisdiction (AHJs). ETL has decades of experience in the field of product safety testing and certification, with origins going back to a laboratory ran by Thomas Edison in 1896. Establishing that the standards of UL and ETL are the same, the main difference between the two regulating institutions is service.

 

4.2 Requirements

Portable PDU manufacturers that are interested in becoming a UL Panel Shop must adhere to requirements set forth by the organization. Such companies are subject to periodic, random inspections by a UL representative to ensure that it is actively complying with the standards. During inspection, the UL field representative performs manual checks on some of the components inside the portable PDUs. It is vital to consider that inspectors do not closely scrutinize all of the parts and units during the process. Inspections are influenced by the number of UL Labeled products manufactured over a specific time period. The facility used for manufacturing may also be subject to inspection. A UL Panel Shop that manufactures portable PDUs is reviewed using the applicable UL standard for the product (UL 1640). Upon approval, the manufacturer may commence with production and application of UL labels. Any changes to the product after approval would result in re-testing and re-certification.

When it comes to building portable PDUs, the products may only utilize UL recognized or listed parts. Additionally, it would not be possible to have a non-UL shop build the unit from a non-UL shop facility, and have the UL shop inspect and apply UL stickers afterwards- even if the UL shop supplies the materials. This is because UL representatives, in addition to inspecting specific components, also evaluate the manufacturer’s wiring methods, record keeping protocols and other aspects of production. In such cases, not mentioning or leaving out the non-UL shop’s role in manufacturing may lead to fraudulent violations.

 

5.0 Larson Electronics Power Distribution System Solutions

Larson Electronics offers an extensive range of portable PDUs for businesses in industrial sectors. Large-scale facilities may use the company’s three or single phase portable PDUs to power multiple devices or heavy equipment with varying voltage requirements. In addition to portable PDUs, Larson Electronics also provides comprehensive industrial lighting solutions through its line of commercial lighting products; which includes LED lights, explosion proof luminaries, solar powered light towers, hunting lights, corrosion resistant fixtures, truck lights and more.

Below is a shortlist of portable PDUs available from Larson Electronics:

 

6.0 Conclusion

Applying UL 1640 standards when manufacturing portable PDUs is an effective way to add value to one’s products. The standards, which includes references from relevant NEC rulings, are designed to maintain the quality of the unit during the manufacturing process. Due to increased reliance on UL certified products, the organization released updated, web-friendly “smart UL markings” with actionable QR codes.

To increase compliance with UL 1640 and other UL standards, manufacturers may consider becoming a UL Panel Shop. This level of certification can help reduce bottlenecks in the product certification process, allowing the UL Panel Shop to apply UL stickers on its offerings during production. Becoming a UL Panel Shop may improve one’s overall business, because customers are more inclined to purchase UL-approved portable PDUs for peace of mind and safety. Lastly, in addition to UL, manufacturers may seek certification from other Nationally Recognized Testing Laboratories that are acknowledged by the OSHA, such as ETL.

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