Fault Tamer ® Fuse Limiters

The New Generation of Protection for Pole-Top Transformers—S&C’s Fault Tamer Fuse Limiter combines a series fuse and backup limiter in one powerful package which can be easily incorporated in new or existing installations of 14.4-kV, 25-kV, and 34.5-kV overhead pole-top transformers. Fault Tamer provides short-circuit protection to the system, limits let-through current to a level which will minimize catastrophic transformer failures due to high-magnitude internal faults, and also minimizes damage from high-magnitude external faults such as bushing flashovers. Fault Tamer offers major benefits over conventional fuse cutouts, including cutouts appendaged with bolt-on backup current-limiting fuses.

Improved Service Continuity
Conventional fuse cutouts have limitations that can compromise service continuity. For example, close to substations—where fault currents can be high—complete coordination frequently is not possible between the fuse link protecting a pole-top transformer and the upstream lateral fuse link. As a result, a large-magnitude fault, such as a wildlife-induced flashover of a transformer bushing, can not only cause the transformer fuse link to operate but the lateral fuse link as well . . . exposing all customers on the lateral to an extended outage. Fault Tamer eliminates this problem because it coordinates with lateral fuse links over the full range of fault currents.
And, unlike conventional cutouts, Fault Tamer’s current-limiting action provides clearing characteristics which coordinate with the instantaneous setting of the substation circuit breaker, thus eliminating unnecessary momentary interruptions for transformer faults exceeding the breaker’s instantaneous setting.

Enhanced Power Quality
High-magnitude faults near a substation can suppress the voltage on the substation bus, as well as on feeders emanating from the substation. Fault Tamer’s current-limiting action clears high-magnitude transformer faults before voltage dips can damage or shut down sensitive electronic equipment served by adjacent feeders.

Maximum Surge Protection
Voltage surges are a major cause of overhead transformer failure. Maximum protection from overvoltages can be achieved by mounting the surge arrester on the transformer tank, thus shortening the lead from the arrester to the transformer winding and to ground. But with the surge arrester connected to the load side of a conventional cutout, the fuse link is more susceptible to nuisance operation from lightning strikes. Fault Tamer’s high inrush withstand capability eliminates this problem . . . arresters can be tank-mounted without concern for nuisance fuse operations.

Impossible to Mismatch Series Fuse and Limiter
In cutouts with bolt-on backup current-limiting fuses, it’s possible to inadvertently apply the wrong size fuse link— thus jeopardizing the integrity of your coordination plan. But the clearing characteristics of Fault Tamer’s fuse cartridge are matched to that of the backup limiter so coordination is assured.

Simpler Handling—Re-fusing a bolted-in backup current-limiting fuse means climbing the pole, or using a bucket truck, to remove the fuse with a wrench—a time-consuming procedure that requires wearing gloves and other safety garb.

But re-fusing Fault Tamer is quick and easy. Since Fault Tamer’s combination fuse tube and backup limiter drops open after a fault-clearing operation, it can be removed from the mounting from the ground using an extendostick. The process is made even easier by use of S&C’s TalonTM Fuse Handling Fitting.

Retrofit Existing Installations
Fault Tamer is designed to fit into all vintages of S&C Type XS Fuse Cutouts. You can upgrade to Fault Tamer’s superior current-limiting protection at minimal cost.

Heightened Safety—Fault Tamer’s backup limiter features internal exhaust control which prevents fuse cartridge parts from being expelled during a fault-clearing operation. In contrast, conventional fuse cutouts—even fuse cutouts with bolted-on backup current-limiting fuses—can violently expel fuse link parts during operation . . . a potential exhaust hazard to operating personnel.
And Fault Tamer provides an extremely significant reduction in fire hazard as compared to conventional fuse cutouts. Fault Tamer complies with Spark Production Class A in Australian Standard AS 1033.1-1990, which requires that no sparks may be produced during a fault-clearing operation.

Mates Perfectly with Loadbuster® Tool—Using S&C’s portable loadbreak tool, live switching can be done at the point that minimizes the length of planned outages and the number of customers affected.