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S&C Cypoxy® Insulators 4.8 kv through 34.5 kvIndoor and Outdoor DistributionNew Publication ©1988PHOTO SHEET 911-700Page 1 of 7October 31, 1988S&C Cypoxy® Insulators 4.8 kv through 34.5 kvIndoor and Outdoor DistributionIntroductionPorcelain insulators traditionally have been the mostwidely applied insulators in electrical transmission anddistribution systems. Although porcelain has served wellin that capacity, it has several drawbacks which includebrittleness, low impact strength, relatively high weight,and substantial limitations in manufacturing flexibility.In recent times, light-weight “non-porcelain” moldedepoxy resins have gained increasingly wide usage inapplications formerly provided with porcelain insulators.The first application of molded epoxy resins forelectrical insulation dates back to the 1950’s when thisnew class of organic material was used in themanufacture of indoor switch and bus insulators. Thisfirst generation of organic insulator proved to be wellsuited for indoor applications, and clearly demonstratedthe design and manufacturing versatility inherent tomolded epoxy resins. However, outdoor usage of theseinsulators indicated a sensitivity to ultraviolet radiationin sunlight, as well as susceptibility to tracking incontaminated environments. As a consequence, theperformance of the early epoxy resins in outdoorapplications temporarily diminished the appeal of suchinsulators for outdoor use, and delayed the broadcommercial acceptance of another improved class ofepoxy resin that was being developed in the early 1960’s.The newer materials developed in the early 1960’swere cycloaliphatic epoxy resins. Cycloaliphatic epoxyresins are organic compounds reflecting a ring-likemolecular structure; hence, the term “cyclo” aliphatic.The cycloaliphatic epoxies (of which there are a numberof different formulations) are comprised of saturatedmolecules that are inherently stable in the presence ofagents that caused poor performance in the first-generation of “unsaturated” epoxy resins appliedoutdoors. The cycloaliphatic epoxy resins developed inthe 1960’s not only provide the advantages of lighterweight and superior manufacturing flexibility inherentto the earlier epoxy materials, but also improvedresistance to weathering as now substantiated by moreFigure 1. Panorama of S&C Cypoxy products.911-700 PHOTO SHEETPage 2 of 7October 31, 1988than twenty years’ successful performance in boand outdoor environments.S&C Cypoxy InsulatorsS&C’s Cypoxy insulators incorporate a uniquelyformulated cycloaliphatic epoxy resin system etailored to provide the electrical and mechstrength characteristics detailed in industry sfor porcelain insulators, as well as unsurperformance in hostile outdoor environments.S&C’s experience with Cypoxy spans more15 years, and dates back to 1973 with the intof specialized housings, pushrods, and strutswith distribution switches (see Figure 1). Theto mold Cypoxy into intricate shapes with lightand high strength has made Cypoxy an indiscomponent of S&C’s products. The light weighinertia) and high strength of Cypoxy compmoreover, has made it possible to develop compasaving switch designs not possible with convPorcelainInsulatorMetalend capCypoxyInsulatoraled, thets waseloped forroducts., by 1978, porcelains. use forods ford withtors to thiss are incal andonments.sulatorsdevelopedechanical-Standardation post designedlators, androductsproducts pages 6using aIn thishichhydratedtrolledprecision-tively lowintricateorcelain)rs can beor a given 2). The typicallyal “cast-of metals provide porcelaincaps. Andors is theically onnsulators, charac-lues, plus CypoxyWt: 40 Ibs Wt: 21 Ibs.Figure 2. Comparison of Cypoxy Insulator to conventionporcelain Insulator (34.5 kv, 200 kv-BIL).th indoorspeciallyanical-tandardspassed thanroduction for use ability weightpensablet (lowonents,ct space-entionalporcelain components.As S&c’s Cypoxy-production facilities expandspecialized offering of Cypoxy componenbroadened to include apparatus insulators devuse with S&C’s distribution switch and fuse pThe success of these insulators was such thatCypoxy insulators had completely supplantedinsulators for all S&C indoor switches and fuseCypoxy insulators have also been in wideoutdoor products, with usage of Cypoxy pushrAlduti-Rupter® Switches dating back to 1976, anthe introduction of outdoor Cypoxy insulaLoadbuster Disconnects® dating back to 1980. Attime, many thousands of Cypoxy insulatoroutdoor service with outstanding electrimechanical performance in all types of envirMost recently, a line of station post Cypoxy inin voltages of 15 kv, 25 kv, and 34.5 kv has been which meets or exceeds the electrical and mstrength requirements established in ANSI C29.9 (1983) for porcelain standard-strength stinsulators. Cypoxy station post insulators areas replacements for porcelain station post insuare now available on a wide variety of S&C prated through 34.5 kv. A panorama of S&C available with Cypoxy insulators is included onand 7.Mechanical CharacteristicsS&C Cypoxy insulators are manufactured process called pressure-gelation molding. process,cycloaliphatic epoxy compound-wincludes a portion of silica and highly refined alumina-is introduced under carefully conconditions of pressure and temperature to machined steel molds. The pressure and relaviscosity of the mixture permit formation of contours that are not possible with fired-clay (pinsulators. As a consequence, Cypoxy insulatomanufactured with substantially more sheds fheight than porcelain insulators (see Figureincreased number of sheds contributes to thegreater leakage distance of Cypoxy insulators.Cypoxy insulators, in addition, include integrin-place” threaded aluminum inserts in lieu end caps. As a consequence, Cypoxy insulatorsubstantially greater dry arcing distance thaninsulators which include cemented steel end another important advantage of Cypoxy insulatlight-weight design. Cypoxy insulators are typthe order of one-half the weight of porcelain ibut with comparable mechanical-strengthteristics. Leakage distance and dry arcing vaweight and mechanical-strength values forPHOTO SHEET 911-700S&C Cypoxy® Insulators 4.8 kv through 34.5 kvIndoor and Outdoor Distributioninsulators are published in S&C Data Sheet 911-300.S&C Cypoxy insulators are homogeneous, and neitherrequire nor include a surface glaze. A glaze providesposfetaaossoicsa ttemperature arc decomposes minute amounts ofhydrated alumina used in the Cypoxy material-therebyliberating water of hydration as steam that scours thesurface of the insulator in the path of the arc. Asbjectedarc forl damagensulatorn cleaned. The path isetal arce powerr powerrc cleanupxympletely will notronment.ce of aears of climate,s visualnce intory andanical-nmentaloutdoortantiatedCypoxyypoxyually notical testCypoxyvironmentg tests,sts at an at thatatingctors to periods.o furthertors havetal test forclimateadditional strength for porcelain insulators butit be damaged, can result in substantial loss of mstrength. Loss of glaze can also provide sideposition of contaminants on the surface of a insulator. Cypoxy insulators, being homogenenot susceptible to surface “crazing” that iassociated with glazed materials. And should ainsulator be chipped due to rough handling or vathe exposed surface will provide the same percharacteristics of the original surface.Electrical CharacteristicsIn addition to the light weight and compact dCypoxy insulators, these insulators are also nonself-scouring, and nonweathering.Nontracking performance of an insulator ensuresunder the stress of applied voltage, the insulnot develop conductive tracks that promote current and eventual loss of dielectric strengtformulations of organic epoxy resins are suscematerial decomposition under voltage stress band arcing that can result in conductive carbtracking across the insulator surface. Over timtracks may branch and lengthen to a poicompromises the dielectric integrity of the insuS&C Cypoxy insulators are nontracking becaupyrolysis of Cypoxy in the event of minute lowarcing produces gaseous by-products such adioxide and water vapor that leave the surfaceresidue-free. Without track development, lcurrent is kept to a minimum level that cannthe performance of the insulator. Cycloaliphatiresins have outstanding resistance to trackS&C’s unique formulation of cycloaliphatic epobeen specially tailored to provide the traperformance of Cypoxy insulators. As shown in Fithere is no evidence of tracking on a 15-kv classinsulator continuously energized at nearly 1½ times ratingover a ten-year period.Self-scouring performance is another characteriCypoxy insulators that is directly attributableproperties of the specially formulated Cypoxy mSelf-scouring performance ensures that the insulator will “clean” itself and thereby maintBIL insulation after interruption of an externalarc-due perhaps to lightning or bridging by anSelf-scouring performance is achieved because 911-700 PHOTO SHEETPage 4 of 7October 31, 1988, shouldechanicaltes fororcelainus, are often Cypoxyndalism,ormancesign ofracking, that,tor willleakageh. Someptible tond dry-naceouse, suchnt thatlator.e local-power carbon virtuallyeakaget affectc epoxyng, andxy hask-freegure 3, Cypoxytic of to theaterial.Cypoxyin full poweranimal.he high-illustrated in Figure 4, a Cypoxy insulator suto a 10,000-ampere symmetrical power approximately 10 cycles exhibits no structurafollowing the arcing event. Moreover, the imaterial in the direct path of the arc has beeby the self-scouring action of the Cypoxydiscoloration in the border regions of the arcdue to drift of vaporization products of the mterminals and “flash wire” used to initiate tharc. A porcelain insulator subjected to a similaarc may suffer glaze damage and require post-aor replacement.The nonweathering characteristics of S&C Cypoinsulators ensure that the insulators are coresistant to ultraviolet radiation, and that theyreact with water or contaminants in the enviAs shown in Figure 3, the unweathered surfa15-kv class Cypoxy insulator unit with 10 ycontinuous outdoor exposure in a midwesternand continuously energized at 21 kv provideevidence of Cypoxy’s outstanding performaoutdoor environments.Laboratory and Field Test ExperienceS&C Cypoxy insulators are exhaustively laborafield tested to meet electrical and mechperformance ratings under all types of enviroconditions. Ongoing test procedures in an seacoast test facility in California have subssuperior resistance to weathering of S&C’s insulators. After 10 years’ exposure, S&C Cinsulators are in excellent condition, with virtsurface erosion or evidence of tracking. Idenresults have been observed with regard to insulators subjected to a severe midwestern enover a ten-year period.In addition to “real time” outdoor weatherinS&C has conducted accelerated-weathering teoutdoor desert test facility in Arizona. Testingfacility includes an EMMAQUA test incorporpower-driven equatorially mounted solar reflefocus sunlight on test samples over extendedThe test also includes a periodic water spray tenhance the severity of the test. Cypoxy insulabeen subjected to this accelerated environmenthe equivalent of 40 years’ exposure in a equivalent to that of Atlanta, Georgia. For more northernregions, the equivalent exposure is even longer. And,in terms of actual commercial experience for outdoorapplications, S&C Cypoxy insulators now reflect morethan a decade of successful application in thousandsof installations worldwide.Cypoxy insulators,in addition to exhaustiveenvironmental testing, have been rigorously tested toconfirm electrical ratings including impulse withstand(BIL) and low-frequency withstand (1 minute dry and10 seconds wet). Extensive mechanical testing is alsoperformed on a continuing basis to confirm cantilever-strength, tensile-strength, and compression-strengthratings of Cypoxy insulators. Thermal cycling tests,moreover, are conducted to confirm the ability of theinsulator to withstand repetitive heating to ±120°Ffollowed by cooling to –40°F.In addition to testing of completed units, rigorousincoming inspections including infrared spectroscopyand liquid chromatography are employed to ensure thatcomponent materials used in the Cypoxy formulationmeet the applicable S&C specifications.In the 15 years S&C has been engaged in productionof Cypoxy insulators more that 1½ million Cypoxycomponents have been shipped with S&C products, withunsurpassed performance in indoor and outdoorenvironments. Products offered with Cypoxy insulatorsare pictured on the following page.rrFigure 3. S&C 15-kv class Cypoxy Insulator, continuouslyenergized at 21 kv, with approximately 10 years’ exposuto outdoor environment.eFigure 4. Cypoxy insulator following 10,000-ampere powearc.PHOTO SHEET 911-700Page 5 of 7October 31, 1988S&C Cypoxy® Insulators 4.8 kv through 34.5 kvIndoor and Outdoor DistributionProducts Available withS&C Cypoxy InsulatorsCypoxy insulators are available in ratings of 4.8 kvthrough 34.5 kv and are offered with a broad selectionof S&C products including: Resistored Power Fuses;Indoor and Outdoor SM Power Fuses; Station StyleSMD-20 Power Fuses; Station Style XS Cutouts; Indoorand Outdoor Distribution Switches including Mini-Rupter® Switches, Alduti-Rupter Switches, and Omni-Rupter® Switches; Loadbuster Disconnects; Convert-ible Disconnects; Regulator Bypass Switches; andRecloser Bypass Disconnects. Following is a pictorialsampling of S&C products-both indoor and outdoor-that are available with Cypoxy insulators.For additional information concerning Cypoxyinsulators or products furnished with Cypoxy insulators,consult your nearest S&C Sales Office.911-700 PHOTO SHEETPage 6 of 7October 31, 1988e-lainstancel capsnga-up toithout evenThe Cypoxy Advantage.. .Light weight . . .typically on the order of onhalf the weight of comparable porceinsulatorsGreater dry arcing (strike) distance . . . end-cap-free design provides greater strike direlative to porcelain insulators with metaNontracking, self-scouring, nonweatheriperformance . . .provides dependable insultion in all types of environments; stands high-power arcs without damage and wneed for post-arc “cleanup.” Won’t track,in contaminated environments . . . resistant toultraviolet radiationSuperior toughness . . . greater tolerance tophysical impact; will not shatter due to thermalshockSuperior strength . . . meets or exceedsmechanical-strength values for comparableporcelain insulatorsCompact insulator designs . . . made possibleby manufacturing versatility inherent to moldedepoxy resinsEconomical . . . products with Cypoxyinsulators cost less, and save money-bothinitially and down the road-relative to productswith porcelain insulatorsPHOTO SHEET 911-700Page 7 of 7October 31, 1988