by Chris Dodds - Sales & Marketing Manager Thorne & Derrick
Prior to jointing cables in confined spaces control measures and risk assessment must be undertaken. This picture was taken from outside the manhole once the cable joint was complete – the looped cables were spliced using 3M Scotchcast cable joints to effect a repair to damaged cables in a confined space.
Initially the cable jointers bump test their gas detectors then gas sample the manhole with the lid on for the presence of harmful, flammable or toxic gas.
If all is safe to proceed the jointers remove the lid. Next the working space is vented with forced air while the jointers constantly monitor the confined space with their gas detectors. Access to the manhole is via a wooden ladder with the cable jointers wearing a rescue harness – a tripod and winch are positioned and a gate guard around the manhole is erected to prevent trips, falls or accidents.
The cable is jointed within the manhole to prevent overbending strains on the low voltage cable when fed back into the manhole if jointed at ground level – cable duct seals can be used to prevent the migration of flammable gas or flood waters into the manhole.
The 500kcmil 100 volt rated DC cable circuit is operating at 600 volt – the cable joint/splice utilises 3M Scotch Electrical Tapes with no heat shrink or cold shrink tubing.
3M Scotchcast Cable Joint – Resin & Taped Manhole Cable Splice 600/1000V
3M cable joints use Scotchcast resins for the low voltage jointing of cables with XLPE, EPR, PVC or PILC insulation up to 3.3kV. Resin cable joints specially modified with high performance hydrocarbon resistant, low smoke zero halogen, fire resistant and flame retardant resins are available to withstand harsh operating and environmental conditions in industrial and hazardous area locations. The 3M cable joints are specified throughout ther oil, petrochemical, gas, mines, telecoms, rail and industrial cables are available – suitable for direct burial (underground) or exposed onto cable containment.
Resin Cable Joints – Features & Benefits Of 3M Scotchcast Cable Jointing Systems
Contact Thorne & Derrick to discuss your application for jointing LV cables – we can provide expert technical support, training and specification advice to ensure the correct supply of electrical LV cable joints to suit industrial and hazardous area location cables.
T&D – Main Distributors For 3M Electrical
Should you require any assistance with the selection or specification of cable joints or terminations using 3M Cold Shrink on MV-HV cables please do not hesitate to contact us.
LV ♦ MV ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Installation & Cable Pulling Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
T&D’s Power Blog covers: LV MV HV & EHV Transmission & Distribution, Substations, Switchgear, Cable Jointing & Termination, Cable Fault & Repair, Underground Cables.
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Published 09 Jan 2026
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