Page 1 of 4
Cold Shrink EPDM Tubes
Connector Insulators 8420 Series
Data Sheet
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Product Description
3M Brand PST Cold Shrink Connector Insulators are a series of open-ended, tubular rubber sleeves, which are factory
expanded and assembled onto a removable core. They are supplied for field installation in this pre-stretched condition.
The core is removed after the tube has been positioned for installation over an inline connection, terminal lug, etc.,
allowing the tube to shrink and form a waterproof seal. The insulating tube is made of EPDM rubber, which contains no
chlorides or sulphurs. Six diameter sizes will cover a range of 1000 volt cables, copper and aluminium conductors.
PST features are:
•
Simple installation, requires only workman’s hands
•
Accommodates a wide range of cable sizes
•
No torches or heat required
•
Good thermal stability
•
Seals tight, retains its resiliency and pressure even after prolonged years of ageing and exposure
•
Excellent wet electrical properties
•
Improved tough rubber formulation to withstand rough backfilling
•
Waterproof. Meets water seal requirements of NEMA Pub. No. PP-C1
•
Resists fungus
•
Resists acids and alkalis
•
Resists ozone and ultraviolet light
Applications
•
Primary electrical insulation for all solid dielectric (rubber and plastic) insulated wire and cable splices rated to
1000 volts
•
Suitable for direct burial or submersion
•
For indoor, outdoor, or overhead use
•
Physical protection and moisture sealing for high-voltage, air-insulated connectors and lugs such as spacer cable
and lug connections to bus bar
•
Insulation of secondary splices copper or aluminium conductors
•
Relocation of service
•
Dig-in repairs
•
Sheath repairs
•
Insulation of inline conductor transition connectors (see Figure 1)
8426 PST Cold Shrink
Connector Insulator
70mm2
Connector
120mm2
Figure 1
_________________________________________________________________________________________
Electrical Markets Division
3M United Kingdom PLC
Sales Office
PO Box 393
Bedford MK41 0YE
Telephone: 0870 609 4639
Fax: 01234 229 433
3M Ireland Ltd
Sales Office
The Iveagh Building, The Park,
Carrickmines, Dublin 18, Ireland
Telephone: (01) 800 812 732
Fax: 353 1 280 3509
3M United Kingdom PLC
Head Office
3M Centre, Cain Road
Bracknell, Berkshire RG12 8HT
Telephone: 01344 858 000
Fax: 01344 858 758
Page 2 of 4
Cold Shrink EPDM Tubes
Connector Insulators 8420 Series
Data Sheet
__________________________________________________________________________________
PST Selection Table
8423-6
8425-8
8426-9
8426-11
8427-6
8427-12
8427-16
8428-6
8428-12
8428-18
8428-24
8429-4
8429-6
8429-9
8429-12
8429-18
8429-24
8430-9
8430-18
8430-24
Min. diameter (mm)
7.8
10.2
13.0
13.0
17.5
17.5
17.5
24.0
24.0
24.0
24.0
32.2
32.2
32.2
32.2
32.2
32.2
42.6
42.6
42.6
Data: Physical & Electrical Properties
Typical Physical & Electrical Properties
Physical Properties
Test Method
Colour
100% Modulus ASTM D 412
300% Modulus ASTM D 412-75
Ultimate Tensile ASTM D 412-75 Original
Ultimate Elongation ASTM D 412-75 Original
Die C Tear ASTM D 624C-73 Original
Fungus Resistance ASTM G-21 28 days exposure
Shore A Hardness ASTM D 2240-75
Permanent Set 3M test method @ 250% strain 5 minute
recovery
Moisture Absorption
24hrs 90°C H2O
7 days 90°C H2O
Electrical Properties
Dielectric Strength ASTM D 149-75 Original @ 1.78mm
7 days in H2O at 90°C
Dielectric Constant Original
7 days 90°C H2O
Max. diameter (mm)
14.3
20.8
25.4
25.4
33.0
33.0
33.0
49.3
49.3
49.3
49.3
67.8
67.8
67.8
67.8
67.8
67.8
93.7
93.7
93.7
Length (mm)
152
203
229
279
152
305
406
152
305
457
609
100
152
229
305
457
610
229
457
610
Typical Value
Black
1.17 Mpa
4.7 Mpa
11.6 Mpa
635%
38.5KN/m
No growth
48
RT 8.8% 4.4°C (40°F) 14.6%
Wt. Gain
1.3%
3.2%
19.1 MV/m
18.1MV/m
5.0
5.6
Specifications
Product
Splicing of all 1000 volts or less inline power cables from 6mm2 to 500mm2 shall be done in accordance with the
_________________________________________________________________________________________
Electrical Markets Division
3M United Kingdom PLC
Sales Office
PO Box 393
Bedford MK41 0YE
Telephone: 0870 609 4639
Fax: 01234 229 433
3M Ireland Ltd
Sales Office
The Iveagh Building, The Park,
Carrickmines, Dublin 18, Ireland
Telephone: (01) 800 812 732
Fax: 353 1 280 3509
3M United Kingdom PLC
Head Office
3M Centre, Cain Road
Bracknell, Berkshire RG12 8HT
Telephone: 01344 858 000
Fax: 01344 858 758
Page 3 of 4
Cold Shrink EPDM Tubes
Connector Insulators 8420 Series
Data Sheet
__________________________________________________________________________________
instructions provided with 3M Brand PST Cold Shrink Connector Insulators.
Engineering/Architectural
The connector insulator must be capable of operation at emergency overload cable temperatures of 130°C. It must be
usable without additional covering or adhesive, both indoors and outdoors, in overhead, direct buried or submersed
applications, on cables rated up to 1000 volts. It must be applied without additional heat or flame and, when applied
according to the manufacturer’s directions, but immediately energizable. It must not be adversely affected by moisture,
mild acids or alkalis, ozone or ultraviolet light. It must be compatible with all rubber or plastic insulated 1000 volt cables.
It must conform to the requirements of ANSI C119.1 1974, appropriate sections of Western Underground Guide 2.14 and
UL 486D. It must have been accepted by the US Dept of Agriculture, Rural Electrification Administration, for both
submersible and aerial application.
Performance Tests
The characteristic which is vital to the performance of the PST is permanent set. Permanent set is defined as “the
percentage of the original stretched deformation not recovered in a given period of time after the deforming force (core)
has been removed”. Because the PST tube has not been allowed to return to its original ID by the cable, a live rubber
force exists between the cable insulation and the PST tube.
The 8420 series tubes are installed on the core at approximately 250% stretch. The permanent set test is done in the
tension mode and reflects the elastic memory property of the material. Field experience combined with laboratory test data
has shown that our EPDM PST/Cold Shrink™ compounds exhibit excellent long-term elastic memory characteristics.
Moisture, Heat and Seal Tests
3M Brand Connector Insulators meet or exceed the test requirements of UL486D and ANSI C119.1.
Test Sequence.
1. 24 hours in room temperature water (30cm deep).
2. Insulation resistance at dc (500 to 1000V), 1 minute.
3. Dielectric ac withstand, 1 minute at 2200V.
4. Heat at 90°C (±5°C) for 72 hours.
5. Flex test: 10 cycles for 90° right and 90° left.
6. Twist test: twist 15° clockwise and then 15° counter-clockwise from centre 5 times.
7. Water immersion as in Step 1.
8. Insulation resistance as in Step 2.
9. Cold temp. 4 hours at –18°C ± 5°C. Bend and twist per Steps 5. and 6. at temp.
10. Flex per Step 5.
11. Twist per Step 6.
12. Water immersion as in Step 1.
13. Insulation resistance as in Step 2.
14. Current cycle and water submersion test:
a) Heat conductor with current to 90°C for 1 hour.
b) De-energize.
c) Plunge in 25°C (± 5°C) water within 3 minutes of Step b) for ½ hour minimum.
d) Repeat Steps a), b) and c), 25 times.
e) Measure insulation resistance per Step 2.
f) Repeat Steps a), b) and c), 25 times.
g) Dielectric test as in Step 3.
15. Dielectric withstand as in Step 3.
16. Leakage current in water 600V 60hz. 2.5mA max. leakage.
PSTs will seal within 5 minutes at –1°C even on the absolute minimum cable size. Thus, warming with the hands is not
necessary, even below freezing.
_________________________________________________________________________________________
Electrical Markets Division
3M United Kingdom PLC
Sales Office
PO Box 393
Bedford MK41 0YE
Telephone: 0870 609 4639
Fax: 01234 229 433
3M Ireland Ltd
Sales Office
The Iveagh Building, The Park,
Carrickmines, Dublin 18, Ireland
Telephone: (01) 800 812 732
Fax: 353 1 280 3509
3M United Kingdom PLC
Head Office
3M Centre, Cain Road
Bracknell, Berkshire RG12 8HT
Telephone: 01344 858 000
Fax: 01344 858 758
Page 4 of 4
Cold Shrink EPDM Tubes
Connector Insulators 8420 Series
Data Sheet
__________________________________________________________________________________
Resistance to UV
Samples were mounted 50cm from two UA-3 type GC Brand bulbs. The samples were examined after 70 hours. No
cracks were observed.
Chemical Resistance
Samples of rubber were immersed in solutions for 30 days at room temperature and the physical characteristics were
measured (Figure 2).
100%
Modulus
100
81
10% Sulfuric Acid (H2SO4)
10% Sodium Hydroxide (NaOH)
Figure 2
% Retention
Breaking
Strength
90
78
Breaking
Elongation
95
104
Installation Techniques
1. Remove loose core end from cut and welded end of PST.
2. Slide PST assembly onto cable and install connector (figure 3).
3. Remove defects from surface of cable in seal areas.
4. Hold PST assembly and cable in proper position in one hand and unwind core in counter-clockwise direction with the
other hand (figure 4).
‘PST’
Insulator
Weld
Marker
40mm
Slide ‘PST’ over connector to edge of marker
Figure 3
Figure 4
Maintenance
Components of 3M PST Connector Insulators are stable under normal storage conditions. They are not impaired by
freezing or overheating due to the ambient temperatures found in storage or shipping. Normal storage and stock rotation
are recommended.
Availability
3M PST Cold Shrink Connector Insulators are available in 8 diameter sizes covering an application range of 8 to 94mm.
They are available from your authorised 3M electrical distributor.
Important Notice
Technical information provided by 3M is based on experience and/or tests believed to be reliable, but their accuracy is not guaranteed and the results may not be relevant to
every user’s application. For this reason 3M does not accept responsibility or liability, direct or consequential, arising from reliance upon any information provided and the
user should determine the suitability of the products for their intended use. Nothing in this statement will be deemed to exclude or restrict 3M’s liability for death or personal
injury arising from its negligence. All questions of liability relating to 3M products are governed by the seller’s terms of sale subject where applicable to the prevailing law. If
any goods supplied or processed by or on behalf of 3M prove on inspection to be defective in material or workmanship, 3M will (at its option) replace the same or refund to
the Buyer the price paid for the goods or services. Except as set out above, all warranties and conditions, whether express or implied, statutory or otherwise are excluded to
the fullest extent permissible at law. 3M is a trademark of the 3M Company. Printed in the UK. © 3M United Kingdom PLC,. Issue 2 05/11/09
_________________________________________________________________________________________
Electrical Markets Division
3M United Kingdom PLC
Sales Office
PO Box 393
Bedford MK41 0YE
Telephone: 0870 609 4639
Fax: 01234 229 433
3M Ireland Ltd
Sales Office
The Iveagh Building, The Park,
Carrickmines, Dublin 18, Ireland
Telephone: (01) 800 812 732
Fax: 353 1 280 3509
3M United Kingdom PLC
Head Office
3M Centre, Cain Road
Bracknell, Berkshire RG12 8HT
Telephone: 01344 858 000
Fax: 01344 858 758
