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S&C Fault Tamer combines the functionality of a conventional fuse cutout and a backup current-limiting fuse in one powerful, easy-to-install package for the protection of new or existing overhead pole-top transformers through 25 kV. Fault Tamer addresses the critical issues facing protection engineers today. 

Fault Tamer is manufactured in accordance with a quality system certified to ISO9001:2000.

Fault Tamer provides these features and benefits over traditional fuse cutouts, or cutouts used in combination with backup current-limiting fuses.

Improved Transformer Protection

  • Ideally suited for protecting single- or three-phase transformers through
    • 100 kVA single-phase at 15 kV
    • 167 kVA single-phase at 25 kV
  • Excellent continuous, hot-load pickup, and cold-load pickup capabilities.
  • High surge withstand capability. Allows arrester to be mounted on transformer tank without increasing the chance of nuisance operations due to lightning.

Energy Limitation

  • Minimizes equipment damage
    • Reduces chances of catastrophic transformer failure from internal high-current faults.
    • Minimizes bushing and tank damage due to external primary faults.
  • Improves service continuity
    • Provides complete coordination with upstream lateral fuses.
    • Provides complete coordination with substation instantaneous relay settings.
  • Enhances power quality
    • Minimizes voltage dips that can cause sensitive electronic equipment to shut down.

Operational Characteristics

  • Dropout action.
  • No parts expelled during circuit interruption.
  • Complies with Australian Spark Production Standard AS 1033.1-1990. Ideal for installation in areas prone to grass fires.

Handling Characteristics

(On mobile, swipe left for remaining ratings information.)

50/60-Hz Ratings
Voltage, kVAmperes, RMS
System Class,
System MaximumBILCont.Interr., Sym.
60 Hz50 Hz
15 (12) 15 8.7 15 8.7 110 20 12 000
15 (12) 15 8.7 15 8.7 125 20 12 000
25 (24) 29 16.8 26 15.1 125 20 12 000
25 (24) 29 16.8 26 15.1 150 20 12 000
25 (24) 29 16.8 26 15.1 150 20 12 000
22/38 (20.8/36) 22 20.8 150 20 12 000

♠ Also applies to phase-to-phase applications. Applications involving single-phase transformers connected phase-to-phase, as well as three-phase applications require the use of a Fault Tamer in each lead.

Fault Interruption — How It Works

Fault Tamer Construction Features

On low magnitude faults, just the inexpensive fuse cartridge operates — similar to a conventional fuse cutout. Fault Tamer drops open, providing visual indication that it has operated.

On high-magnitude faults, both the fuse cartridge and the backup limiter operate. The fusible element in the limiter melts in multiple locations, creating myriad series arcs that promote an initial rapid increase in arc voltage. The increased arc voltage efficiently limits current to a small fraction of the prospective peak current. Fault current is driven to zero in a controlled fashion, as the fusible element burns back and arc energy is absorbed by the surrounding sand.

98021-D, 15 kV, 110 kV BIL


98072-D, 15 kV, 125 kV BIL


98022-D, 25 kV, 125 kV BIL

98052-D, 25 kV, 150 kV BIL

98053-D, 25 kV, 150 kV BIL

15 through 38 kV System Voltages
Curve TypeAmpere RatingsFuse TypeTCC NumberPDFExcel
Minimum Melting 3, 5, 7, 10, 15, 20 Fault Tamer TCC Number 450-8 PDF EXCEL
Total Clearing 3, 5, 7, 10, 15, 20 Fault Tamer TCC Number 450-8-3 PDF EXCEL
S&C Standard Speed (12 through 22 kV System Voltages)
Curve TypeAmpere RatingsFuse TypeTCC NumberPDFExcel
Minimum Melting 1, 2, 3, 5, 7, 10, 15, 20 Fault Tamer TCC Number 123-8 PDF EXCEL
Total Clearing 1, 2, 3, 5, 7, 10, 15, 20 Fault Tamer TCC Number 123-8-3 PDF EXCEL

A new version of the Coordinaide protection and coordination assistant software is now available for use. Key new features include:

  • Download a device’s curve data-points in a .CSV file format.
  • A new notification for “Transformer (Damage Curve)” device indicates how other device TCC curves are affected.
  • Curve selections were updated for the S&C TripSaver® II Cutout-Mounted Recloser:
    • Added NE and NK Speed under “Definite Time and Fuse Link” selection
    • Added a 140-A trip-coil rating for McGraw Type L, V4L, and 4E devices
    • Added “S&C A*” fast curves for McGraw Type 4E, 4H, L and V4L devices
  • A new Provide Feedback feature was added to submit feedback right from the application.
  • An updated User Guide now includes revision history.
Click the link below to access the new version of the Coordinaide protection and coordination assistant software today!

The Coordinaide protection and coordination assistant software lets you quickly and easily select the optimal protective device (e.g., fuses, TripSaver II Cutout-Mounted Reclosers, Vista® Underground Distribution Switchgear, or IntelliRupter® PulseCloser® Fault Interrupters) to:

  • Protect transformers against damaging overcurrents and coordinate with primary- and secondary-side protective devices.  See how S&C's novel Transformer Protection Index (TPI) can be used to determine if the primary fuse will protect against certain types of secondary-side faults, including arcing phase-to-ground secondary-side faults.
  • Protect capacitor units against case rupture.
  • Protect underground cables from insulation damage due to excessive temperatures.
  • Protect overhead conductors from damage due to annealing.
  • Confirm the proper operation of protective devices against incident-arc energy curves for various Personal Protective Equipment (PPE) levels.
  • Selectively coordinate two or more devices in series to minimize service interruptions.

Launch Coordinaide