2017 National Electrical Code®: Changes in Overcurrent & Surge Protection

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2017 National Electrical Code®: Changes in Overcurrent & Surge Protection

Mersen recently released a guide to understanding its changes in overcurrent and surge protection in the 2017 National Electrical Code®. These changes are to increase worker safety and help prevent arc flashes.

Arc flashes are the result of a massive release of energy due to an arcing fault between two phase bus bars, neutral or a ground.  This energy discharge burns the bus bars, vaporizing the copper and thus causing an explosion, which destroys everything in its vicinity and creates deadly shrapnel as it dissipates. Short-circuit current ratings (SCCR) indicate what fault current a system can handle without unacceptable damage in the case of a fault. Proper documentation is essential to ensure the available short-circuit current does not exceed the SCCR and that suitable precautions are in place.

We offer Mersen safety solutions to help you comply with the updated code and increase your workplace safety. Mersen’s guide covers nine key changes to the 2017 National Electrical Code®:

  1. Arc energy reduction

    Any fuses rated 1200 A or higher must have their location documented and available. The fuses must also have a method to reduce clearing time if their clearing time is not already 0.07 seconds or less.

  1. Field marking of available fault current

    Industrial control panels, industrial machinery and motor controllers of multimotor and combination-load equipment must have the date the current short-circuit calculation was performed and available short-circuit current rating (SCCR) documented.  If the available short-circuit current exceeds its short-circuit current rating, they shall not be installed. Elevators must also have the maximum short-circuit current clearly marked.

  1. Branch circuit and ground fault protection for single motor power conversion equipment

    Semiconductor fuses and instantaneous trip circuit breakers must now be installed as a single unit if instantaneous trip circuit breakers are permitted.

  1. Short-circuit current rating for elevator control panels

    Elevator control panels must be marked with their SCCR. If the available short circuit current exceeds its short-circuit rating, elevator control panels shall not be installed.

  1. Surge protection for emergency elevator, dumbwaiter, escalator, moving walk, platform lift, or stairway chairlift

    Surge protection shall be provided if the elevator has been designated as supplying an emergency system load.

  1. Surge protection for critical operations data systems

    A cascading protection scheme should be used throughout the entire operations data system.

  1. Surge protection for industrial machinery

    Industrial machinery with safety interlocks are required to have surge protection.

  1. Surge protection for fire pump controllers

    Surge protection was required previously for emergency systems at distribution level, but are now also required in or on the fire pump controller.

  1. Short-circuit current rating documentation and field marking

    Transfer switches can often have several different SCCR, so the rating based on the protective device and settings shall be externally marked.

Want to learn more about the changes in the 2017 National Electrical Code® or how best to implement them in your workplace? Contact your French Gerleman Account Manager or e-mail info@frenchgerleman.com to learn about Mersen safety solutions.


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Product Spotlight: Mersen Surge Protection

Did you know that power related fluctuations cost US companies more than $80 billion a year? Down machines cost you money, time and resources. Instead of spending thousands of dollars to fix or repair your expensive machinery, for a minimal investment, you can protect your sensitive equipment, or your entire facility, from electrical surges.

Most surge spikes occur from within a customer’s own facility. Nearly 80% of all surge problems are directly attributed to power disturbances from a facility’s own equipment. So who is at risk for a surge spike? If you have a facility with motors that are stopping and starting, load panels being turned on and off on a regular basis and other potential power disturbances, then you are at risk for damage.

What types of damage can a surge cause to a facility? Can it really be that bad? The short answer is YES and can be described by the 3-Ds.

  • Disruptive: A surge enters an electronic component, which then in turn, interprets the valid logic command. The result is a system lock-up, machine malfunction, leading to faulty output or corrupted files.
  • Dissipative: This is a repetitive pulsing of short duration energy, which results in long-term machine or system degradation, leading to system replacement sooner.
  • Destructive: This is caused by a high-level energy surge that immediately results in equipment failure, or complete destruction.

Protecting your equipment, and facility, is more important now than ever. At French Gerleman, we carry the Mersen Series SPD units: STXH, STXR, STXP and STXT. Here’s a description of each and how they can help you.

STXH Series:

The Surge-Trap Type 1 STXH is the most compact of the STX series, and meets all requirements for UL1449 Fourth Edition. It is suitable for any 120/240VAC split phase application, and features TPMOV® technology inside, meaning it is the safest product available in its category. Due to the small size, the performance and reliability, the STXH is ideal for HVAC applications and direct mounting to air condition disconnect switches.

Product features and benefits:

  • Designed with the industry leading Mersen TPMOV® technology
  • Compact footprint designed to mate with AC Disconnect Switches
  • LED status indicator
  • NEMA 4X enclosure for indoor and outdoor use
  • Fits 1/2″ knockouts with 18″ leads
  • For use in ANSI/UL Type 1 or 2 SPD installations
  • Features 3 modes of protection (L-N, L-L)
  • 3-year warranty

STXP Series:

The STXP Series offers advanced performance and features over the STXR series, including higher surge capacity and phase LED status indicators. It meets the UL1449 Fourth Edition Requirements and was designed for additional mounting flexibility, including mounting feet and flush-mount capability. Like the others in this line, the STXP features TPMOV® technology inside, making it the safest product available. This product is the perfect fit from service entrance all the way down to an important machine specific control panel.

Product features and benefits:

  • Designed with the industry leading Mersen TPMOV® technology
  • Features enhanced 100kA surge capacity for longer life and higher single impulse withstand
  • Pre-wired with 3′ leads for easy installation
  • Up to 10 modes of protection (L-N, L-L, L-G, N-G)
  • Features a 10-year warranty

STXR Series:

The STXR is the most popular model in the STX range, meeting requirements for UL1449 Fourth Edition. It is ideal for the replacement of obsolete surge arrestors. With a small, compact design and line or load installation flexibility, the STXR series is the perfect fit for branch panels or individual equipment protection.

Product features and benefits:

  • Designed with the industry leading Mersen TPMOV® technology
  • LED status indicator (ON=good, OFF=replace)
  • NEMA 4X enclosure for indoor or outdoor use
  • Fits 3/4″ knockouts with 3′ leads for easy installation
  • Features an optional mounting bracket for surface mount applications
  • Optional audible alarm and remote dry contacts
  • For use in 10 modes of protection (L-N, L-L, L-G optional, N-G optional)
  • Features a 5-year warranty

STXT Series:

The STXT Series is the most advanced of the STX series. It comes standard with EMI/RFI Filtering and surge capacities up to 200kA. It features TPMOV®, with line or load side installation flexibility, making it a great fit for a service entrance all of the way down to each distribution and/or branch panel.

Product features and benefits:

  • Designed with the industry leading Mersen TPMOV® technology
  • Premium 200kA surge capacity for longer life and higher single impulse withstand
  • Includes EMI/RFI filter for cleaner attenuation
  • Features a mounting hub and mounting feet for installation flexibility
  • Optional audible alarm and remote dry contacts
  • Up to 10 modes of protection (L-N, L-L, L-G, N-G)
  • Features a 10-year warranty

Save time and money and stay protected from unwanted surge spikes and equipment failures with the STX Series from Mersen. Interested in learning more about how they can protect your facility? Contact your French Gerleman Account Manager today!


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New Outdoor LED Lighting Surge Protection Solutions from Mersen

LED technology and lighting has taken over the market because of their efficiency, versatility, energy savings and longer life. But why is surge protection needed, particularly in outdoor applications? While they have countless benefits, the technology also has a number of drawbacks, including higher cost of implementation, more complex internal electronics and they are much more sensitive to overvoltages than traditional light sources.

To help extend the life of an outdoor LED luminaire, the use of overvoltage surge protection systems is a cost effective investment to ensure the ROI of LED projects.

Often times people associate SPDs with interior machinery, but with outdoor LED lighting, it’s important to protect your equipment, or your cost savings might go out the window. So what is a surge protection device (SPD)? A SPD connects upstream of the drive, complements the intrinsic immunity of the luminaire, creating a more robust protection against lightning and overvoltages. SPDs protect equipment by discharging the overvoltage to earth, therefore limiting the voltage reaching the equipment.

The three-stage SPD solution from Mersen

  1. Lighting Panel (SPD+POP series)
  2. Pole/Fusebox (STM SLIM series)
  3. Luminaire (STLB series)

Surge Protection in the Lighting Panel
This is the first stage of protection. A two-in-one combined (POP + SPD), it protects against permanent

or temporary overvoltages (POP) is the perfect complement to the typical first stage protection, a type 2 SPD in the lighting panel.

Surge Protection in the Pole/Fusebox

Mersen’s STM SLIM is the new range of LED arresters which provides a solution for installation in fuse boxes (located in the mast of the luminaire) with a DIN rail. It’s perfect for retrofitting.

Surge Protection in the LED Luminaires
These feature STLB Surge-Trap, the best in-line surge protection for LED lighting applications. A single device is suitable for single, split or three-phase applications; can be installed in series or parallel with the luminaire; features leakage current free technology and visual end-of-life indication.  The fastening flange allows the SPD to be installed upright or flat, depending on the space constraints of the luminaire.

Mersen Map

It is certified and suitable for worldwide installations.

Mersen’s Surge-Trap three stage LED solution is ideal in a wide range of outdoor lighting applications, including: street lighting, industrial lighting, public lighting, parking garages/surface lots, stadiums, tunnels and much more. For more information on Mersen’s Surge-Trap LED surge protection, give your Account Manager a call or contact us.


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Mersen New Product Launch: Surge Protective Devices

Your facility is full of expensive, important equipment that you rely on daily. Not only do down machines cost you time, they are expensive and frustrating for your team and customers. That’s why surge protection is a hot topic that you NEED to make sure is addressed.

What types of damage can a surge cause to a facility? The three main types are disruptive, dissipative and destructive.

  • Disruptive is when a surge enters an electronic component which interprets the valid logic command. This causes the system to lock-up and machines to malfunction, which leads to faulty output or corrupted files.
  • Dissipative damage is caused by a repetitive, pulsing of short duration energy, causing long-term machine or system degradation, leading to system replacement sooner.
  • Destructive damage is a high-level energy surge that immediately results in equipment at earlier intervals.

With a minimal investment, you can protect your sensitive equipment or entire facility from surge events. Mersen’s Surge-Trap product line offers a world-class suite of surge protection products designed to keep your facility protected and save you from costly, unscheduled downtime.

Mersen has created six new product lines to address all applications and target markets. They are:

  1. Surge-Trap STXH
  2. Surge-Trap STXR
  3. Surge-Trap STXP
  4. Surge-Trap STXT
  5. Surge-Trap STZ (Internal)
  6. Surge-Trap STZ (External)

Features and Benefits

All devices are Type 1 SPDs making them suitable for all applications from facility service entrances to individual equipment point-of-use. These surge protective devices are designed with the popular, industry leading, Mersen-patented Thermally Protected MOV (TPMOV) technology – the best performing, most reliable surge suppression technology on the market. It also features a wide range of surge capacities to fit any and all applications and target markets.

Each surge protective device is designed with the latest printed circuit board technologies and components for optimized footprint, cost and reliability. They feature options addressing the needs of new and retrofit facility installations, including LED status indicators, surge counters and disconnect switches.

Mersen surge trap

Nema surge

Why should you choose Mersen? Almost all Mersen SPDs feature their patented TPMOV technology, a fail-safe surge protection solution that eliminates the need for additional wiring, fuse components and costly installation time. As a result, Mersen offers the lowest cost, safest and most reliable surge protection products on the market. Their TPMOVs cover every nearly voltage need within your facility.

To see the full line of products, descriptions and features, you can download the PDF HERE.

While many people are familiar with the damage that a lightning strike can inflict, fewer people are knowledgeable about the dangers of indirect lighting strikes. In this video from Mersen, you’ll learn how their Surge-Trap SPDs can help protect you.

Are you new to surge protection or interested in learning more? Mersen offers education and collaborative product training annually with hands-on experience to learn more about their products. For more information, contact your French Gerleman Account Manager today.