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Product

instrumentation cable seriesRCC-E K1 / IEC 60584-3Type K / N / E / J Class 1CETM Core Exit Temp

74C068 SH MT K1 NA Nuclear K1 Class 1E Thermocouple CableRCC-E K1 / Class 1E LOCA-qualified Type K, N, J, E & T nuclear thermocouple cable

74C068 SH MT K1 NA Nuclear K1 Class 1E Thermocouple Cable with IEC 60584-3 Class 1 thermocouple-grade or extension alloys (Type K NiCr/NiAl, Type N NiCrSi/NiSi, Type J, Type E), radiation-cross-linked K1 EPDM insulation, individual +.

RCC-E K1 / IEEE 323
Indiv + Overall Screen
IEEE 383 Halogen-Free
LOCA Steam & Spray
Order designation
74C068 SH MT K1 NA 4P×1.0-KX
Outer Ø ≈
15.6 mm
Weight ≈
335 kg/km
TC loop R
1.43 Ω/m
Min. bend radius
125 mm
All sizes (6)
Request a quoteDatasheetWhatsApp
Engineering reply in 2 business hoursCut-to-length export drumsEN 10204 3.1 certificate per drum
Qualification
RCC-E K1 / 1E
Mesure Thermocouple (MT)
TC calibration
Type K · N · E ·
IEC 60584-3 Tolerance Class 1
EMF tolerance
±1.5 °C (Type K)
Special limits (±1.1 °C) opt.
Radiation dose
≥ 2.0 MGy
Zero EMF drift after 200 Mrad
LOCA peak
+170 °C / 5.5 ba
High IR prevents EMF shunting
Conductor
0.50 to 1.5 mm²
Solid or 7-strand TC alloy

Typical values for this cable type, based on RCC-E K1 / IEC 60584-3 / IEEE 323 / IEEE 383 — confirmed in the datasheet and quotation for your order.

Application fit

Is 74C068 SH MT K1 NA right for your machine?

Links Core Exit Thermocouple Monitoring (CETM) junction boxes, Reactor Coolant System (RCS) hot/cold-leg thermowells and containment temperature sensors to Class 1E safety rooms.

Fixed installation

Suitable

Installed between mineral-insulated CETM head connectors, containment penetrations and reference junction boxes.

Switchgear & control cabinet wiring

Suitable

Routes millivolt Seebeck EMF signals to Reactor Protection and Subcooling Margin Monitor (SMM) racks.

Immersion & wet locations

Suitable

Ultra-high LOCA insulation resistance prevents parasitic galvanic/electrochemical EMF errors in steam.

Energy chain / drag chain

Not suitable

Fixed nuclear containment thermocouple cable; not for moving machinery drag chains.

Use PUR-HF Drag-Chain Cable
Typical machinesCore Exit Thermocouple Monitoring (CETM)Subcooling Margin Monitor (SMM) SystemsRCS Hot-Leg & Cold-Leg Temperature LoopsPressurizer & Steam Generator Relief ValvesContainment Atmosphere Post-LOCA Monitoring

Construction

Layer by layer

74C068 SH MT K1 NA showing matched positive/negative thermocouple alloy conductors (KX/K, NX/N, EX/E, JX/J), K1 radiation-cross-linked EPDM insulation, individual + overall tinned copper screens, and SH K1 halogen-free outer sheath.

12345
Schematic, not to scale — generated from the layer data
#LayerMaterial & reference
1Matched thermocouple / extension alloy conductorsSolid (Class 1) or 7-strand (Class 2) IEC 60584-3 Class 1 alloys: Type K (NiCr/NiAl), Type N (NiCrSi/NiSi), Type E (NiCr/CuNi) or Type J (Fe/CuNi)Calibrated from melt lot for ±1.1 °C / ±1.5 °C EMF accuracy
2High-IR K1 cross-linked EPDM dielectricRadiation-cross-linked nuclear K1 elastomer with ultra-low ionic leachatesEliminates battery-effect galvanic voltage in +170 °C LOCA steam
3Individual pair screens + matching TC drainAluminium/PET or copper/PET tape with tinned copper drain wire over each twisted thermocouple pairPrevents millivolt crosstalk between adjacent CETM channels
4Overall tinned copper wire braid screen≥ 85 % optical coverage tinned copper braid screenCommon-mode EMI rejection ≥ 120 dB at 50/60 Hz
5SH Zero-Halogen K1 Cross-Linked Outer SheathNuclear-grade Sans Halogène (SH) cross-linked elastomer (Green for Type K, Pink for Type N, Violet for Type E, or Black)IEEE 383 & IEC 60332-3-24 compliant

74C068 SH MT K1 NA — Type KX/K (NiCr/NiAl)

1 to 24 pairs × 0.5 / 1.0 / 1.5 mm² Type K Class 1 for PWR/EPR Core Exit Thermocouple Monitoring (CETM)

74C068 SH MT K1 NA — Type NX/N (Nicrosil/Nisil)

1 to 12 pairs Type N Class 1 with enhanced nuclear transmutation and high-temp oxidation stability

Technical data

Ratings & operating limits

Typical values: Typical values for this cable type, based on RCC-E K1 / IEC 60584-3 / IEEE 323 / IEEE 383. Values for your order are confirmed in the datasheet and quotation.

Electrical

Thermocouple calibrations
Type K (KX/K) · Type N (NX/N) · Type E (EX/E) · Type J (JX/J)
EMF accuracy class
IEC 60584-3 Class 1 (±1.5 °C) / ASTM E230 Special (±1.1 °C)
Loop resistance @ 20 °C
≈ 1.43 Ω/m (Type K 1.0 mm²) · ≈ 0.95 Ω/m (Type K 1.5 mm²)
Insulation resistance
≥ 5,000 MΩ·km @ 20 °C · ≥ 10 MΩ·km during +170 °C LOCA

Thermal

Continuous operating temp.
-25 °C to +90 °C (+150 °C extension calibration range)
LOCA / HELB accident peak
+170 °C to +210 °C saturated/superheated steam
60-year thermal aging
Arrhenius-qualified for 60 years @ +55 °C containment ambient

Mechanical

Min. bend radius
8 × OD (fixed) · 12 × OD (installation)
Seismic qualification
IEEE 344 / IEC 60980 OBE & SSE qualified
Conductor construction
Solid (Class 1) or 7-strand (Class 2) matched alloy

Resistance

Gamma radiation dose
≥ 2.0 MGy (200 Mrad) without Seebeck EMF decalibration
LOCA chemical spray
30-day boric acid + NaOH spray & submergence pass
Flame & halogen-free (SH)
IEEE 383 / IEC 60332-3-24, IEC 60754-2 & IEC 61034-2

Reference standards

Nuclear & TC standards
RCC-E K1 · IEC 60584-3 · IEEE 323 · IEEE 383 · RG 1.97
Quality assurance
ISO 19443 / ASME NQA-1 / 10 CFR 50 App B
RoHS & REACH
2011/65/EU & EC 1907/2006 compliant

Identification

Code breakdown
SH=Halogen-Free · MT=Mesure Thermocouple · K1=In-Containment · NA=Unarmoured
Core colour code (IEC)
Type K: Green(+)/White(-) · Type N: Pink(+)/White(-) · Type E: Violet(+)/White(-)
Customs tariff (HS)
8544.4993

Sizes

6 standard 74C068 SH MT K1 NA nuclear thermocouple configurations

Dimensional, weight and loop resistance data for RCC-E K1 Class 1E Type K and Type N thermocouple cables.

Dimensions & loop resistance
Order designationTC type & pairsOuter Ø ≈
mm		Weight ≈
kg/km		Loop R
Ω/m		Min. bend R
mm		Enquiry
RCC-E K1 / Class 1E Thermocouple Cables (IEC 60584-3 Class 1)
74C068 SH MT K1 NA 1P×1.0-KX1 Pair × 1.0 mm² Type KX (NiCr/NiAl)8.81081.4370
74C068 SH MT K1 NA 2P×1.0-KX2 Pairs × 1.0 mm² Type KX12.82151.43102
74C068 SH MT K1 NA 4P×1.0-KX4 Pairs × 1.0 mm² Type KX15.63351.43125
74C068 SH MT K1 NA 8P×1.0-KX8 Pairs × 1.0 mm² Type KX (CETM)19.85401.43158
74C068 SH MT K1 NA 12P×1.5-KX12 Pairs × 1.5 mm² Type KX (CETM)25.49100.95203
74C068 SH MT K1 NA 4P×1.0-NX4 Pairs × 1.0 mm² Type NX (Nicrosil/Nisil)15.63351.72125
  • Typical values for this cable type; dimensions and weights for your order are confirmed in the quotation.
  • Available in IEC 60584-3 (Green/Pink/Violet) or ANSI MC96.1 / ASTM E230 (Yellow/Orange/Purple) colour coding.

Quality & approvals

Testing & inspection

Routine tests on every production length, sample and type tests per batch — documented on an EN 10204 3.1 inspection certificate.

  1. ConductorClass 5 stranding
  2. Spark test100 % in-line
  3. Lay-upCores, earth, fillers
  4. SheathingInner, braid / screen, outer
  5. Electrical testsAC voltage, resistance
  6. DimensionsOD, wall thickness
  7. Inspection documents & dispatchDrum & dispatch
Testing & inspectionTest value / referenceFrequency
Routine tests
100 % Seebeck EMF calibration, 2.0 kV AC dielectric & IR testEMF within IEC 60584-3 Class 1 (±1.5 °C) and IR ≥ 5,000 MΩ·kmEvery manufactured drum length
Sample tests
LOCA +170 °C steam temperature error & IR retention testInduced thermal-shunt EMF error < 1.0 °C during peak LOCA steamK1 Type Qualification
2.0 MGy gamma irradiation + IEEE 383 vertical flame testZero alloy decalibration and pass vertical tray flame burnK1 Type Qualification

Inspection certificate

Issued with every drum, listing the routine test results for that length.

Product approvals

RCC-E K1 & IEC 60584-3 Class 1IEEE Std 323 & IEEE Std 383ISO 19443 Nuclear QA

Company certificates

ISO 9001ISO 14001ISO 45001VDE marks approvalUL / cULCE · LVD / EMC

Marking & supply

Ordering & delivery

Sheath marking

TEBAOFLEX 74C068 SH MT K1 NA TYPE KX CLASS 1 RCC-E K1
Delivery form
Fumigated wooden drums, steel reels or precision spools
Standard lengths
500 m · 1000 m (or custom cut/spooled lengths)
MOQ
100 m (standard) · 500 m (custom)
Lead time
2–4 weeks ex-works
Incoterms
EXW, FOB, CIF, DAP

Technical documents

Downloads

PDF74C068 SH MT K1 NA Nuclear K1 Class 1E Thermocouple Cable – technical datasheet6 sizes · construction, technical data, approvalsXLSX74C068 SH MT K1 NA spec data (Excel)All 6 sizes with dimensions and data, for your BOM or quotation
Revision
2026-10-20
Updated
2026-10-20

FAQ

Questions engineers ask first

Not covered here? Send your drawing — an engineer replies within 2 business hours.

Why must Core Exit Thermocouple Monitoring (CETM) cables use true thermocouple-grade alloys (Type K / N) across containment?
Core exit thermocouples measure reactor coolant temperature leaving the fuel assemblies (up to +1,200 °C during a severe accident). Because the containment ambient temperature itself rises to +170 °C during a LOCA, the cable between the reactor head connector and the outside reference junction box must use matched thermocouple-grade alloys (KX/K or NX/N) with high-IR K1 insulation so no spurious cold-junction error is introduced inside containment.
How does low insulation resistance during a LOCA affect a thermocouple reading?
Because a Type K thermocouple generates only ~41 µV/°C and has a high loop resistance (~1.43 Ω/m), any ionic moisture ingress or drop in insulation resistance at +170 °C creates both resistive shunting and an electrochemical 'wet-battery' voltage between the heterogeneous NiCr and NiAl conductors. Our K1 EPDM dielectric prevents ionic conduction during LOCA steam.
Why do many Generation III+ reactors specify Type N (Nicrosil/Nisil) alongside Type K?
Type N avoids the short-range magnetic ordering drift seen in Type K Alumel between +250 °C and +550 °C and has lower neutron-capture cross-section drift.
Can we order 74C068 SH MT K1 NA with ANSI MC96.1 colours instead of IEC 60584-3?
Yes. Both IEC 60584-3 (Type K Green/White) and ANSI/ASTM E230 (Type K Yellow/Red) colour codes are supplied.

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74C068 SH MT K1 NA Nuclear K1 Class 1E Thermocouple Cable

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