
3M Cold Shrink Tubes – EPDM Rubber
Electrical Submersible Pump (ESP)
Cable RepairsÂ
Electrical Submersible Pumps (ESP) are used to lift oil from a production well, so it is important that the supply cables are reliable and operate safely for an extended service life in the harshest offshore downhole environments.
The ESP cable used to transmit power and sensor outputs to and from the surface is a key component in an ESP installation. The cable must withstand mechanical abrasion, corrosion, high temperature and pressure and should be available in a variety of cross-sections and configurations so the space the cable takes in the well bore is optimized and it can be installed or retrieved easily.
Schlumberger RedaMAX 400 is a 5kV-8kV high voltage cable designed specifically for use with electrical submersible pumps, however the cable can also be used within onshore and offshore gassy wells and other high temperature applications in the oil and gas industry with ESP systems installed.
The benefits associated with the RedaMAX 400 ESP submersible pump cable include lower life cycle cost, long insulation life and longer ESP system life – with EPDM insulation-jacket compounds, galvanised steel armor and lead barrier the power cables temperature rating up to 232°C provides consistent delivery of electrical power to downhole equipment.
The ESP cable is available in three options including the common round profile option but also a flat cable version – in this post we provide information about cold shrink tubes for use with ESP cable repair applications.

RedaMAX 400 ESP Cable Specifications
The 3 versions of the Schlumberger RedaMAX 400 cables are available in different voltages :
- 4kV Flat Cable | Lead Barrier | Galvanised Steel Armor | EPDM Cable Jacket
- 4kV Round Cable | Lead Barrier | Galvanised Steel Armor | EPDM Cable Jacket
- 5kV Flat Cable | Lead Barrier | Galvanised Steel Armor | EPDM Cable Jacket
- 5kV Round Cable | Lead Barrier | Galvanised Steel Armor | EPDM Cable Jacket
- 8kV Round Cable | Lead Barrier | Galvanised Steel Armor | EPDM Cable Jacket
Cables Nomenclature Guide ➡

Cold Shrink Cable Repair Tubes
Power Cables Portfolio for REDA ESP Systems
Cable Family |
Cable Application |
Cable Construction |
REDA MAX 250 |
Low temperature, low gas |
PPEO, PP, PTB, POTB |
REDA MAX 400 |
High temperature, moderate gas |
EE, ETBE |
REDA Lead |
High temperature, gassy, corrosive |
ELBE, ELB, EHLTB |
READ Lead 8kV |
Deep water, subsea, high temperature, high horsepower |
ELBE, ELB, EHLTB, SESLTBE |
3M EPDM Rubber Cold Shrink Tubes
When repairing Schlumberger RedaMAX ESP Power Cables it is advisable to use the 3M EPDM Connector Insulators 8420 Series Cold Shrink Tubes.
This insulating tube forms part of the wider range of cold shrink tubes available from 3M Electrical and distributed by Thorne & Derrick.
There are many benefits of using cold shrink technology :
- Simple installation, requiring no tools or heat shrink torches – ideal for “explosive atmospheres” and hazardous area locations
- Can accommodate a wide range of LV HV cables – Cold Shrink is a versatile cable repair solution
- Good thermal stability and tight seal around the cable sheath jacket profile
- Fungus, acid and alkali resistant for onshore and offshore aggressive applications
- Excellent wet electrical properties for offshore installations
3M EPDM cold shrink tube forms a cable sheath repair when it is applied around the electrical connector and the cable itself.
3M Connector Insulators 8420 Series Cold Shrink Application

Insulation of inline conductor transition connectors
The insulating cold shrink tube is made from EDPM rubber containing no chlorides and six diameter sizes will cover a full range of 1000 volt cables.
In addition to ESP cables, the 3MÂ 8420 Series EPDM tubes can be used in other applications including dig-in and cable sheath repairs, insulation of secondary cable splices and primary electrical insulation for all solid dielectric (rubber and plastic) insulated wire and cable splices rated to 1000Â volts.
3M Cold Shrink EPDM Tubes
Connector Insulator 8420 Series
Selection Table
3M Cold Shrink Tubes Part No |
Suit Conductor Sizes AWG & Kcmil |
Min Diameter (mm) |
Max Diameter (mm) |
Length (mm) |
8423-6 |
6 – 4 |
7.8 |
14.3 |
152 |
8425-7 |
2 – 1/0 |
9.9 |
17.8 |
178 |
8425-8 |
2 – 1/0 |
10.2 |
20.8 |
203 |
8426-11 |
2/0 – 250 |
13.0 |
25.4 |
279 |
8426-9 |
2/0 – 250 |
13.0 |
25.4 |
229 |
8427-12 |
250 – 400 |
17.5 |
33.0 |
305 |
8427-16 |
250 – 400 |
17.5 |
33.0 |
406 |
8427-6 |
+++ |
17.5 |
33.0 |
152 |
8428-12 |
450 – 800 |
24.0 |
49.3 |
305 |
8428-18 |
450 – 800 |
24.0 |
49.3 |
457 |
8428-24 |
450 – 800 |
24.0 |
49.3 |
609 |
8428-6 |
+++ |
24.0 |
49.3 |
152 |
8429-12 |
900 -1000 |
32.2 |
67.8 |
305 |
8429-18 |
900 – 1000 |
32.2 |
67.8 |
457 |
8429-6 |
+++ |
32.2 |
67.8 |
229 |
8429-9 |
+++ |
32.2 |
67.8 |
152 |
8430-18 |
1250-2000 |
42.6 |
93.7 |
457 |
8430-9 |
+++ |
42.6 |
93.7 |
229 |
8430-18 |
1250-2000 |
42.6 |
93.7 |
457 |
8430-24 |
1250-2000 |
42.6 |
93.7 |
610 |
+++ Primary Cold Shrink Use: Sealing cable lugs and terminal barrels, conduit couplings and conduit-to cable breakouts
LV Cable Joints (Low Voltage Cables)
Thorne & Derrick stock and distribute LV Joints in Cold Shrink, Heat Shrink or Resin Cast technologies – multicore and multi-pair cable joints are available for immediate backfill and energisation of Low Voltage power, control and instrumentation cables 600V/1000V 3.3kV.
Complete range of LV Cable Accessories ➡
Cable Breakouts | Cable Caps | Cable Lugs | Cable Cleats | Cable Trough | Cable Duct | Feeder Pillars | for 11kV/33kV/66kV networks see MV HV Joints & Terminations