Suppliers of Industrial and commercial electric heaters and controls

Tel:  01293 547 361

Industrial and commercial heaters

Tel:  01293 547 361

GP Self-regulating Cable for Gutters and Downpipes

GP Self-regulating cable for gutters and downpipes
  • Stops the accumulation of ice in gutters and downpipes
  • Ensures that rain and melt-water can drain away normally and not cause damage to properties
  • Reduces risks from collapsing gutters and falling icicles.

Range & Prices

The prices shown are list prices and perfectly safe to use for budget purposes. Contact your electrical wholesaler for final prices.

  Model Description List Price
GP-18 Self regulating cable GP-18 Self-regulating cable  (supplied by the metre) £15.50
THK Termination kit (one per circuit) £39.00
THJ Junction Box IP66 6-way terminal block 40A max. £41.00
GP-S Spacer kit GP-S Spacer kit (5 stainless steel spacers and 10 cable ties) £26.00
FST2-EX Frost Thermostat for external use FST2-EX Weatherproof Frost Thermostat £162.00

Technical Specification

GP-18 cable

Voltage: 230V
Nominal output at 0°C in ice water: 36W/m
Nominal output at 0°C in air: 18W/m
Minimum installation temperature: -40°C
Maximum exposure temperature (power on): 60°C
Maximum exposure temperature (power off): 85°C
Minimum bending radius: 35mm
Maximum circuit length: 90m


  • Tin coated copper bus wires
  • Self-regulating polymer with bonded jacket
  • Thermoplastic insulation
  • Tin coated copper earth braid
  • UV resistant thermoplastic overjacket

Maximum Length (m) / Circuit Breaker Size (type C)

Cable Start-up Temp (˚C) 6A 10A 16A 20A 32A
GP-18 +10 26 42 68 84 90
  0 24 38 62 78 86
  -15 20 34 54 68 80


If you would like the experts at BN Thermic to select a gutter protection system for you, please send an email to  with details of your application and we will respond with detailed proposal.

Cable selection for gutters

A single run of GP-18 self-regulating heating cable will protect gutters with widths up to 120mm.  For wider gutters add an additional run for every 120mm increase in width.  For example a 350mm wide gutter will require 3 runs of cable.

Cable selection for downpipes

For downpipes at the end of a gutter a single run of GP18 self-regulating cable will be required.  The cable should extend approximately 500mm below ground level.

For downpipes which interrupt a gutter, a loop of cable should be installed with the end of the loop extending approximately 500mm below ground level.


THK termination kit should be used to prepare one end of the cable for electrical connection and to seal the far end

Electrical connections should be made in a THJ IP66 junction box

Spacer Kits

A GP-S spacer kit consists of five stainless steel spacers and 10 UV resistant cable ties.  The spacers are used to protect the heating cable as it passes over a sharp edge and to maintain the correct spacing when multiple cable runs are installed in a gutter.


Control by means of FST2-EX (20A 230V) IP65 thermostat is recommended for economy.