UNDER GR OUND K-4 | www.hubbell.com/burndy Underground Connectors and Accessories Overview by Type The MOLE™ and HYCRAB™ The most popular of the engineered connectors developed specifically for underground manholes and trasformer vaults are the MOLE™ and HYCRAB™ that provide for multiple connections at a single junction point of main, feeder, and service cables. Pre-insulated to eliminate extensive taping, these connectors are essentially bus bars with several cable outlets: mechanical installation of the MOLE™, and compression installation in the HYCRAB™. Limiters and Fuses To prevent “roasting” of cable insulation, resulting from fault current, BURNDY has developed cable limiters that are inserted in each secondary cable at all junction points. Network protector fuses have been designed to back up the protector breaker in teh event of a malfunction during a transformer or primary cable fault. By coordinating the time current characteristics of the fuse with those of the cable limiters, the possibility of limiter blowing on primary faults is eliminated, which in turn redcuces the fault finding task. Also, limiter, fuse, and cable insulation characteristics must be carefully coordinated to assure isolating a fault on the secondary before it can cause extensive damage or interrupt service in other sections of the secondary system. High Capacity Limiter 200,000 Amperes at 600 Volts The BURNDY® High Capacity Limiter is designed to economically protect electrical distribution systems from the destructive effect of high energy faults. The increasing number of 600 volt secondary network installations for industrial and commercial applications demand a cable limiter that can safely interrupt 200,000 amperes (symmetrical available) and one that will also completely coordinate with the higher voltage network protector fuses. Available fault currents as high as 200,000 amperes rms at 600 volts across the fusible elements have been interrupted during tests on the BURNDY® High Capacity Limiter. The power factor during these tests was less than 15%, thereby imposing the most difficult clearing conditions. No external disturbance is experienced upon clearing fault currents from the “float” value to 200,000 amperes. The quartz filler absorbs the intense energy generated by interrupting the fault current. The quartz fuses into tobular fulgurites, with a high dielectric strength, and forms an insulating barrier between the melted link sections. This action prevents restrike of the internal arc. The rugged glass melamine housing provides a vessel that completely contains the developed energy. This carefully developed time-current characteristcs and rigid manufacturing tolerances assure proper coordination with the network protector fuses and the insulation damage characteristics of 4/0, 250, 350, 500, and 750 kcmil cable. The High Capacity Limiter is available in four variations to accommodate a variety of installation practices. The Type HYS has cable sockets at both ends, which allow for indenting to the cable ends with a hydraulic BURNDY® HYPRESS™. The HYAO type has an offset lug on one end which permits back-to-back mounting on bus bar. For those installations where the BURNDY® MOLE™ product is used for manhole junctions or transformer vault buses, the Type HYM permits a replaceable connection of the limiter directly to the MOLE outlet at one end and a compression cable connection at the other. Modern electrical distribution systems require low cost protection to safeguard costly equipment and quickly isolate faults, so that the undamaged portions of the system may function normally. BURNDY® High Capacity Limiters assure positive, economical protection when installed in properly designed systems. Compression Connectors BURNDY® HYDENT™ compression type connectors, and installation tools, have been designed for splicing and terminating copper as well as aluminum underground cables, in both primary and secondary circuits. BURNDY tools and dies are custom designed to produce sound electrical, and mechanical joints on BURNDY connectors. The use of the BURNDY® Engineered System with matched tools, connectors and dies, assures optimum results. Residential Underground The trend toward improvement in neighborhood appearances, and the elimination of storm outages, tree trimming, etc. has created the need for residential underground distribution. To meet these needs, BURNDY offers: Mechanical type pre-insulated multi- conductor terminal connectors for submersible transformer locations; and compact multiconductor connectors for above ground transformer and enclosures. For service taps, BURNDY offers: Pre- insulated multi-conductor compression and mechanical connectors; and a range taking compression connector for below grade service. Power pedestals for direct burial, above ground application, and conduit systems are offered. Residential Underground Fuse Block assembly with replaceable fuse for each service cable is also available.
