Surge Protection

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Alltec Protection Pyramid Surveys

A Three Part Series

Part II – Surge Protection

If you missed Part I – “Grounding & Bonding”, you can find it here.

This second installment of a three part series relates to the middle tier of the Protection Pyramid- Surge Protection, which is additionally required to:

  • Protect critical facilities, equipment, records, and assets.
  • Provide a safe working environment for personnel.
  • Reduce the risk of downtime and lost revenue.
  • Reduce vulnerability of interdependent critical infrastructures, and build a disaster resilient enterprise
  • Minimize liability and maintain a competitive posture.

Grounding and Bonding alone are not sufficient to adequately protect a facility. Transient voltage surge suppression (TVSS) techniques, using appropriate Surge Protection Devices (SPD), should also be incorporated and fully integrated into the facility’s inspection and maintenance program.

Electrical transients are defined as momentary bursts of energy that are induced upon power, data, or communication lines. They are characterized by extremely high voltages that can drive tremendous amounts of current into an electrical circuit for a few millionths, up to a few thousandths, of a second. Large transients on the power system originating outside of a facility are best initially diverted at the service entrance of a facility. Transients generated within the premises can best be diverted by SPDs located close to the internal source of the transients, or close to the electronic load equipment if this is not possible. Best results are obtained if both locations are protected.

Lightning / Surge Protection
Utility Grid Switching / Surge Protection
Internal Loads / Surge Protection

Standards for the “Installation Requirements for Lightning Protection”, NFPA 780, Section 4.20, and UL 96A, Section 13, detail the requirements for surge protection associated with lightning protection systems, and IEEE 1100 – 8.6 states: Surge activity is often assumed to be an outside engendered anomaly. Lightning induced electrical energy bursts, for example, typically come to mind as the primary source of surge activity. However, while lightning induced surges represent the most formidable transient related equipment menace, most surges originate from internal sources within a facility.

Studies have verified that approximately 80% of transient activity at a given facility is internally generated. Any time an inductive load, whether it is a vacuum cleaner or a heavy duty motor, is either powered on or off – it generates a low magnitude surge impulse that propagates back through the electrical distribution. While internally generated transient activity can weaken equipment over time, the threat posed from lightning activity is particularly disconcerting due to its capability of delivering vast amounts of energy into unsuspecting electronic equipment loads.

As with any survey, the best way to start is with a site evaluation:

  • Collect information on types of damages experienced or anticipated by the facility, and create a prioritized outline of survey requirements.
  • Study existing site plan drawings, site electrical panel layouts, one-line electrical and riser diagrams
  • Determine critical load paths and physical panel and equipment locations

After developing an understanding of the facility and its needs, and creating a site specific inspection plan, typical actions include:

  • Note critical loads on the electrical distribution system
  • Review upstream to note location and specification of each distribution node.
  • Note specifications and location of any surge protection device installed.
  • List compliance of transient surge protection system with IEEE std. C62.72 and IEEE std. 1100.
  • Categorize each distribution node as per IEEE Std. C62.41 and select appropriate category of surge protection devices.

In order to determine the proper surge protection devices to be installed, the following information should be obtained, for reference during and after the survey:

  • Electrical One-Line Diagram/Riser Diagram
  • AC Power Panel/Critical Load Schedule
  • Voltage Configuration, i.e., Delta, Wye, Wire Color System
  • Data/Telecom Distribution Details, if required
  • Frequency Range
  • Connector Type/Gender Type

Depending upon the complexity of the power distribution system, as well as the facility grounding system, it is quite often very efficient and effective to inspect and test both at the same time. Start at the main utility power entrance, the main distribution panel and follow the critical load paths. A typical example of a simple system and the proper location of surge protection devices is shown in the riser diagram below.

Typical Riser Diagram

Drawing mark-ups, notes and photographs taken during the inspection are valuable in creating an inspection and recommendations report. During the inspection, field notes should be gathered and organized, recording:

  • Spare breakers for any required SPDs.
  • Voltage configuration for each panel in the critical load path.
  • Wire distances between panels, as well as between panels and equipment.
  • Available space for proper installation of recommended SPD
  • Confirm that the breaker/disconnect is in the ON position and that Surge Protection Devices appear to be untampered with.
  • Confirm that UL 1449 SPDs have 3rd Edition labeling
  • If observable, ensure that SPD units are properly connected and that all connections are secure. All wire paths should be as short and direct as possible.
  • Surge devices are operational/undamaged (all phase indicator lights are functioning).
  • If SPD unit appears non-operational (one or more phase indicator lights are OFF), make note of downstream critical equipment for evaluation of possible damage.
Surge Protection Switch Box Open
Surge Protection Switch Box Close

An on-site survey and evaluation should yield a Survey Report with supporting documentation, containing observations and site photographs as needed, and specifically:

  • List compliance of existing Surge Suppression Devices and recommend any upgrades required to cover noncompliance.

One of the most important investments a company makes is in sensitive electronic equipment. As this equipment becomes more sophisticated and electrically susceptible, the need for a properly sized and coordinated surge protection becomes more crucial. Examples, such as cellular, radio and television broadcasting sites, computer facilities, power substations, communication centers, medical facilities and industrial plants all share the common need for the design, implementation and inspection/maintenance of high quality surge protection systems.

Below is an application map showing expected SPD locations at a typical facility:

Surge Protection Application Map

If you want to see what ALLTEC can do for you, be sure to visit . For more information please contact ALLTEC at either 1-828-646-9290 or

Rev. 20160829

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