Size and weight
Spec 55 wire provides one of the most
comprehensive wiring product ranges for
aerospace users, with a wide choice of
conductor sizes and insulation wall thickness.
The dual wall airframe wire has an insulation
wall thickness of either 0.2mm or 0.25 mm for
robustness in unprotected harnesses and has
excellent wire to wire abrasion properties. The
single wall equipment wire has a 0.15 mm wall
thickness for use inside equipment and
protected harnesses. For high density
interconnect wiring, the 450 volt 55M041X
series of equipment wire has a nominal 0.1 mm
wall and provides considerable weight and size
savings over other comparable wires.
The excellent flexibility and low resilience
makes Spec 55 the ideal wire to install, both in
new aircraft and equipment and for
maintenance purposes. The wire is easily
stripped with conventional tooling. The
insulation is readily marked by hot stamp, ink
jet or laser, and can be potted without pre-
For full descriptions of the appropriate tools
see separate wire handling guide.
Temperature rating (Tin plated conductor)
(Silver or nickel plated conductor)
Scrape abrasion (BS 3G233)
Flexing endurance (Boeing BSS 7324)
Tensile strength + core elongation
Tensile strength + total elongation
Notch propagation BS 3G230 0.05 mm notch
Solder iron resistance (370°C, 1 minute)
Solderability - Tin plated copper conductor
BS 3G233 conditions
Long term water resistance
Permittivity 1 KHz (ASTM D150)
Dissipation factor (ASTM D150)
-65°C to +150°C
-65°C to +200°C
200°C, 10000 h
>100 cycles at 150°C
600 V, 450V
(Airframe wire only) 35 N/mm2, 125%
(All primary wire) 35 N/mm2, 75%
<0.8 secs to wet
Will not hydrolyse
Spec 55 wire and cable is rated for continuous
operation from -65°C to +200°C and for short
periods at temperatures as high as 400°C.
Radiation crosslinking of the Spec 55 insulation
significantly improves the following
mechanical characteristics; scrape (sharp
edges), cross wire abrasion, cut-through
resistance and creep resistance.
Solder iron/Overload resistance
Radiation crosslinking ensures that the
insulation does not melt at high temperature.
As a result Spec 55 wire is resistant to hot
solder irons and current overloads which would
melt most thermoplastic insulations.
Spec 55 is unaffected by all commonly used
chemicals, eg. fuels, hydraulic fluids, defluxing
agents, cleaners, coolants and de-icers. It also
shows excellent resistance to weathering
(UV, ozone, pollutants, water).
Spec 55 is available in special versions suitable
for use in outer space meeting both ESA and
NASA requirements for outgassing.
Special additives increase the flame retardance
of Spec 55 compared to unirradiated ETFE so
that it meets the latest high performance tests,
eg. BS 3G230 vertical test FAR 25.
Electrical arc tracking resistance
Spec 55 insulation demonstrates resistance to
arc tracking under both wet and dry conditions
at aircraft system voltages.