NOTE This specification covers the selection, procurement, installation, splicing, termination, and field acceptance testing of shielded medium-voltage power cable rated 5 kV through 35 kV for primary distribution systems in commercial, institutional, and industrial facilities. (1.1)

NOTE The scope encompasses single-conductor and multi-conductor extruded-dielectric cable insulated with ethylene-propylene rubber (EPR, Type MV-105) or cross-linked polyethylene (XLPE, Type MV-90), in voltage classes of 5 kV, 15 kV, 25 kV, and 35 kV, installed in concrete-encased duct bank, conduit, cable tray, underground vaults, or by direct burial. (1.2)

NOTE Primary feeders in scope run from the utility point of delivery or facility substation to medium-voltage switchgear, unit substations, motor control centers, and transformer primaries, on campus distribution loops and industrial plant primary systems where power is distributed above 2,000 V. (1.3)

NOTE A medium-voltage cable failure interrupts the entire downstream distribution served by the feeder, and the dominant failure modes — termination and splice workmanship, shield discontinuity, and damage during pulling — are introduced during installation rather than manufacture. The requirements of this standard reflect that consequence and concentrate on the field operations that determine in-service reliability. (1.4)

NOTE This standard is inseparable from Underground Ductbank, which governs the duct bank, conduit, and manhole systems through which most cable in scope is pulled; the cable terminates into equipment governed by Medium Voltage Switchgear and Secondary Unit Substations; and coordination with the low-voltage systems of Conductors And Cables is required where MV feeders supply transformers stepping down to building distribution. (1.5)

NOTE This standard does not cover low-voltage cable rated 600 V and below, the raceway and civil duct-bank systems that house MV cable, the switchgear and interrupter equipment fed by the cable, capacitor-bank feeders, high-voltage transmission cable above 46 kV, or bare overhead and aerial covered conductors. (1.6)

NOTE The Contractor shall submit the following action submittals for review before fabrication or procurement: (3.1.1)

NOTE The Contractor shall submit the following informational submittals: (3.2.1)

NOTE The Contractor shall submit the following closeout submittals before final acceptance: (3.3.1)

NOTE Splicing and terminating are the operations most determinative of in-service reliability, because removing the semiconducting shield and reconstructing the electrical-stress geometry by hand at every joint and termination introduces stress concentrations that the factory dielectric never sees. This standard therefore qualifies the technician, not only the materials. (4.2)

NOTE The voltage class of the cable shall match the system nominal operating voltage; a 13.8 kV system requires 15 kV class cable, not 5 kV class cable. (5.1)

NOTE The most common error in medium-voltage cable specification is selecting a voltage class below the system operating voltage. Voltage class denotes the system band the cable insulation geometry is designed for, not a withstand margin. The 15 kV class is by far the most common for US campus, healthcare, university, and large commercial primary distribution because the prevalent 13.2 kV and 13.8 kV systems fall within it. (5.2)

NOTE Insulation level expresses how long the cable insulation must tolerate the phase-to-phase voltage appearing across an unfaulted phase during a ground fault, which depends on the system grounding and the protective relaying. The 100% level suits solidly grounded systems that clear a fault in one minute or less; 133% suits systems that clear within one hour or are impedance/resistance grounded; 173% suits ungrounded systems or those that operate faulted indefinitely. (5.3)

NOTE Most facility systems are not solidly grounded with sub-minute fault clearing, so the default insulation level for the typical facility application is 133%. Specifying 100% level on a system that does not meet its grounding and clearing conditions under-insulates the cable for the fault duty it will actually see. (5.4)

NOTE The installation method governs the ampacity derating, the required jacket and armor, and the mechanical protection the cable receives, so it shall be established before conductor size is finalized. (5.5)

NOTE Insulation type is the central material choice. EPR (Type MV-105) operates at 105 °C and XLPE (Type MV-90) at 90 °C; the 15 °C higher operating temperature of EPR yields a meaningful ampacity advantage, and EPR is more flexible and easier to terminate in the confined manholes and switchgear cubicles typical of facility work. EPR is therefore the 80% default for institutional and facility primary feeders, while XLPE remains a valid lower-cost choice for straightforward duct-bank runs. (6.1)

NOTE Insulation thickness is fixed by the ICEA S-93-639 / NEMA WC74 tables for the selected voltage class and insulation level and shall never be specified below the standard minimum. For 15 kV at 133% level, the minimum is 175 mils for both EPR and XLPE; the specifier shall confirm the value for the actual class and level against the current edition. (6.2)

NOTE Conductor material for facility primary feeders is standardly copper, which is the default; aluminum is a cost-driven alternative that, for equal ampacity, requires a larger conductor and correspondingly larger conduit. (6.3)

NOTE Conductor stranding shall comply with ASTM B8 for concentric round or ASTM B496 for compact round; compact round is commonly specified for medium-voltage cable to reduce overall diameter and improve the seal of pre-molded fittings. (6.4)

NOTE The metallic shield carries charging and fault return current and establishes the ground reference around the insulation. A helical copper tape shield is the standard construction for shielded feeders; concentric neutral construction is used where the system neutral must be continuously grounded along the entire run, as in some direct-buried distribution. The two are not interchangeable: they have different fault-current return capacity and different installation handling. (6.5)

NOTE Copper tape shield shall be a minimum of 5 mil thick applied helically; the overlap determines the fault-return path quality, with 12.5% being the minimum and 25% commonly specified for a more robust return path. (6.6)

NOTE Concentric neutral sizing shall be a full neutral for direct-buried runs; a one-third neutral is acceptable only for duct-bank runs where the available fault current is limited by system relay coordination. (6.7)

NOTE The jacket protects the shield and insulation from the installation environment and governs flame and smoke behavior inside buildings; the material shall be selected for the installation environment and any flame or low-smoke requirement. (6.8)

NOTE Cable configuration is single-conductor or multi-conductor. Single-conductor construction is the dominant choice at 15 kV and above and for most facility feeders; multi-conductor (3C or 3C with ground) is common at 5 kV for compact branch feeders in tighter routing. (6.10)

NOTE Conductor size shall be established from the NEC Table 310.60(C) series and IEEE 835 for the actual installation configuration, with all applicable derating applied. Common facility feeders fall between 4/0 AWG and 500 kcmil copper; for reference, 4/0 AWG copper EPR 15 kV in duct is approximately 260-290 A and 500 kcmil approximately 370-400 A before derating, with the exact value set by the installation conditions. (7.1)

NOTE Cable ampacity shall be coordinated with the served transformer kVA, the fuse or relay protection, and the cable impedance, so that the feeder cable is not the thermal weak link of the circuit even when the overcurrent device is correctly sized. (7.2)

NOTE The cable shall not exceed its temperature limits in any operating state: 90 °C continuous for XLPE and 105 °C for EPR, 130 °C (XLPE) or 140 °C (EPR) emergency overload, and 250 °C short-circuit. (7.3)

NOTE Terminations and splices are engineered fittings, not generic field assemblies; using a misclassed or generic fitting is a leading cause of in-service medium-voltage cable failure. Terminations shall be selected by class per IEEE 48 and splices by type per IEEE 404, matched to the cable construction, voltage class, and conductor size. (8.1)

NOTE Termination type is selected for the service condition. Heat-shrink and cold-shrink terminations are common for both indoor and outdoor use; pre-molded (push-on) terminations and separable connectors suit dead-front equipment interfaces; fluid-filled terminations serve specific outdoor applications. (8.2)

NOTE Splice type shall match the cable construction and the splice location, which may be a manhole, a direct-buried location, or a vault. (8.3)

NOTE Spare conduits shall be reserved in the duct bank, and adequate bending and racking room shall be provided in manholes, in coordination with Underground Ductbank, so that cable can be pulled, racked, and terminated without violating bend-radius limits. (9.4)

NOTE Field acceptance testing proves the integrity of the installed system after the operations most likely to have damaged it, and is performed before energization. The required tests are insulation resistance, shield continuity, and an AC withstand by the VLF method. (10.1)

NOTE DC hipot testing shall not be used on XLPE- or EPR-insulated medium-voltage cable, because DC voltage injects and traps space charge in extruded dielectric, causing latent dielectric damage and post-test failures. The acceptance withstand shall instead use the very-low-frequency (VLF) AC method of IEEE 400.2. (10.2)

NOTE Cable shall be delivered on reels with each end sealed against moisture ingress, because moisture in the conductor strand or under the shield migrates along the cable and degrades the insulation over its life. (11.1)

NOTE The Contractor shall warrant the installed cable system, including all splices and terminations, against defects in materials and workmanship for the project warranty period, and shall repair or replace failed cable, splices, or terminations at no cost to the Owner during that period. (12.1)

NOTE A reserve of splice and termination kits matched to the installed cable should be turned over to the Owner, so that an in-service failure can be repaired without waiting on procurement of voltage-class-specific kits. (13.1)