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Product

instrumentation cable seriesMIL-DTL-24643/42Type J (Fe / CuNi)2, 3 & 4 Shielded Pairs

LS2SJ / LS3SJ / LS4SJ MIL-DTL-24643 LS2SJ / LS3SJ / LS4SJMIL-DTL-24643/42 low-smoke zero-halogen shipboard Type J thermocouple extension cable

MIL-DTL-24643/42 (LS2SJ, LS3SJ, LS4SJ) Naval Shipboard Thermocouple Extension Cable with 2, 3 or 4 shielded twisted pairs of Type JX Iron/Constantan conductors, cross-linked polyolefin insulation, tinned copper pair shields, and.

MIL-DTL-24643/42
Naval Low-Smoke LSZH
Braided Pair Shields
Shipboard Marine Duty
Order designation
LS2SJ (M24643/42-01UN)
Max. outer Ø
12.7 mm
Weight ≈
195 kg/km
TC loop R
1.17 Ω/m
Min. bend radius
76 mm
All sizes (6)
Request a quoteDatasheetWhatsApp
Engineering reply in 2 business hoursCut-to-length export drumsEN 10204 3.1 certificate per drum
Military spec
M24643/42
LS2SJ / LS3SJ / LS4SJ
TC calibration
Type J / JX
Iron (+) / Constantan (-)
Pair count
2, 3 or 4 pairs
LS2SJ (2P), LS3SJ (3P), LS4SJ (4P)
Conductor size
20 AWG (7-wire)
Stranded Fe & CuNi alloys
Temperature
-30 to +105 °C
Cross-linked polyolefin core
Armour options
-UN or -AN
Unarmoured or Al-braid armoured

Typical values for this cable type, based on MIL-DTL-24643/42 (M24643/42) / ASTM E230 — confirmed in the datasheet and quotation for your order.

Application fit

Is LS2SJ / LS3SJ / LS4SJ right for your machine?

Specified across surface combatants, auxiliary vessels and naval propulsion rooms for multi-point Type J exhaust, bearing, lube-oil and auxiliary boiler thermocouple extension harnesses.

Offshore platform & shipboard deck trays

Suitable

Routes multi-pair Type J temperature signals through naval shipboard bulkheads, machinery spaces and propulsion consoles.

Switchgear & control cabinet wiring

Suitable

Individual tinned-copper braided pair shields reject 60 Hz/400 Hz shipboard generator and radar EMI.

Fixed installation

Suitable

Available in Unarmoured (-UN) and braided Aluminum-Armoured (-AN) naval bulkhead variants.

Energy chain / drag chain

Not suitable

Fixed naval shipboard thermocouple cable; not for continuous industrial drag chains.

Use PUR-HF Drag-Chain Cable
Typical machinesNaval Surface Vessels & Coast Guard CuttersMarine Gas Turbine & Diesel Exhaust MonitoringPropulsion Reduction Gear & Bearing Temp LoopsShipboard Auxiliary Boiler & Steam SystemsNaval Damage Control & Machinery Automation

Construction

Layer by layer

MIL-DTL-24643/42 (LS2SJ / LS3SJ / LS4SJ) showing 20 AWG stranded Iron (+) and Constantan (-) twisted pairs, cross-linked polyolefin insulation, individual tinned copper braid shields with Jacketed pair isolation, and LSZH naval outer sheath (plus optional -AN aluminium braid armour).

1234
Schematic, not to scale — generated from the layer data
#LayerMaterial & reference
1Type J (Iron / Constantan) 20 AWG stranded pairs7-strand 20 AWG (0.52 mm²) solid-alloy Iron (JP, magnetic +) and Constantan Cu55Ni45 (JN, non-magnetic -) per ASTM E230Matched 50.4 µV/°C Seebeck EMF with ±2.2 °C / ±1.1 °C accuracy
2Halogen-free cross-linked polyolefin (XLPO) insulationRadiation-cross-linked low-smoke polyolefin primary core insulation (White + / Red - per ANSI MC96.1)Rated 300 V rms and +105 °C continuous shipboard service
3Individual tinned copper braided pair shieldEach twisted pair individually shielded with ≥ 85 % tinned copper wire braid and halogen-free pair jacketIsolated pair shields eliminate multi-point ground loops
4Low-Smoke Zero-Halogen (LS) cross-linked shipboard jacketNaval cross-linked polyolefin LSZH outer jacket (plus optional braided Aluminium armour on -AN variants)Meets MIL-DTL-24643 acid gas (< 2 %) and smoke optical density limits

LS2SJ (M24643/42-01UN / -01AN)

2 shielded pairs × 20 AWG Type J shipboard thermocouple cable (Unarmoured or Al-Armoured)

LS3SJ (M24643/42-02UN / -02AN)

3 shielded pairs × 20 AWG Type J shipboard thermocouple cable (Unarmoured or Al-Armoured)

LS4SJ (M24643/42-03UN / -03AN)

4 shielded pairs × 20 AWG Type J shipboard thermocouple cable (Unarmoured or Al-Armoured)

Technical data

Ratings & operating limits

Typical values: Typical values for this cable type, based on MIL-DTL-24643/42 (M24643/42) / ASTM E230. Values for your order are confirmed in the datasheet and quotation.

Electrical

Thermocouple calibration
Type J / JX (Iron + / Constantan -) per ASTM E230
Loop resistance @ 20 °C
≈ 1.17 Ω/m per 20 AWG Type J pair
Voltage & dielectric test
300 V rms working · 1,500 V AC rms dielectric test
Insulation resistance
≥ 1,000 MΩ·1000 ft (≥ 305 MΩ·km) @ 500 V DC

Thermal

Conductor temp. rating
-30 °C to +105 °C continuous shipboard ambient
EMF calibration range
0 °C to +200 °C (±2.2 °C Std / ±1.1 °C Special)
Cold bend test
-30 °C mandrel bend without cracking

Mechanical

Min. bend radius
6 × OD (-UN unarmoured) · 8 × OD (-AN armoured)
Pair shield coverage
≥ 85 % tinned copper wire braid on each pair
Armour braid (-AN)
Aluminum alloy 5056 wire braid over outer jacket

Resistance

Flame propagation
IEEE 1202 / UL 1581 vertical tray flame test
Halogen & acid gas
Zero halogen (< 0.2 % halogens, acid gas < 2.0 %)
Fluid resistance
Resistant to naval distillate fuel, lube oil & salt spray

Reference standards

Detail specification
MIL-DTL-24643/42 (Part numbers M24643/42-01 to -03)
Thermocouple standard
ASTM E230 / ANSI MC96.1
RoHS & REACH
2011/65/EU & EC 1907/2006 compliant

Identification

Core polarity colours
White (+ Iron, magnetic) & Red (- Constantan)
Military PIN format
M24643/42-01UN (LS2SJ), -02UN (LS3SJ), -03UN (LS4SJ)
Customs tariff (HS)
8544.4993

Sizes

6 standard MIL-DTL-24643/42 (LS2SJ / LS3SJ / LS4SJ) configurations

Military part numbers, pair counts, outer diameters and weights for unarmoured (-UN) and armoured (-AN) variants.

Dimensions & M24643/42 part numbers
Type & military PINPairs & armourMax. OD
mm		Weight ≈
kg/km		TC loop R
Ω/m		Min. bend R
mm		Enquiry
MIL-DTL-24643/42 Multi-Pair Type J Shipboard Cables
LS2SJ (M24643/42-01UN)2 Pairs × 20 AWG Type J · Unarmoured12.71951.1776
LS2SJA (M24643/42-01AN)2 Pairs × 20 AWG Type J · Al-Armoured14.22451.17114
LS3SJ (M24643/42-02UN)3 Pairs × 20 AWG Type J · Unarmoured13.72401.1782
LS3SJA (M24643/42-02AN)3 Pairs × 20 AWG Type J · Al-Armoured15.22981.17122
LS4SJ (M24643/42-03UN)4 Pairs × 20 AWG Type J · Unarmoured15.02951.1790
LS4SJA (M24643/42-03AN)4 Pairs × 20 AWG Type J · Al-Armoured16.53601.17132
  • Typical values for this cable type; dimensions and weights for your order are confirmed in the quotation.
  • All pairs are individually braided-shielded and jacketed prior to cabling under the overall LSZH sheath.

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 % ASTM E230 EMF calibration, 1.5 kV AC dielectric & IR testType J EMF within ±2.2 °C (±1.1 °C special) and zero dielectric breakdownEvery manufactured reel
Sample tests
Shield coverage & pair-to-shield isolation voltage test≥ 85 % tinned copper braid coverage and 500 V AC shield-to-shield isolationPer production lot
MIL-DTL-24643 smoke optical density, acid gas & IEEE 1202 flame testLow smoke index, < 0.2 % halogens and pass vertical tray burnQualification test

Inspection certificate

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

Product approvals

MIL-DTL-24643/42 CompliantASTM E230 / ANSI MC96.1 Type JIEEE 1202 Naval Low-Smoke

Company certificates

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

Marking & supply

Ordering & delivery

Sheath marking

TEBAOFLEX M24643/42-01UN LS2SJ 20AWG TYPE J LOW SMOKE
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

PDFLS2SJ / LS3SJ / LS4SJ MIL-DTL-24643 LS2SJ / LS3SJ / LS4SJ – technical datasheet6 sizes · construction, technical data, approvalsXLSXLS2SJ / LS3SJ / LS4SJ 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.

How do LS2SJ, LS3SJ and LS4SJ differ from single-pair LSTCJU or watertight LSTCJX shipboard thermocouple cables?
LS2SJ (2-pair), LS3SJ (3-pair) and LS4SJ (4-pair) under MIL-DTL-24643/42 are multi-pair Type J thermocouple extension trunk cables with individually braided-shielded 20 AWG pairs. Single-pair shipboard drops use MIL-DTL-24643/55 (LSTCJU / LSTCTU) or watertight MIL-DTL-24643/56 (LSTCJX / LSTCKX / LSTCTX).
What is the difference between the -UN and -AN suffixes on M24643/42 part numbers?
'-UN' designates an unarmoured, non-watertight low-smoke cable for internal raceways and enclosed consoles. '-AN' adds an exterior braided Aluminum alloy 5056 armour over the LSZH jacket for mechanical protection in machinery rooms.
How do you identify the positive and negative conductors on a MIL-DTL-24643/42 Type J pair?
Per ANSI MC96.1 / ASTM E230, the positive Iron (JP) leg is insulated in White (and is magnetic to a hand magnet), while the negative Constantan (JN) leg is insulated in Red.
Why is each pair jacketed over its individual tinned-copper braid shield?
Thermocouple shields must be grounded at only one point (typically at the sensor or reference junction) to avoid circulating 60 Hz / 400 Hz hull currents. Extruding an insulating jacket over each braided pair prevents adjacent shields from touching inside the cable.

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LS2SJ / LS3SJ / LS4SJ MIL-DTL-24643

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