CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 MEDIUM VOLTAGE TERMINATIONS General Information about Heat-shrinkable Terminations 3.00 T50NS Terminations for 5-8 kv, 1/C and 3/C Extruded Dielectric 3.10 Non-shielded Power Cables T-UD 1/C Terminations 15-35 kv, Bare Concentric Neutral and 3.20 Jacketed Concentric Neutral Cables T-LC 1/C Terminations 15-35 kv, Extruded Dielectric, Type LC 3.30 Longitudinally Corrugated Shielded Cable T-G 1/C Terminations 5-35 kv, Extruded Dielectric, XLP/EPR 3.40 tape, Wire Shielded or Lead Sheathed, XLP/EPR Cable T-3G 3/C Terminations 5-35 kv, Extruded Dielectric, Armored 3.50 and Unarmored, Tape or Wire Shielded Cable
T Series Heat Shrinkable Cable Terminations GENERAL INFORMATION Termination Considerations IEEE 48-1996 IEEE Test Procedures and Requirements for Alternating- Current Cable Terminations 2.5 kv through 765 kv are the standard to which INERTIA-REPL terminations conform. IEEE Std 48-1996 defines a termination as a device used for terminating alternatingcurrent power cables having laminated or extruded insulation rated 2.5 kv and above. They are classified accordingly: A) Class 1 Termination: Provides electric stress control for the cable insulation shield terminus; provides complete external leakage insulation between the cable conductor(s) and ground; and provides a seal to the end of the cable against the entrance of the external environment and maintains the operating design pressure, if any, of the cable system. This class is divided into three types: Class 1A: For use on extruded dielectric cable Class 1B: For use on laminated dielectric cable Class 1C: Expressly for pressuretype cable systems B) Class 2 Termination: Provides electric stress control for the cable insulation shield terminus, and provides complete external leakage insulation between the cable conductor(s) and ground. C) Class 3 Termination: Provides electric stress control for the cable insulation shield terminus. INERTIA-REPL terminators are Class 1A terminations only. They are designed for both bare and jacketed concentric neutral cables, longitudinally corrugated (Type LC), drain wire, and metallic tape shielded cables. Terminations are available with and without external grounding kits, and in both indoor and outdoor configurations. Separately applied sheds provide the additional external creepage necessary for outdoor applications which allow the termination to be easily configured for either upright or inverted configurations. The non-tracking outer tube provides greater than 30 years of service; even in very heavily polluted environments. Electrical Stress Problem: The insulation shield must be removed in order to provide adequate strike distance for the voltage cable being terminated. At that cutback point, the electrical field concentrates causes high electrical stress. These stresses will cause the air to break down which results in partial discharges that will destroy the cable insulation and cause premature failure of the cable at that point (see Illustration 1 at right). Stress Gradient Solution: The INERTIA-REPL termination employs stress gradient mastic and a stress control tube to spread out the equipotential lines, distributing the electrical field and reducing the electrical stress to the cable insulations operating level. This is achieved by the unique resistive and capacitive properties of the heat-shrinkable material (see Illustration 2 at right). Insulation shield Insulation shield Equipotential lines Insulation shield Prepared Cable End Without Stress Control Device Highly stressed area 40% 50% 60% subject to partial discharge 70% 30% 20% 80% 10% 90% line voltage Equipotential lines Conductor (100% line voltage) Stress Gradient Mastic Illustration 1. 10% 15% 20% 25% 5 % 30% 40% 60% Conductor (100% line voltage) Insulation Class III Terminated Cable with INERTIA-REPL Stress Control System Illustration 2. Stress control tube 80% line voltage Insulation 3.00
If the termination is installed to close to another phase or ground, the b b electric stress in the air gap will rise to a level where corona or flashover c c may occur. The table below and illustrations at right, indicate the minimum clearances needed 45 between 45 various termination configurations. These clearances are based on IEEE Basic Impulse Levels (BIL). bd cb 45 d b d b a c d a c d a c a c Phase/ground Same phase Phase/phase Phase/phase staggered adjacent staggered Minimum Phase Air Clearances* to Phase groundto inches, ground (millimeters): Same phase Same phase Between Between phases phases Adjacent Adjacent phase stagger phase stagger Cable Voltage Class BIL a b c d (phase-phase) Nom. 5 kv-8 kv 95 6.5 (160) 3.5 (90) 1.2 (30) 0.8 (20) 15 kv 110 7.0 (175) 4.0 (100) 1.4 (35) 0.9 (23) 25 kv 125 9.0 (225) 6.0 (150) 1.6 (40) 1.0 (25) 25 kv 150 9.0 (225) 6.0 (150) 1.6 (40) 1.0 (25) 35 kv 200 13.0 (325) 9.0 (225) 2.0 (50) 1.4 (35) Radius Radius Note: Recommended Bending Radius: The air clearances above are based on Diameter normal Diameter INERTIA-REPL terminations can operating environments defined in IEEE-48-1996. be bent to the same bending radius as the cable. Cable ends Extremely humid or poorly ventilated enclosures may require greater spacing to meet these BIL should not be bent to a radius less levels. For shedded terminations, the distances than ten times (10x) the jacket Diameter shown are between shed edges or between a diameter or manufacturer recommendations; Figure 5. Figure whichever 5. is greater. shed edge and ground. Bending radius Bending radius Termination Tests to IEEE 48-1996 Standard Test Procedures and Requirements for Alternating Current Cable Terminations 2.5 kv Through 765 kv Radius TEST DESCRIPTION Sequence INERTIA-REPL Product and Voltage Class T080 T150 T250 T350 5-8 kv 15 kv 25 kv 35 kv Partial discharge (corona) extinction voltage < 5 pc 7.5 kv 13.0 kv 21.5 kv 30.0 kv Power frequency voltage 1 min. dry withstand 35 kv 50 kv 65 kv 90 kv Power frequency voltage 6 hr. dry withstand 25 kv 35 kv 55 kv 75 kv Power frequency voltage 10 sec. wet withstand 30 kv 45 kv 60 kv 80 kv Direct voltage 15 min. dry withstand 65 kv 75 kv 105 kv 140 kv Lightning impulse voltage withstand (1.2 x 50 µs wave) 95 kv 110 kv 150 kv 200 kv Partial discharge (corona) extinction voltage < 5 pc 7.5 kv 13.0 kv 21.5 kv 30.0 kv Cyclic Aging 30 cycles 130 C for 6 hours/day while at 15 kv 26 kv 43 kv 60 kv Lightning impulse voltage withstand (1.2 x 50 µs wave) 95 kv 110 kv 150 kv 200 kv Partial discharge (corona) extinction voltage <5 pc 7.5 kv 13.0 kv 21.5 kv 30.0 kv Pressure leak test: 30 PSIG for 1 hr., 15 PSIG for 2 hrs., Pass Pass Pass Pass 7.5 PSIG for 6 hrs. and 67 Pa to < 670 Pa for 30 min. Continuous current rating Equal to cable ampacity- - -- - - - - - - - - - - - - - - - - - - - - - - - - 3.01
T50NS Series 5-8 kv Heat Shrinkable Cable Terminations for 1/C and 3/C Non-shielded Cables CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 T50N series terminations are 1/C heat-shrinkable 5 kv-8 kv terminators for nonshielded power cable. T50N3 series terminations are 3/C heatshrinkable 5 kv-8 kv terminators for nonshielded armored or unarmored power cable. Termination Features Heat activated seals provide the best moisture ingress prevention Non-tracking surface prevents corona degradation. Lightweight construction allows connection directly to the cut-out or fuse without additional suppor Slim profile allows for placement of terminations in tight spaces Terminations are for both indoor and outdoor applications. No sheds are required for outdoor applications. Product Selection for 1/C Cable Selection is easy. First lookup the conductor size to be terminated. Select the part number and confirm the dimensional data. This is important if your cable size is at either extreme of the range shown for the selected kit. T52N Voltage Conductor Size Indoor/Outdoor Insulation Diameter Jacket Diameter Class Range Part No. Minimum Maximum 5-8 kv # 4-2/0 AWG T51N 0.40 (10 mm) 0.95 (24 mm) 3/0-500 kcmil T52N 0.70 (18 mm) 1.30 (33 mm) 750-1500 kcmil T53N 1.10 (28 mm) 2.15 (55 mm) Product Selection for 3/C and 3/C Armored Cable Anti-track sealant Nontracking tube Anti-track sealant Voltage Conductor Size Indoor/Outdoor Insulation Diameter Jacket Diameter Class Range Part No. Minimum Maximum 5-8 kv # 4-2/0 AWG T51N3 0.40 (10 mm) 3.00 (76 mm) 3/0-500 kcmil T52N3 0.70 (18 mm) 3.30 (84 mm) 750-1500 kcmil T53N3 1.10 (28 mm) 5.00 (127 mm) Contents include the non-tracking, corona resistant tube, anti-track sealants, and installation guide. Compression or mechanical connectors for the conductor or ground wires are not provided. They must be purchased separately. T52N3 Packaging includes three (3) single-phase kits per box. Boxes are labeled in accordance with the requirements of IEEE 48-1996. 3.10
T_UD Series 1/C Heat Shrinkable Cable Terminations for 15 kv-35 kv Bare Concentric Neutral and Jacketed Concentric Neutral Cables CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 T _UD series terminations are heatshrinkable, Class 1A, 15 kv-35 kv terminators for bare and jacketed concentric neutral cables. Termination Features Heat activated seals provide the best moisture ingress prevention Nontracking surface provides long service life in hostile environments Lightweight construction allows connection directly to the cut-out or fuse without additional support Slim profile allows for placement of terminations in confined spaces Outdoor terminations are only required where subject to direct precipitation or exposure to sunlight. The indoor version is acceptable for use in padmounted enclosures. Product Selection: All dimensions are in inches (milimeters) Voltage Conductor Size Indoor Kit Outdoor Kit Insulation Diameter Jacket Diameter Class Range Part No. Part No. Minimum-Maximum Maximum #2-3/0 AWG T151UD T151SUD 0.60-0.95 (15-24) 1.45 (37) 15 kv 4/0-350 kcmil T152UD T152SUD 0.80-1.25 (20-32) 1.85 (47) 175-220 mils 400-1000 kcmil T153UD T153SUD 1.10-1.65 (28-42) 2.20 (56) 1250-2000 kcmil T154UD T154SUD 1.60-2.45 (41-62) 2.70 (69) 25 kv #2-400 kcmil T251UD T251SUD 0.80-1.25 (20-32) 1.80 (46) 260 mils 400-1000 kcmil T252UD T252SUD 1.10-1.70 (28-43) 2.50 (64) 1000-1500 kcmil T253UD T253SUD 1.60-2.45 (41-62) 2.70 (69) 35 kv #1-250 kcmil T351UD T351SUD 0.80-1.25 (20-32) 1.50 (38) 345 mils 250-1250 kcmil T352UD T352SUD 1.10-1.85 (28-47) 2.10 (53) 750-1750 kcmil T353UD T353SUD 1.60-2.45 (41-62) 2.75 (70) Selection is easy. Lookup the conductor size for the voltage class of cable to be terminated. Select the indoor or outdoor termination part number and confirm the dimensional data. This is important if your cable size is at either extreme of the range shown for the selected kit. Anti-track sealant Nontracking tube Nontracking shed Stress control tube Stress gradient mastic Anti-track sealant Bare Concentric Neutral Contents include the nontracking tube, anti-track sealants, the stress gradient mastic, the stress gradient tube and shed(s), as required, for outdoor kits. Jacketed Concentric Neutral Packaging includes one (1) singlephase kit per box. Boxes are labeled in accordance with the requirements of IEEE 48-1996. Compression or mechanical connectors for the conductor or for the shield grounding are not provided. They must be purchased separately. 3.20
T_LC Series 1/C Heat Shrinkable Cable Terminations for 15kV-35 kv Type LC Longitudinally Corrugated XLP/EPR Cables T _LC series terminations are heatshrinkable, Class 1A, 15 kv-35 kv terminators for Type LC longitudinally corrugated shielded power cables. CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 Termination Features Heat activated seals provide the best moisture ingress prevention Nontracking surface provides long service life in hostile environments Lightweight construction allows connection directly to the cut-out or fuse without additional support Slim profile allows for placement of terminations in confined spaces Separate blocked ground braids for each half on the corrugated shield Outdoor terminations are only required where subject to direct precipitation or exposure to sunlight. Product Selection: All dimensions are in inches (milimeters) Voltage Conductor Size Indoor Kit Outdoor Kit Insulation Diameter Jacket Diameter Class Range Part No. Part No. Minimum-Maximum Maximum #2-3/0 AWG T151LC T151SLC 0.65-1.00 (17-25) 1.45 (37) 15 kv 4/0-350 kcmil T152LC T152SLC 0.85-1.40 (22-36) 1.85 (47) 175-220 mils 500-1000 kcmil T153LC T153SLC 1.15-1.70 (29-43) 2.20 (56) 1250-2000 kcmil T154LC T154SLC 1.60-2.15 (41-55) 2.70 (69) 25 kv #2-400 kcmil T251LC T251SLC 0.85-1.40 (22-36) 1.80 (46) 260 mils 400-1000 kcmil T252LC T252SLC 1.25-1.80 (34-46) 2.50 (64) 1000-1500 kcmil T253LC T253SLC 1.60-2.10 (41-53) 2.70 (69) 35 kv #1-250 kcmil T351LC T351SLC 1.05-1.40 (27-36) 1.90 (48) 345 mils 250-1250 kcmil T352LC T352SLC 1.25-2.10 (32-53) 2.60 (66) Selection is easy. Lookup the conductor size for the voltage class of cable to be terminated. Select the indoor or outdoor termination part number and confirm the dimensional data. This is important if your cable size is at either extreme of the range shown for the selected kit. Contents include non-tracking tube, anti-track sealants, stress gradient mastic, stress gradient tube and shed(s), as required, for outdoor kits and a dual solder-blocked braid external grounding kit for additional fault current ampacity. Compression or mechanical connectors for the conductor or for the shield grounding are not provided. They must be purchased separately. Contents: Packaging includes one (1) single-phase kit per box. Boxes are labeled in accordance with the requirements of IEEE 48-1996. 3.30
T_G Series 1/C Heat Shrinkable Cable Terminations for 5 kv-35 kv Copper Tape, Drain Wire or Lead Sheathed, XLP/EPR Cables CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 T _G series terminations are heatshrinkable, Class 1A, 5 kv-35 kv terminators for extruded dielectric (XLP/EPR), copper tape, drain wire shielded or UniShield cables. Termination Features Heat activated seals provide the best moisture ingress prevention Nontracking surface provides long service life in hostile environments Lightweight construction allows connection directly to the cut-out or fuse without additional support Slim profile allows for placement of terminations in confined spaces Available both with and without the external grounding kit Selection is easy. Lookup the conductor size for the voltage class of cable to be terminated. Product Selection: All dimensions are in inches (milimeters) Conductor Size Range by Voltage Class Indoor Kit Outdoor Kit Insulation Diameter Jacket Dia. Part No. Part No. Minimum-Maximum Maximum 5 kv 8 kv Outdoor terminations are only required when subjected to direct precipitation or exposure to sunlight. The indoor version is acceptable for use in padmounted enclosures. For wire shielded or UniShield cables, use the T _X kits instead of the T _G kit to save money when an external grounding kit is unnecessary or not desired. Select the indoor or outdoor termination part number and confirm the dimensional data. This is important if your cable size is at either extreme of the range shown for the selected kit. #4-#1 AWG #6-#2 AWG T081G T081SG 0.35-0.60 (9-15) 0.95 (24) 1/0-250 kcmil #1-4/0 AWG T082G T082SG 0.60-0.95 (15-24) 1.20 (30) 300-500 kcmil 250-500 kcmil T083G T083SG 0.80-1.25 (20-32) 1.50 (38) 600-1750 kcmil 600-1750 kcmil T084G T084SG 1.10-1.75 (28-44) 2.10 (53) 1500-2500 kcmil 2000-2500 kcmil T085G T085SG 1.60-2.45 (41-62) 2.75 (70) 15 kv #4-4/0 AWG T151G T151SG 0.60-0.95 (15-24) 1.45 (36) 3/0-350 kcmil T152G T152SG 0.80-1.25 (20-32) 1.50 (38) 400-1000 kcmil T153G T153SG 1.10-1.65 (28-42) 2.10 (53) 1250-2500 kcmil T154G T154SG 1.60-2.45 (41-62) 2.75 (70) 25 kv #2-350 kcmil T251G T251SG 0.80-1.25 (20-32) 1.50 (38) 350-1000 kcmil T252G T252SG 1.10-1.70 (28-43) 2.10 (53) 1000-1750 kcmil T253G T253SG 1.60-2.45 (41-62) 2.75 (70) 2000-2500 kcmil T254G T254SG 2.05-3.00 (52-76) 3.45 (88) 35 kv #1-1/0 AWG T351G T351SG 0.80-1.25 (20-32) 1.50 (38) 2/0-500 kcmil T352G T352SG 1.10-1.85 (28-47) 2.10 (53) 750-1750 kcmil T353G T353SG 1.60-2.45 (41-62) 2.75 (70) 2000-2500 kcmil T354G T354SG 2.05-3.00 (52-76) 3.45 (88) UniShield is a registered trademark of General Cable Technologies Corporation 3.40
Contents: A single-core indoor kit for wire shielded or UniShield cable has the following components: nontracking tube stress gradient mastic stress control tube anti-track sealant installation guide A single-core outdoor kit for wire shielded or UniShield cable has the following components: nontracking tube stress gradient mastic stress control tube anti-track sealant nontracking sheds installation guide A single-core indoor kit for metallic tape shielded cable has the following components: nontracking tube stress gradient mastic stress control tube anti-track sealant external grounding kit installation guide - constant force spring - solder-blocked braid - copper foil tape Packaging: Packaging for these kits include three (3) single-phase kits per box. Boxes are labeled in accordance with the requirements of IEEE 48-1996. Compression connectors for the conductor or for shield grounding are not provided. They must be purchased separately. A single-core outdoor kit for metallic tape shielded cable has the following components: nontracking tube stress gradient mastic stress control tube nontracking sheds anti-track sealant installation guide external grounding kit - constant force spring - solder-blocked braid - copper foil tape 3.41
T_3G Series 3/C Heat Shrinkable Cable Terminations for 5 kv-35 kv Copper Tape, Drain Wire Shielded Armored, or Unarmored Cables T _3X and T_3B series terminations are three-core heat-shrinkable, Class 1A, 5 kv-35 kv terminators for extruded dielectric (XLP/EPR), tape, wire shielded, or UniShield, 3/C armored or unarmored cables. Termination Features Heat activated seals provide the best moisture ingress prevention Nontracking surface provides long service life in hostile environments Lightweight construction allows connection directly to the cut-out or fuse without additional support Slim profile allows for placement of terminations in confined spaces Available both with and without the external grounding kit CAT010509- Rev 1. 2009 INERTIA- REPL INC. All rights reserved Printed January 2009 Outdoor terminations are only required when subjected to direct precipitation or exposure to sunlight. The indoor version is acceptable for use in padmounted enclosures. For wire shielded or UniShield cables, use the T_ 3X, T_ 3SX, T_ 3X or T_ S3X kits instead of the T_ G3B, T_ 3SGB, T_ G3B or T_ SG3B kits when an external grounding kit is unnecessary. The T_3X kits without breakout boots are well suited for indoor applications and for use with armor terminators. T_3B kits are suited for outdoor applications or wherever a sealed crotch is desired. There are two kinds of kits available in both indoor and outdoor variations: The T_3B kits contain three core jacketing tubes to keep the metallic shielding in intimate contact with the insulation shield of the cable. Outdoor Termination for Armored or Unarmored Jacketed Cable There are also three adhesive lined tubes for rejacketing and sealing the ground wire(s). A cable breakout boot and sealant are also provided to seal the crotch area of the threecore cable.this kit is used whenever sealing of the three-core cable is required for indoor applications and always on outdoor applications The T_3X kits contain three core jacketing tubes to keep the metallic shielding in close contact with the insulation shield of the cable. There are also three adhesive lined tubes for rejacketing and sealing the ground wire(s). T_3X kits are used whenever sealing of the three-core cable is not required, or when an armor terminator (JAG type, for example) is to be Indoor Termination with Armor Terminator (not supplied) used in conjunction with the kit for a sealed cable end. Contents: Everything is included to construct a three-core termination. The kit includes three (3) single-core terminations, plus three (3) each rejacketing phase and ground wire tubes. A cable breakout boot for sealing the crotch is also brovided in the T_3B kits. Contents: Packaging includes one (1) three-phase kit per box. Boxes are labeled in accordance with the requirements of IEEE 48-1996. 3.50
Ordering: 1. Determine if your application requires a boot to seal the three-core cable. If unsure, select the kit with the boot. 2. Lookup the conductor size for the voltage class of cable to be terminated and select the indoor or outdoor termination part number. 3. Confirm the dimensional data. This is important if your cable size is at either extreme of the range shown for the selected kit. Core tubes (3) Ground tubes (3) Breakout boot Black sealant T083SG-3B Cable tie Ground tubes (3) T083G-3X Product Selection: All dimensions are in inches (milimeters) Conductor Indoor Kit Part Number Outdoor Kit Part Number Insulation Dia. Jacket Dia. Range W/ BOOT NO BOOT W/ BOOT NO BOOT Min.- Max. Max. 5 kv #4-#1 AWG T081G-3B T081G-3X T081SG-3B T081SG-3X 0.35-0.60 (9-15) 0.95 (24) 1/0-250 kcmil T082G-3B T082G-3X T082SG-3B T082SG-3X 0.60-0.95 (15-24) 1.20 (30) 300-500 kcmil T083G-3B T083G-3X T083SG-3B T083SG-3X 0.80-1.25 (20-32) 1.50 (38) 600-1000 kcmil T084G-3B T084G-3X T084SG-3B T084SG-3X 1.10-1.75 (28-44) 2.10 (53) 8 kv #6-#2 AWG T081G-3B T081G-3X T081SG-3B T081SG-3X 0.35-0.60 (9-15) 0.95 (24) #1-4/0 AWG T082G-3B T082G-3X T082SG-3B T082SG-3X 0.60-0.95 (15-24) 1.20 (30) 250-500 kcmil T083G-3B T083G-3X T083SG-3B T083SG-3X 0.80-1.25 (20-32) 1.50 (38) 600-1000 kcmil T084G-3B T084G-3X T084SG-3B T084SG-3X 1.10-1.75 (28-44) 2.10 (53) 15 kv #4-1/0 AWG T151G-3B T151G-3X T151SG-3B T151SG-3X 0.60-0.95 (15-24) 1.45 (30) 2/0-350 kcmil T152G-3B T152G-3X T152SG-3B T152SG-3X 0.80-1.25 (20-32) 1.50 (38) 400-1000 kcmil T153G3B T153G-3X T153SG-3B T153SG-3X 1.10-1.65 (28-42) 2.10 (53) 25 kv #2-250 kcmil T251G3B T251G-3X T251SG-3B T251SG-3X 0.80-1.25 (20-32) 1.50 (38) 300-750 kcmil T252G3B T252G-3X T152SG-3B T152SG-3X 1.10-1.70 (28-43) 2.10 (53) 35 kv #1-1/0 AWG T351G3B T351G-3X T351SG-3B T351SG-3X 0.80-1.25 (20-32) 1.50 (38) 2/0-500 kcmil T352G3B T352G-3X T352SG-3B T352SG-3X 1.10-1.85 (28-47) 2.10 (53) 3-1/C to 3/C Conversion Kit Selection Kit Part No. 1/C Termination Kit Sizes Core Diameter Jacket Diameter NO BOOT for Conversion to 3/C Min.- Max.(Min.- Max) T3MODX T82, T83, T151, T152 & T251 0.5-1.25 (13-32mm) Not applicable T3MODY T84, T85, T153, T252, T351 & T352 1.0-1.8 (25-55mm) Not applicable With BOOT T3MODA T81, T82, T83,T151, T152 & T251 0.5-1.25 (15-32mm) 1.15-3.25 (32-98mm) T3MODB T84, T153, T252, T351 & 352 1.0-1.8 (25-46mm) 2.65-5.30 (67-135mm) Note: The 3X and 3Y kits are used when converting 3/C cables armored or unarmored, where no seal is required, or an armor terminator or TECK connector is required to seal the individual cores. The 3A and 3B kits are used for converting 3/C cables armored or unarmored, when the cable breakout boot is used to seal the individual cores. 3.51