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NEK TS 606 specifies the basic requirements for Halogen-Free Low Smoke and Flame Retardant/Fire Resistant, (HFFR-LS) or MUD resistant low and high voltage power, control, lighting, instrumentation, telecommunication and optical fibre cables for offshore installations, and lists Enhanced oil resistance and MUD tests with more demanding requirements than IEC 60092-360:2014.
Generally based on the IEC 60092-350 – 360 and 370 series the purpose of the Technical Specification is to give the end user a selection of cables which meet the requirements for installation on mobile and fixed offshore units.
The predecessor of the Technical Specification was the publication “Recommended Practice for Specification of Cables”, issued by the Norwegian Oil Industry Association” (OLF). The background for that specification was the need of the industry to limit and standardise the number of cable types being used by the offshore industry in the late 1980s. The responsibility for the standard was taken over by the Norwegian Electrotechnical Committee (NEK), and the first edition was issued by NEK as “Norwegian electrotechnical standard” NEK 606 in 1993.
|IEC 60092-350||Electrical installations in ships – Part 350: General construction and test methods of power, control and instrumentation cables for shipboard and offshore applications.|
|IEC 60092-352||Electrical installations in ships – Part 352: Choice and installation of electric cables.|
|IEC 60092-353||Electrical installations in ships – Part 353: Single and multicore cables with extruded solid insulation for rated voltages 1kV and 3kV.|
|IEC 60092-354||Electrical installations in ships – Part 354: Single and three-core power cables with extruded solid insulation for rated voltages 6kV (Um = 7.2kV) up to 30kV (Um = 36kV).|
|IEC 60092-360||Electrical installations in ships – Part 360: Insulating and sheathing materials for shipboard and offshore units, power, control, instrumentation and telecommunication cables. (Replacing IEC 60092 Parts 351 & 359).|
|IEC 60092-376||Electrical installations in ships – Part 376: 150/250V cables for Control and Instrumentation Circuits.|
|IEC 60228||Conductors of insulated cables.|
|IEC 60331-11/21/25||Test for electrical cables under fire conditions – Circuit integrity.|
|IEC 60331-1/2||Test for electrical cables under fire conditions – Circuit integrity.|
|IEC 60332-1-1/2 IEC 60332-2-1/2 IEC 60332-3-10/22/23/24/25||Test for electrical cables under fire conditions. (Flame retardant characteristics for electrical cables).|
|IEC 60445||Basic and safety principles for man-machine interface, marking and identification – identification of equipment terminals, conductor terminations and conductors.|
|IEC 60754-1/2||Test on gases evolved during combustion of electric cables.|
|IEC 60811||Common test methods for insulating and sheathing materials of electric cables.|
|IEC 61034-1/2||Measurement of smoke density of electric cables burning under defined conditions Part 1: Test apparatus Part 2: Test procedure and requirements.|
|HCF||Fire Curve according to EN 1363-2 alternatively ISO 834.|
|JF||Fire test according to ISO 22899-1.|
The cables shall withstand the test specified in IEC 60332-3-10 Part -22, -23, -24 or -25. Single, earth and bonding wires shall withstand the test specified in IEC 60332-1-2 or IEC 60332-2-2.
Fire resistance cables shall be tested according to IEC 60331-1/2 or IEC 60331-11, -21, -25. Test duration: Minimum 120mins without voltage breakdown or conductor rupture.
Fire resistance cables shall be tested according to IEC 60331-1/2 or IEC 60331-11, -21, -25 water spray according to EN 50200 Annex E. Minimum 90min fire plus 15min water spray before breakdown.
All cables shall be halogen-free according to IEC 60754-1/2.
All cables shall be tested for low smoke emission according to IEC 61034-1/2 with minimum 60% light transmittance.
The maximum conductor resistance for 250V instrumentation cables shall be in accordance with IEC 60092-376.
The maximum conductor resisitance for cables with voltage rating 0.6/1kV and above shall be in accordance with IEC 60228 class 2 or class 5.
NEK TS 606 requirements for oil and MUD resistance are more demanding than IEC 60092-360 requirements. These are highlighted in table 1
All SHF2 sheathed cables shall be suitable for an oil production installation.
Minimum required oil resistance
All SHF2 sheathed cables covered by this specification shall fulfil minimum oil resistance according to table 1a.
Oil resistance shall be demonstrated by a test according to IEC 60092-360, SHF2 where test oil IRM902 is specified. Requirements are listed in Table 1a
Similar test shall also be performed with test oil IRM903. Requirements are listed in table 1a.
Optional Enhanced oil resistance
Oil resistance shall be demonstrated by a test according to IEC 60092-360 Annex C.
Test oils shall be IRM902 and IRM903. Requirements are listed in table 1b.
*MUD resistance – (Mandatory requirement for NEK 606 cable descriptions containing SHF2 MUD RESISTANT)
For a cable to be MUD resistant, it must first be qualified as NEK 606 Enhanced oil resistant.
Oil resistance shall be demonstrated by a test according to IEC 60092-360 Annex D. 3.
Test Liquids shall be Calcium Bromide Brine (Water Based) and EDC95-11 (Oil Based). Requirements listed in table 1c.
*When field specific MUD deviates from NEK 606 standard MUD test fluids, (table 1c) special evaluation or testing should be agreed.
0.6/1kV and above shall be in accordance with IEC 60228 class 2 or class 5.
A cable code of two letters, (1. & 4.) or four letters is used to describe the construction.
Additional abbreviation for instrumentation cables:
Collective screen = ©
Individual pair or triple screen = (i)
The interpretation, (per letter) is given in the table below: 0.6/1kV and above shall be in accordance with IEC 60228 class 2 or class 5.
|Materials||1. Letter: Insulation||2. Letter Bedding/inner covering Inner sheath||3. Letter Armour/Screen||4. Letter: Outer Sheath|
|Fire resistant tape + insulation||B||-||-||-|
|Ethylene propylene rubber – EPR||R||-||-||-|
|Cross-linked polyethylene - XLPE||T||-||-||-|
|Fibre – Tight buffered||A||-||-||-|
|Fibre – In loose tube||Q||-||-||-|
|Fire resistant silicone||S||-||-||-|
|Bedding/Inner covering or taping||-||F||-||-|
|Aluminium (laminated to outer jacket)||-||-||L||-|
|Tinned copper wire braid||-||-||o||-|
|Strength member yarn||-||-||A||-|
|Galvanized steel wire braid||-||-||C||-|
|Thermoplastic compound - SHF1||-||-||-||I|
|Thermoset compound – SHF2||-||-||-||U|
|MUD resistant thermoset compound – SHF MUD||-||-||-||U|
|MUD resistant thermoplastic compound||-||-||-||B|
B* = QFCB cables only
For the 250V cables the identification of insulated conductors, (cores) shall be:
Pairs/triples are numbered with numbered tape or by numbers printed directly on the insulated conductors
For 0.6/1kV cables the identification of insulated conductors (cores) shall be in accordance with the CENELEC Harmonization Document HD308S2:
*For certain applications only