ESL StormSwitch™ – Keeping the Power On

The damage caused during this historic hurricane season serves as an unfortunate reminder of the need for contingency planning.  From everyday citizens to public institutions, the impact that the barrage has had on communities in the path of the storms will be felt for years to come. The amount of people left without power during this hurricane season is unprecedented; according to the U.S. Department of Energy an estimated 13 million people have experienced sustained outages in the U.S. mainland, Puerto Rico and The Virgin Islands this season. As recovery efforts continue, many ESL StormSwitch™ manual transfer switches are operating in the affected areas to help provide backup power to critical facilities, banks and gas stations.

For more information on how ESL can help be prepared for the next power outage click here.

ESL would like to wish all those affected by the natural disasters a speedy recovery.

ESL actively supports the efforts of the American Red Cross. If you would also like to make a donation to help with relief efforts click here.

Prevent Backup Power Failure – Use UL 1008

Use UL 1008

To ensure the safest and most reliable transfer switch equipment is purchased, the UL 1008 requirement should be included into project specifications. Whoever is responsible for the transfer switch selection process should be aware of criteria that helps classify each UL Listing.

Why UL Listing Matters?

In order to minimize the chances of backup power failure, it is important to make sure that transfer switches and other electrical equipment are properly certified. The UL 1008 Listing is not just a transfer switch performance standard; it is an industry standard for design and construction certification. In order to receive a UL 1008 Listing, a transfer switch must undergo rigorous testing by the independent certification agency.

UL 1008 standard was established by Underwriters Laboratories to help protect against transfer switch dangers and failures. Since its inception, the UL Certification process and standard have been modified and updated on a regular basis. The 7th Edition of UL 1008, which became effective in 2014, resulted in significant changes to the short-circuit ratings shown on all transfer switch products within the industry.

The additional requirements now include:

  • Withstand and close on ratings (WCR) covering severe fault currents
  • Bolted faults and short circuits to ensure the device can carry rated currents
  • Endurance tests which record performance of the transfer switch at each ampere level

The File number is located on top of (or next to) the UL mark; which is identified with the letters “UL” inside a circle and the word “Listed.”

When a transfer switch has successfully passed all of UL’s tests, the manufacturer is then permitted to label qualifying products with the UL mark. The UL 1008 transfer switches are given one of three labels:

  • Non-automatic transfer switch
  • Automatic transfer switch
  • Transfer and bypass isolation switch

Know How to Identify the UL Mark

After passing the tests, UL Listed products are required to carry a marking to identify the Listed company. A (label on a) transfer switch can consist of the company name, a trade name or trademark, or the Listee’s UL file number.  The File number is located on top of (or next to) the UL mark; which is identified with the letters “UL” inside a circle and the word “Listed.”

Misconceptions with UL Certification

Knowing there is a lack of education in the market, many companies will state their device “meets UL standards.” This does not mean it was tested and is “UL Listed”.  When you are evaluating products, look for the logo and category code.  This code can be used to verify the listing and the standard to which it was evaluated.

Below is a list of common UL Listings associated with transfer switches and emergency power connection equipment.

UL 1008   Transfer Switch Equipment
UL 1008 is specifically designed for transfer switch equipment.  Products with a UL 1008 certification means the whole assembly is certified and has undergone rigorous testing to ensure performance, safety, and reliability.  Non-Automatic transfer switches that are Listed under the UL 1008 standard are evaluated in accordance with Articles 517-Health Care Facilities, 702-Optional Standby Systems of the National Electrical Code (ANSI/NFPA 70) and the National Fire Protection Association Standard for Health Care Facilities (ANSI/NFPA 99). The inspection process is also easier when emergency power transfer switch equipment is UL 1008 Listed.

UL 1773 Termination Boxes
This standard is intended for applications that are wired via terminals (usually permanent) and does not contain switching equipment.

UL 98 Enclosed Dead-Front Switches
The UL 98 standard applies to double throw or knife edge switches (air switches), and does not allow the incorporation of circuit breakers.

UL 67 Panelboards
This standard does not apply to transfer switch equipment. UL 67 covers panelboards for the control and protection of electric lighting and appliance branch circuits, and power circuits, including feeder distribution panelboards.

UL 50 Enclosures for Electrical Equipment, Non-Environmental Considerations
A UL 50 Listing only certifies that the actual box is UL Listed for a specific environmental condition (Type 1, Type 3R, etc.).  This does not mean that the whole assembly (enclosure plus components) has undergone testing for the intended application.

Let ESL make your job easy! Download our UL 1008 Listed Manual Transfer Switch specifications for engineers.

Are You Ready for the 2017 NEC Updates?

Have no fear, ESL is here! ESL’s TripleSwitch is 2017 NEC 700.3 (F) compliant when used in conjunction with an ATS.

According to 2017 NEC provision 700.3(F), legally required systems must be able to connect a temporary source of power for emergency systems which rely on a single alternate source of power which will be disabled for maintenance or repairs. It states, the emergency system shall include permanent switching means to connect a portable or temporary alternate source of power, which shall be available for the duration of the maintenance or repair1.

Watch our recent video to learn how the TripleSwitch has you covered!



  1. Source: NFPA’s 2017 National Electrical Code® Handbook


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ESL On The Move – 2016 Trade Show Recap

ESL Trade Show Recap

In 2016 ESL Power Systems attended over a dozen trade shows across the United States and internationally. Our journey included exhibiting at shows in many different regions geared towards multiple industries served including Intermodal Power, Molded Products, Custom Solutions, Entertainment Power and Emergency Power. ESL‘s expansive participation in industry leading conferences is illustrated on the map above.

(Carson, CA)
ASCE Ports
(New Orleans, LA)
 TOC Americas
(Cancun, MX)
(Salt Lake City, UT)
West Coast Energy Management Congress
(Seattle, WA)
Integrated Port Equipment Seminar
(Miami, FL)
PDC Summit
(San Diego, CA)
(Indianapolis, IN)
(Las Vegas, NV)
Port & Terminal Technology (Charleston, NC)  EGSA – Fall Conference
(Sacramento, CA)
Governor’s Hurricane Conference (Orlando, FL) POWER-GEN International
(Orlando, FL)

Notable highlights from these shows include:

  • ESL assisted with hosting the inaugural Integrated Port Equipment Seminars in Miami, FL. ESL collaborated with TMEIC, Phoenix Terminal Solutions, BROMMA, RTE, Remprex and Conductix to create a seminar focused on educating attendees on container operations of the future
  • Promoting ESL’s new Molded Product Line at the SAIA Show in Indianapolis, IN
  • First public display of ESL’s UL/cUL 1008 Listed 3200A TempTap -Generator Docking Station at POWERGEN International

To see where ESL will land next, visit our trade show page. For more information on any of our products please contact

Do You have an Effective Emergency Backup System?

September is National Preparedness Month.  Is your business ready in the event of an emergency? We can mitigate risk, both to our lives and our property, by being proactive and planning ahead for a disaster.

As a business owner, being prepared means having an effective emergency backup system.  An important step in implementing this system is selecting a manual transfer switch that can quickly and safely be connected to a generator should utility power be out for a prolonged period of time. In ESL’s blog, 6-Ways to Select a Manual Transfer Switch we cover the factors that should be considered when determining which type of transfer switch is most suitable for your business.

Ensure your business will be the one to have the lights on in the aftermath of an emergency…

In addition to a reliable back up system, your company should have a plan. Determine how you’ll get your business back up and running. Make a Check list! Assign responsibilities and determine if additional training is necessary to perform the tasks assigned. Include a backup person responsible for a task if your primary is off site.

Plan regularly scheduled maintenance. Keep your equipment up to standards and ready at a moment’s notice. NEC regional standards provide guidelines for regularly testing electrical equipment. ESL’s TripleSwitch —  a 3-way manual transfer switch —  simplifies load bank testing procedures and also provides a safe way to connect a backup generator in the event a permanent generator malfunctions. Read more about this process in our recent blog on how to Streamline Load Bank Testing.

Ensure your business will be the one to have the lights on in the aftermath of an emergency, ready to serve your customers at a time when demand is high!

Remember, it’s never too late to make sure that you’re prepared for an emergency or loss of power!