O-Route® NEK-606 Offshore Cable Guide | Marine Boys

O-Route® NEK-606 Offshore Cable Guide: Halogen-Free, Mud-Resistant Marine & Offshore Cable Explained

Last updated: July 2026 · Written by Marine Boys / Sea Dragon Marine — ship provisioning & technical store suppliers, Port of Kwinana, Western Australia.

If you're specifying cable for an FPSO, drilling rig, offshore support vessel or platform, you'll almost certainly come across the designation NEK-606 and the brand name O-Route®. This guide breaks down what these cables are, how the code designation system works, and how to choose the right type for your application — based on the O-Route® offshore cable range manufactured by Songhyun TMC (TMC Co., Ltd), South Korea.

What Is O-Route® Cable?

O-Route® is the offshore cable brand of Songhyun TMC (TMC Co., Ltd), a Korean cable manufacturer with over two decades of focus on marine and offshore plant cable solutions. O-Route® cables are halogen-free and mud-resistant, purpose-built for offshore platforms, drilling rigs, FPSOs and other marine installations where fire safety, chemical exposure and mechanical durability are critical.

TMC's certifications include type approvals from ABS, BV, DNV, GL, KR, LR, NK and RINA for shipboard cables, plus ABS, DNV and LR approval specifically for NEK 606 offshore cables, and Gost-R certification for the Russian market. The company has been recognised as a preferred supplier by Hyundai Heavy Industries, Samsung Heavy Industries and DSME.

What Does "NEK-606" Mean?

NEK-606(2016) is the Norwegian offshore cable standard developed specifically for the demanding conditions found on oil and gas installations — drilling mud exposure, hydrocarbon contact, fire risk and extreme cold. O-Route® cables are designed to NEK-606(2016) in conjunction with the IEC 60092 series:

• IEC 60092-350 – General requirements for construction and test methods of shipboard and offshore cables

• IEC 60092-353 – Single and multicore power cables

• IEC 60092-354 – Single and multicore power cables with extruded solid insulation for rated voltages 6 kV to 30 kV

• IEC 60092-376 – Instrumentation and control cables (250 V)

Because these cables must survive both a fire event and ongoing contact with drilling mud, oils and chemicals, NEK-606 testing goes well beyond a standard shipboard cable spec — it's the reason offshore cable typically costs more and is sourced from specialist manufacturers rather than general shipboard cable suppliers.

O-Route® Cable Range at a Glance

Cable GroupTypical DesignationsVoltageHV Power CableRFOU, RFBU, RFCU3.6/6kV, 6/10kV, 8.7/15kVLV Power & Lighting CableRU, RFOU, RFCU, RFBU, BU, BFOU, BFCU, BFBU0.6/1kVInstrumentation & Communication CableRU(c/i/i&c), RFOU(c/i/i&c), BU(c/i/i&c), BFOU(c/i/i&c)250VVFD (Variable Frequency Drive) CableRFOU(VFD), BFOU(VFD), FX-RFOU(VFD), FX-BFOU(VFD)0.6/1kV (1.8/3kV)Earthing & Bonding WireUX, FX-UX0.6/1kV

How to Read the O-Route® Code Designation

Once you understand the letter code, you can decode almost any O-Route® part number at a glance. Take 0.6/1kV BFOU as a worked example:

• B – Fire-resisting layer (mica/glass tape) + EPR insulation

• F – Halogen-free inner covering/compound

• O – Armour: tinned annealed copper wire braid (C = galvanized steel wire; B = bronze wire)

• U – SHF2 thermoset outer sheath (option: NEK 606 mud/oil resistant compound)

Other core letters you'll see: R = EPR insulation only (flame retardant, not fire resistant); (i) = individual screen; (c) = collective screen; (i&c) = both; VFD = variable frequency AC motor drive cable.

Sheath / Mud & Oil Resistance Marking

MarkingMeaningNo markingMinimum NEK 606 requirement (Category a)EEnhanced oil resistant – Category bMEnhanced oil resistant (Cat. b) + Mud resistant – Category cHEnhanced oil resistant (Cat. b) + Hydraulic/gear oil resistant – Category dH-MCategories b, c and d combined (highest chemical resistance)

Category c (mud resistance) is tested against calcium bromide brine and EDC 95-11 base oil at 70°C for 56 days, with tensile strength, elongation, volume swelling and weight change all held within tight tolerances — this is the specific property that distinguishes true "mud-resistant" offshore cable from standard marine cable.

Popular O-Route® Type Codes

DesignationCable Type Code0.6/1kV RUP1110.6/1kV RFOUP1010.6/1kV BUP1100.6/1kV BFOUP1050.6/1kV UXP1083.6/6kV RFOUP1026/10kV RFOUP1038.7/15kV RFOUP104250V RU(c)S106250V RU(i)S105250V RFOU(c)S102250V RFOU(i)S101250V BFOU(c)S104250V BFOU(i)S103

Key Performance Standards

• Flame retardant: IEC 60332-1 and IEC 60332-3 Category A

• Fire resistant (BU/BFOU types): IEC 60331-21 (90 min), IEC 60331-1/-2 (120 min)

• Halogen content: IEC 60754-1, ≤ 0.5%

• Cold bend / impact: CSA C22.2 No. 2556 or IEC 60092-350 Annex E, Method 1 (−40°C / −35°C)

• Smoke light transmittance: IEC 61034, ≥ 60%

• Sunlight (UV) resistance: UL 1581

• Mud / oil resistance: NEK 606, Categories a–d

Where Is O-Route® Cable Used?

O-Route® halogen-free, mud-resistant cable is specified for drillships, semi-submersibles, FPSOs, jack-up rigs and fixed offshore platforms — anywhere cable is exposed to drilling mud, hydraulic fluid, hydrocarbons, salt spray and fire risk simultaneously. Typical applications include:

• Topside and drill floor power distribution (HV/LV power cable)

• Lighting circuits in hazardous and non-hazardous areas

• Instrumentation, control and SCADA wiring on process modules

• VFD-driven motor circuits (mud pumps, thrusters, drawworks)

• Hull and structure earthing/bonding

Sourcing O-Route® Cable in Western Australia

Sea Dragon Marine and Marine Boys supply Songhyun TMC / O-Route® offshore cable to the Western Australian offshore and marine sector via the Port of Kwinana. We can help you cross-reference NEK-606 cable types against your existing spec, confirm ABS/DNV/LR/BV/GL type approval documentation, and arrange supply for vessel, rig or platform projects.

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Frequently Asked Questions

What does NEK-606 mean on a cable datasheet?

NEK-606 is the Norwegian offshore cable standard (current edition NEK-606:2016) covering halogen-free, mud- and oil-resistant power, instrumentation and control cables for offshore oil and gas installations. It's used alongside IEC 60092-350, -353, -354 and -376.

What is the difference between RFOU and BFOU cable?

Both are 0.6/1kV halogen-free, armoured, mud/oil-resistant offshore cables with EPR insulation. RFOU is flame retardant only. BFOU adds a mica/glass fire-resisting tape layer under the insulation, giving it a fire resistance rating of 90–120 minutes under IEC 60331, in addition to flame retardancy.

What does the "mud resistant" rating actually test for?

Mud resistance (NEK 606 Category c) is verified by immersing the cable sheath in calcium bromide brine at 70°C for 56 days and separately in EDC 95-11 base oil at 70°C for 56 days, then checking that tensile strength, elongation, volume swelling and weight change stay within defined limits. This simulates prolonged contact with oil-based and brine-based drilling fluids.

Is O-Route® cable halogen-free?

Yes. O-Route® cables use halogen-free compounds throughout (insulation, inner covering and sheath), tested to IEC 60754-1 with halogen content below 0.5%, and achieve at least 60% smoke light transmittance under IEC 61034 — important for evacuation visibility in an enclosed offshore module in the event of a fire.

What certifications does O-Route® / Songhyun TMC hold?

Type approvals include ABS, BV, DNV, GL, KR, LR, NK and RINA for shipboard cables, plus ABS, DNV and LR specifically for NEK 606 offshore cables, Gost-R certification, and KEPIC certification for Class 1E cable. TMC is also a recognised excellent/preferred supplier to Hyundai Heavy Industries, Samsung Heavy Industries and DSME.

What's the minimum bend radius for offshore cable?

For unarmoured/unbraided cable up to 1.8/3kV: 4×D (D≤25mm) or 6×D (D>25mm). Metal braid screened or armoured cable: 6×D. Tape screened: 8×D. For 3.6/6kV and above: 12×D (single core) or 9×D (3-core), where D is the overall cable diameter.

O-Route® NEK-606 Offshore Cable Guide | Marine Boys

A practical guide to O-Route® (Songhyun TMC) NEK-606 offshore cable — how to read the code designation, what mud/oil resistance categories a–d mean, and which cable type suits your application. Covers IEC 60092-350/353/354/376 and sourcing in Western Australia.

Read more → https://www.marineboys.com.au/blog/o-route-nek-606-offshore-cable-guide

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