Author: Erika Thorson

3 Reasons Why UL 1008 Should Be Specified

Erika Thorson

ul-3-reasons

When comparing NRTL Listings of different products, it is important to know what the appropriate UL standards are and how they apply to your specific application. You may not always be purchasing what you think you are purchasing. UL 1008 was specifically created for transfer switch equipment. Products with a UL 1008 certification ensure the complete assembly is certified and has undergone rigorous testing to validate 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 local inspection process by the AHJ is typically much easier when emergency power transfer switch equipment is UL 1008 Listed. So what are some basic reasons to purchase UL 1008? How about these three…

  1. Your UL 1008 listed Manual Transfer Switch will be listed the same as an Automatic Transfer Switch unit. This means continuity of Listing in all your transfer switch designs.
  2. No need to “reinvent the wheel”. With a UL 1008 listed transfer switch for your project, there is no need to verify if your design meets all the requirements for a transfer switch. This should shorten your design time on your project.
  3. By specifying a UL1008 Listed unit, you are assured that the unit supplied is not just a UL 50 enclosure and/or UL Listed components but has been tested as a complete unit. AHJ are becoming more aware that a manual transfer switch should be listed the same as an automatic transfer switch since they perform the same basic function.

When there is a proper solution why go any other way? It just makes sense!

ESL’s line of emergency power connection equipment for commercial and industrial applications is UL/cUL 1008 Listed for StormSwitch® – Manual Transfer Switches up to 3000A, TempTap® – Generator Docking Stations up to 3200A, and TripleSwitch® – 3-Way Manual Transfer Switches up to 3000A. To get a quote on your next project contact us!

ESL’s eTRUconnect Refrigerated Truck-trailer Shore Power

Erika Thorson

ESL’s UL Listed patent pending eTRUconnect™ PS Series provides safe utility shore power to electric or hybrid refrigerated units on truck trailers, eliminating emissions while loading/unloading or idle. Connecting electric or hybrid refrigerated units to shore power eliminates the need of running onboard diesel generators/engines to keep the cargo within the optimal temperature range. This results in significant savings attributed to much lower electric energy cost. eTRUconnect’s, safe and simple connection and disconnection procedure allows truck operators to use the system while minimizing the risk of injury and the liability to the facility owner. ESL’s eTRUconnect is the ideal solution for distribution centers, warehouses, grocery stores and truck stops. Watch our video to learn more!

Designing a Safe Reefer Connection: Part 2

Erika Thorson

Designing a Safe Reefer Connection

Increasing safety

While little has changed in the construction of the receptacles themselves over the years, ESL is constantly challenged to find new solutions that meet unique customer safety and operational requirements. Usually terminal operators have limited or no control over the maintenance and standards associated with male plugs on reefer container cables, the quality of which varies considerably. A male plug with water and salt ingress can “flash” outwards into the operator when the interlock actuator is engaged. In order to energize a receptacle from a safe distance, ESL designed a rear-actuated receptacle that removes this safety risk by requiring the operator to engage the actuator rod from behind the assembly enclosure, out of the way in case of a flashover. Since the development of our rear-actuated receptacle, ESL has installed systems at terminals in Philadelphia, Nairobi and Vancouver. In Philadelphia, ESL added LED lights on the rear of the enclosures so operators can see they have energized the correct receptacle.

Damage control

Properly treated and maintained, a safety-interlocked reefer receptacle is designed to last many years. The reality, however, is that equipment is often damaged through misuse. In our experience, the number one cause of receptacle damage is “drive-offs”, where the reefer is moved without first being disconnected. This will destroy a nylon or plastic ROA, but not a stainless steel one. Stainless steel ROA’s can be repaired by just replacing the receptacle or swapping out a safety-interlocked outlet from another ROA. In North America, the incidence of drive-offs is such that stainless steel ROAs should be considered as an industry standard. ESL also offers microswitches in the receptacle that signals whether a container is connected, regardless of whether the reefer is energized or not. This information could be sent to the terminal operating system (TOS) and an instruction to move a reefer could be blocked if it is still connected.

If you missed part  of our series  focusing on operating reefers at terminals efficiently click here.

Designing a Safe Reefer Connection: Part 1

Erika Thorson

Safe reefer operations require a receptacle system that exceeds minimum standards in electrical codes.

Designing a safe connection - part 1

Safely connecting and disconnecting reefer containers operating on 3 Phase 440-480v power represents one of the largest safety risks from an electrical hazard at the majority of container terminals. Reefer receptacles are designed and listed to electrical safety standards of UL and CE self-certification, but these only “certify” that the receptacle can carry the required electrical load. Other standards, such as IEC 60309-1 and 60309-2 cover configurations of the plug and receptacle and ensure compatibility. It is widely accepted that dealing with 480v, 32A supply presents a safety (and liability) risk and that the standard is to have interlocked connections. A safety interlock is a mechanical or electrical device that prevents a receptacle from being energized unless the male plug is properly engaged and disconnects the power supply automatically as the plug is removed. Although the safety interlock design prevents operators from “making” or “breaking” under load, it is not required under electrical codes and in some cases, terminal construction contractors look to install non-interlocked receptacles, which pose a higher safety risk to operators, but offer cost savings. Some situations arise where contractors facing strict budgets try to install non-interlocked receptacles. The objective is to make sure interlocked receptacles rather than “complying” receptacles are specified when projects are tendered. As far as the design of the interlock is concerned, there are several options. ESL’s standard system detects the ground pin of the male plug before allowing the unit to be energized, whereas other designs interlock off the key on the side of the plug. ESL believes the ground pin is the safer option. Additionally, in some markets, plug keys are frequently “shaved off” to allow a 32A plug to mate with a 30A (non-interlocking) receptacle, meaning the 32A male plug must be replaced elsewhere in the supply chain in order to safely connect to a receptacle that interlocks at the key.

Operating Efficiently

Another important aspect of reefer power supply is designing the receptacle system so the terminal can perform reefer operations efficiently. In considering the layout of the reefer area(s), terminal management has to weigh the initial costs of installing more reefer outlet assemblies (ROAs) against the labor costs of managing cabling from fewer centralized ROAs. A reefer rack structure is typically six or seven containers wide and some operators opt for an ROA with six or seven receptacles mounted centrally. This configuration is more prone to tangled reefer cables, which present tripping hazards and the chance of disconnecting the wrong cable. Terminals with wider reefer racks may even require extension cables to reach the outer containers. Installing more receptacles per ROA is ultimately a cheaper solution, but a trend towards two and three-gang ROAs due to operational efficiencies is growing. Demand is also increasing for two LED lights, one to indicate line power is available to the ROA and a second to show that the receptacle is energized and power is flowing. If the first LED is not showing, the operator will know immediately that there is an upstream power supply problem. An available option is the incorporation of an equipment ground fault protection (GFP) device on an outlet module to isolate the effect of a phase to ground short. ESL has frequently been asked to incorporate a simple ground fault protection device that can isolate a fault at the receptacle and prevent upstream switch gear from being tripped by a short. Terminal design engineers need to take into account that reefers generate ground currents during the defrost cycle, so the GFP devices should be selected and set at a value above the defrost cycle ground currents to avoid nuisance tripping.

Read part 2 of our series  focusing on reefer receptacle safety and damage control.