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    Phase Identification

AP30 PhaseTrakker® Atomic

Underground/Indoor/Outdoor Phase Identification System

Available for the United States & Canada


    • Phase underground or indoor or overhead on 120V to 500kV circuits
    • Test without de-energizing lines
    • Balance loads to minimize system loss
    • Reduce safety hazards and damage to equipment
    • Identify and mark correct phasing for system mapping
    • Ensure substations’ connections are phase correct
    • Export results to GIS without de-energizing power lines (120V to 500kV).


    Utilizing the same operating platform as the original AP30, the Atomic system incorporates cesium clock technology into its GPS timing circuitry, enabling utilities to identify circuit phase in deep vaults or indoor panels where Phase ID is typically unavailable.

    • AP30 LowVolt Sensor
      AP30 LowVolt Sensor
      The handheld AP30 LowVolt Sensor (AP30-LVS) is used in place of the AP30 Hotstick Unit to phase on voltages between 0.5 V and 300 V. The LowVolt Sensor is sold separately from the AP30 Field Unit.
    • Non-Contact Sensor
      Non-Contact Sensor
      This handheld sensor is used in place of the AP30 Hotstick Unit when physical contact with the energized source is less convenient or not practical. The sensor is not operable in substations because of the multiple strong E-fields present. New AP30 Field Units can be ordered to include the Non-Contact Sensor, and it can also be purchased separately.
    • Remote Antenna for Field Unit
      Remote Antenna for Field Unit
      This dual antenna attaches to the antenna ports in the storage compartment of the Field Unit, and takes the place of the Field Unit’s built-in antenna. This allows the Field Unit to operate in vaults or other locations where GPS signals are unavailable. The remote antenna is mounted on a handy wind-up reel with 50 feet of cable.
    • Cellular Amplifier Kit for Field Unit
      Cellular Amplifier Kit for Field Unit
      This kit amplifies network signals up to 6 times, and is recommended when immediate phase identification is needed in areas of intermittent network reception. The kit comes with network signal amplifier, two antennas, rechargeable battery and battery charger.
    • Rain Cover for Field Unit
      Rain Cover for Field Unit
      This custom vinyl cover slips over the opened lid and protects the faceplate and storage compartment in rainy weather. A clear panel in the cover allows continued operation of the Field Unit touch screen.
    • Extension Cables for Reference Unit Antenna
      Extension cables for the Reference Unit’s dual antenna are available in a variety of lengths. Contact EDM to order.

  • The purchase of every PhaseTrakker field unit includes free access to regional base Reference Units located across the United States and Canada.

    Reference Units are available for companies that wish to purchase their own base units. For more information, contact your local product representative, or EDM.
    (800) 687-4196 | This email address is being protected from spambots. You need JavaScript enabled to view it.

    reference unit rack
    Phasetrakker AP30 reference unit portable
    Phasetrakker AP30 reference unit portable
  • Representatives
Pricing & Ordering

Sam Jack

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Diane Hurst

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PHASETRAKKER AP30 Product Overview


Why is accurate phase identification so important?
  • It’s common for underground cables to be mislabeled. This causes confusion during outages. Also, when two circuits need to be looped together, the labeling must be right. It’s inconvenient to de-energize a circuit to determine phasing. PhaseTrakker JR determines phasing on energized equipment.
  • Long over-head lines can easily have mislabeled or uncertain phasing. This can result in substation problems such as delays in construction.
  • When a utility wants to optimize load balance to reduce losses, it’s essential to know which phase is which, so loads can be transferred correctly.
  • If a protective relay or revenue meter is working incorrectly, it’s vital to know where the phasing got mixed up.
  • It’s common to have confused phasing through three-phase transformers. It’s important to determine the phasing to avoid trial-and-error transformer connections.
  • Besides the issues associated with load balance and system optimization, inaccurate phase labeling can result in equipment damage and injury of personnel.
Why not use “Phasing Sticks” instead?

A set of Phasing Sticks is really just a high-range voltmeter that will determine if two phases match or not. Phasing Sticks can determine if two like-labeled conductors are actually different phases, but PhaseTrakker JR is required to determine which one is labeled correctly.

Can PhaseTrakker JR determine phase rotation?

Yes. PhaseTrakker JR will display the phase angle of every voltage reading. This determines rotation.

Where can PhaseTrakker JR be used?

PhaseTrakker JR will determine the phase of any energized conductor with at least 120V and has been used up to 500kV.

  • Bare buswork as in substations
  • Bare conductors such as distribution or transmission lines
  • Taped buswork as used in switchgear
  • Test points on 200A cable elbows
  • Test points on 600A cable elbows
  • Insulated bolts on the back of 600A T-body elbows
  • Potential transformer secondaries. (It will work indoors as long as the Hotstick Unit is in sight of the Field Unit and the Field Unit is outside an open door.)
  • 120V household outlet
  • With the optional GPS/Cell antenna extension reel, the Field Unit can be taken into deep vaults or indoors to determine phasing.
What’s the maximum distance between the Reference and Field Unit?

Measurements have been routinely taken with a distance of 800 miles between the Reference and Field Units. At this distance it is common to get some seasonal power angle shift across the power grid, so it’s a good idea to verify occasionally on a known phase before checking unknown equipment.

This power angle shift should be insignificant at the more normal maximum distances, say in the 300 mile range.

What are the basics of how PhaseTrakker JR system works?

The Reference Unit takes a reading every second of the degrees to the next voltage sine wave zero crossing. When a Field Unit calls in, the Field Unit compares the local angle measurement to the cataloged value for that matching second. Since the GPS time is precisely the same at each location and since the phase “A” voltage is in phase at each location, the angle comparison determines how many degrees the Field Unit voltage is away from the Reference Unit, which then determines the phase identification as well.

What factors make PhaseTrakker JR a superior product in the marketplace?
  • PhaseTrakker JR provides instantaneous absolute phase and phase angle identification, anywhere on an overhead or underground transmission or distribution system, (where live contact is possible.)
  • With each purchase, the PhaseTrakker JR unit includes a free year of cellular service.
  • In areas where no cellular service is available, PhaseTrakker JR can still record up to 1000 phase readings over a period of 30 days, which can be retrieved when cell signal is re-acquired. The system is configured to allow transferring the phase data to a laptop for use with mapping systems and databases.
  • PhaseTrakker JR is portable, durable, and can be used independently from the work vehicle.
  • PhaseTrakker JR features an easy to read LCD screen, and all calibration functions can easily be performed via convenient touch-screen process. Phase readings can be instantly shifted to adjust for Delta-Wye transformers.
  • PhaseTrakker JR can be calibrated to communicate with 2 Reference units at different locations. As long as the Field Unit and Reference Unit are located on the same power grid, (regardless of distance,) phase identification can be achieved.

United States Representatives

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Canada Representatives

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EDM International, Inc. is headquartered in Fort Collins, Colorado and has offices in San Diego, California,
Phoenix, Arizona and
 staff in other locations in North America.

Copyright © 2023 EDM International, Inc. |  4001 Automation Way • Fort Collins, CO 80525 U.S.A. • 970-204-4001  |  This email address is being protected from spambots. You need JavaScript enabled to view it.
Design & Development, Full Circle Creative | Cover image: Erik Stensland, "Bierstadt Fire" - Rocky Mountain National Park - not far from EDM's Headquarters.