Defence Standard 61-12 Part 25 (previously NES525) Multi Pair Individually Screened Special Tratos JBA® Limited Fire Hazard (LFH) Thin Wall Insulated and Sheathed Cable for Military Vessels
DEF 61-12 Part 25 (NES525) cables incorporate LFH thin wall insulation and LFH sheath for reduced levels of smoke and corrosive products in the event of a fire. These cables have been widely adopted as the basis for lightweight Limited Fire Hazard (LFH) cables by the MOD (N) and many other Navies worldwide.
The cores in these cables comply with DEF STAN 61-12 Part 18
This range of individual screened multi pair cables are made from Type 1 pliable type cores.
These cables contain a tinned copper wire braid screen around each pair to confine the electric field and to limit the external electrical influences, each screen is insulated from each other.
The sheath on these cables complies with DEF STAN 61-12 Part 31
These cables are constructed to be compact and circular able to withstand the normal installation hazards encountered during shipbuilding including reeving in, tight bends, glanding, banding and clipping.
These cables are used for both the ships equipment and systems as well as the weapon equipment and systems. The Nato Stock Number (NSN), nominal conductor area, nominal stranding and the conductor formations for these types of cables are shown in DEF STAN 61-12 Part 25, tables 17 and 18 with additional details given in DEF STAN 61-12 part 18.
Each individual cable has a unique NATO Stock Number (NSN), or National Stock Number as it is known in the United States of America (USA).
DEF STAN 61-12 Part 25 Issue 5 (formerly NES 525)
ApplicationDEF 61-12 Part 25 (NES525) cables are typically used for communication, control and instrumentation circuits in Her Majesty surface ships and vessels where electrical screening is required. They are installed and used in both flexing and fixed applications and are suitable for use where fuel, lubricating oils, hydraulic fluids and water are present.
- CONDUCTOR: Stranded tinned annealed copper wire conductors according to Def Stan 61-12 Part 18
- INSULATION: Thin wall Type 1 LFH Tratos Defence Insulation to Defence Standard 61-12 part 25
- CORE ASSEMBLY: Two cores twisted to form a pair
- INDIVIDUAL SCREEN: Tinned annealed copper wire braid
- SCREEN INSULATION: Each pair is insulated by two polyethylene terephthalate tapes applied 50% overlap in opposite directions
- PAIR ASSEMBLY: The required number of individually screened pairs assembled in layers in alternate direction
- OUTER SHEATH: Special Tratos Defence JBA® Black LFH elastomeric compound according to Defence Standard 61-12 part 31 Cable sheath marking + Tratos + year of manufacture + Def Stan 61-12 part 25 + Last seven digits of the NSN number"
FIRE HAZARD TESTS
- Cores in cable – Clause 10 of DEF STAN 61-12 Part 25 Issue 5
- Sheath on multicore cable – DEF STAN 61-12 Part 31
- Complete cable – Flammability – Def Stan 61-12 Part 0 clause 15.12.
- Voltage Rating: 600 Vrms/800 V d.c. (between cores, or between cores and ships structure, or between cores and cable screen)
- Service life 40,000 hours at a continuous conductor temperature of 85°C
- These cables are suitable for use at conductor temperatures from -30°C to +105°C.
- Minimum cable bending radius: Flexing applications 10 x overall cable diameter, fixed applications 4 x overall cable diameter.