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3M™ Cold Shrink Silicone Rubber
Connector Insulators 8440 Series
Product
Description
3M™ Cold Shrink Connector Insulators 8440 Series are open-ended, silicone rubber, tubular
sleeves. The sleeves are factory expanded an d asse mbled on a removable supporting plasti c core.
Each rubber assembly is supplied for field installation in this pre-stretched condition. As the core is
unwound, the insulating sleeve shrinks to form a tight seal. Three sizes of Cold Shrink Insulators
cover terminal lug barrels and inline connectors. Collectively, the insulators h ave an application
range of 0.35" (8,86 mm) to 0.95" (24,13 mm) for in stallations on #6 AWG to 3/0 AWG.
Features Simple installation requires only workman's hands
No tools required
No heat required for installation
Seals tight, retains its resiliency and pressure even after prolonged years of aging and exposure
Resists moisture
Wide range, size accommodation
Resists acids and alkalies
Resists ozone and ultraviolet light
Resists fluid splashes
Resists fire - will not support flame
Operating temperature range -66ºF to 500ºF ( -55ºC to 260ºC)
Data Sheet May 2014
Applications
Primary electrical insulation for all solid diele ctric (rubber and plastic) insulated wire and cable
splices rated to 1000 volts
Electrical Aircraft cables
For indoor and outdoor use, in cable tray or overhead applications
Top moisture sealing for medium voltage, air insul ated connectors and lugs
Insulation of secondary splices, copper and aluminum conductors
Sheath repairs
Insulation of inline conductor transition conne ctors
3M™ Cold Shrink Silicone Rubber Connector Insulators 8440 Series
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3/8”
(9,5 mm)
min
Typical
Physical
Properties
Typical
Electrical
Properties
Not for specifications. Values are typical, not to be considered mini mum or maximum.
Properties measured at room temperature 73°F (23° C) unless otherwise stated.
Physical Property (Test Method) Typical Value US unit (metric)
Colo
r
Gray
100% Modulus (ASTM D 412) 180 psi (1,24 MPa)
Ultimate Tensile (ASTM D 412) 1240 psi (8,55 MPa)
Die B Tear (ASTM D 624B) 185 psi (1,28 MPa)
Hardness (ASTM D 2240) 48 Shore A
Specific Gravity 1.23
Electrical Property (Test Method) Typical Value US unit (metric)
Dielectric Strength
(ASTM D 149) @ 1,78 mm thickness 554 V/mil (21,8 mV/m)
Dielectric Strength
168 hours in H2O @ 194°F (190°C) 543 V/mil (21,4 mV/m)
Part
Number
Cable Range Application Range
Inches (mm) Dimensions
Inches (mm)
AWG Min. Dia.
for Seal
Max. Dia.
Insulator
Covers
[A]
Length [B]
Core I.D.
8443-2 6 - 2 0.30 (7,6) 0.560
(14,22) 1.4 (36) 0.68 (17,3)
8443-6.5 5.2 (132)
8445-2.5 2 - 1/0 0.37 (9,4) 0.720
(18,29) 1.7 (43) 0.84 (21,3)
8445-7.5 6.2 (158)
8447-3.2 1/0 - 3/0 0.49 (12,4) 0.950
(24,13) 2.3 (57) 1.07 (27,2)
8447-8 6.8 (172)
Table 1
Plastic Supporting Core
Loose Core End
Expanded Silicone R ubber Tube
A
B
3M™ Cold Shrink Silicone Rubber Connector Insulators 8440 Series
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Product
Specifications
Exposed metallic connectors joining power cable conductors rated 1000 volts or less shall be
covered with 3M Cold Shrink Silicone Tubular Rubber Insulation 8440 Series.
The inline connections shall be insulated in accordance with the instructions provided with the
3M™ Cold Shrink Connector Insulator 8443-6, 8445-7.5, and 8447-8. The connecting barrel
portion of terminal lugs shall be insulated in accordance with the instructions provided with the
3M™ Cold Shrink Connector Insulators 8443-2, 8445-2.5, and 8447-3.2.
Engineering and
Architectural
Specifications
A silicone rubber cold shrink connector insulator must be capable of normal operation through a
temperature range of 66˚F/ -55˚C to 500˚F/260˚C. It must be usable without additional covering or
adhesive both indoors and outdoors, in cable tray or overhead applications on cable s rated u p to
1000V. It must be applied without additional heat or flame and, when applied according to
manufacturer's directions, be immediately energizable. It must not support flame or be adversely
affected by moisture, mild acids or alkalies, ozone or ultraviolet light. It must provide resistance to
aircraft fluids and be compatible with all rubber and plastic insulated power cables.
Performance
Tests
Flammability Test
The test for flammability of the 3M Cold Shrink Insulators 8440 Series was conducted with
specimens positioned both vertically and horizontally per specifi cation BSS 7230. The silicone
rubber insulation passed the Flammability Test of BSS 7230 without supp orting a flame. In addition,
these insulators were also subjected to a gas flame test as outlined in paragraph 4.4.15 of MIL-C-
24643A and met the passing criteria a s specified. No fuse was blown
during the one hour flame exposure.
Humid Environment
Tests to verify electrical integrity through conditions of high humidity were run per Mil Standard
202- Method B. The test duration was 10 days at 104˚F/40˚C and 95% RH. Typical test values are
found in Table 2.
Test Insulation
Resistance Withstand Result
Before 3.0 x
10
12
2500 V-rms
Pass
After 2.5 x
10
12
2500 V-rms
Pass
Table 2
Ultraviolet Resistance
After 1000 hours of testing in a Weather-O-Mete r a cco rding to Specifications ASTM D750 and
ASTM G23, the silicone rubber insulation did not exhibit crazing, cracking or change in surface
appearance.
Thermal Shock
Assembled units from the fluid resista nce test were used for the thermal shock evaluation. The
units were subjected to 15 cycles of the followin g thermal shock sequence:
1. 30 minutes at -66˚F/ -55˚C
2. 5 minutes at 74 ˚F/23˚C
3. 30 minutes at 500˚F/260˚C
4. 5 minutes at 74 ˚F/23˚C
The insulation resistance values and results of test are found in Table 3.
3M™ Cold Shrink Silicone Rubber Connector Insulators 8440 Series
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Performance
Tests
(continued)
Altitude
Electrical integrity at high at high altitudes was determined by testin g to Mil Standard 1344A, Test
method 1004.1. Typical test values are found in Ta ble 4.
Altitude Insulation
Resistance Withstand Result
50,000 1.0 x 10 11 ohms 2500 V-rms
Pass
70,000 1.8 x 10 12 ohms 2500 V-rms
Pass
Table 4
Heat Aging
Installed silicone rubber insulators were subjected to an eight hour heat aging test at 500˚F/260˚C.
Other units were subjected to 401˚F/205˚C for 30 days. The silicone rubber rem ained resilient and
showed no sign of deterioration.
Fluid Resistance
To determine the effect of a fluid splash on insulated connected a ssemblies, the units were
subjected to ten cycles of the followi ng test sequence:
1. One minute fluid soak
2. 24 hour , 74˚F/23˚C ambient dry
3. Insulation resistance measurement
4. 2.4 kV-rms withstand
Results from the fluid resistance test are found in table 5.
Fluid
Test Insulation
Resistance Withstand Result
Monsanto L.D. Before
After 1.5 x 1013 ohms
1.0 x 1012 ohms 2500 V-rms
2500 V-rms Pass
Pass
Jet A Before
After 7.0 x 1012 ohms
1.7 x 1012 ohms 2500 V-rms
2500 V-rms Pass
Pass
MIL-L-7808 Before
After 3.5 x 1012 ohms
6.5 x 1012 ohms 2500 V-rms
2500 V-rms Pass
Pass
MIL-L-23699 Before
After 8.0 x 1012 ohms
3.5 x 1012 ohms 2500 V-rms
2500 V-rms Pass
Pass
5% Saline Before
After 9.0 x 1012 ohms
6.5 x 1012 ohms 2500 V-rms
2500 V-rms Pass
Pass
Fluid Splash Test Insulation Resistance/2500 V-rms Wi th stand
Fluid Monsanto L.D . Jet
A
MIL-L-7808 MIL-L-23699 5% Saline
Initial 1.5 x 1013/Pass 7.2 x 1012/Pass 3.5 x 1012
/
Pass 8.0 x 1012/Pass 9.0 x 1012/Pass
1
2
3.0 x 109 ohms
1.2 x 109 ohms 2.0 x 1012 ohms
1.2 x 1012 ohms 8.0 x 1012 ohms
2.0 x 1012 ohms 2.5 x 1012 ohms
5.0 x 1012 ohms 3.5 x 1012 ohms
5.0 x 1012 ohms
3
4
4.0 x 107 ohms
1.8 x 107 ohms 1.2 x 1012 ohms
8.0 x 1011 ohms 2.5 x 1012 ohms
3.0 x 1012 ohms 4.0 x 1012 ohms
3.0 x 1012 ohms 3.5 x 1012 ohms
4.0 x 1012 ohms
5
6
8.0 x 106 ohms
6.0 x 106 ohms 3.0 x 1011 ohms
2.0 x 1011 ohms 2.0 x 1012 ohms
1.8 x 1012 ohms 2.5 x 1012 ohms
2.0 x 1012 ohms 6.0 x 1012 ohms
7.0 x 1012 ohms
7
8
5.0 x 106 ohms
4.0 x 106 ohms 1.8 x 1011 ohms
1.0 x 1011 ohms 1.0 x 1012 ohms
1.0 x 1011 ohms 2.5 x 1012 ohms
1.4 x 1012 ohms 9.0 x 1012 ohms
3.0 x 1012 ohms
9
10
4.0 x 106 ohms
3.5 x 106 ohms 1.0 x 1011 ohms
7.0 x 1010 ohms 6.5 x 1011 ohms
5.0 x 1011 ohms 1.0 x 1012 ohms
1.2 x 1012 ohms 3.0 x 1012 ohms
5.0 x 1012 ohms
Table 5
3M™ Cold Shrink Silicone Rubber Connector Insulators 8440 Series
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Maintenance
Components of 3M™ Cold Shrink Silicone Rubber Conne ctor Insulators are stable under no rmal
storage conditions for a period of three years from the date of manu facture. The cold shrink
insulators are not impaired by freezing or overheating due to the ambient temperatures found in
storage or shipping. Normal storage and stock rotation are recommended.
Approximate Installed Weight
Terminal Lug Insulators Inline Connector Insulators
Part No. Weight
oz. (gm) Part No. Weight
oz. (gm)
8443-2 0.123 (3.5) 8443-6.5 0.388 (11.0)
8445-2.5 0.190 (.54) 8445-7.5 0.564 (16.0)
8447-3.2 0.335 (9.5) 8447-8 0.776 (22.0)
Table 6
Shelf Life &
Storage
3M™ Cold Shrink Silicone Rubb er Connector Insulators 8440 Series have a 3-year shelf life from
date of manufacture when stored in a humidity controlled storage (10°C/50°F to 27°C/8 0°F and
<75% relative humidity).
Availability
Please contact your local distributor; av ailable from 3M.com/electrical [Where to Buy] or call
1.800.245.3573.
3M is a trademark of 3M Company.
3M
Electrical Markets Division
6801 River Place Blvd.
Austin, TX 78726-9000
800.245.3573
FAX: 800.245.0329
www.3M.com/electrical
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