Heating Cables are ideal for growers using media beds filled with sand or fine gravel for seedling propagation.
The Heating Cable comes with a water resistant thermostat and the cable is then submersed into the bed of fine gravel or coarse river sand.
The grower plants their cuttings directly into this media or they place trays of seedlings on top of the media bed.
The cable heats up to the required temperature and this heat is radiated into the surrounding media and anything that may be growing in the media or on top of it.
The cables are manufactured to very high standards and have a layer of aluminium armour under the PVC insulation which protects the cable and allows for easier installation.
The cable is laid out in a wave formation along the width of the table with a 50 – 70mm gap between each wavelength (to protect the cable from damage).
One 230 Volt thermostat can control more than 1 cable at one time.
The cables are unable to be trimmed shorter if there is a surplus length.
A Residual Current Device should be installed on the mains power supply for the safest operation of the cables.
Heating Cable Sizes & Prices are as follows:
All pricing includes 1 x Thermostat
Custom sizes and longer cables are also available on request.
Replacement heating cable thermostats are also available for $110.00 + GST.
Sizing and Layout
To size the cable and how it needs to be arranged do as follows:
Work out the length and width of the propagating bed area.
E.g 1.4m x 800mm = 1.12m2
Therefore a 20 metre long (200 Watt) cable is best.
Then divide the 20 metre cable by 1.4m (length of bed) = 14.28. This means you require 15 runs (wavelengths) of cable.
Then divide the width of the bed by 15 runs = 800mm/15 runs = 53mm / 2 = 26.5mm
Therefore you have 26.5mm gap on the left-hand side of the bed and 14 x 53mm gaps between the runs of cable, and a 26.5mm gap on the right-hand side of the bed.
The red part of the cable must be fully covered by sand (if it is exposed or touches another part of the cable it will melt). The insulated black part of the cable that connects to the thermostat can be exposed.
45mm gaps between the wavelength runs of the cable is the very minimum you can go to.
55 -70mm is ideal.
There must be a minimum of 25mm of sand on the floor plate of the table onto which the cable is laid.
Then there must be a minimum of 50mm of sand on top of the cable. the cable must not be exposed at any time.
One thermostat can only handle 2 x cables at any one time.
Please talk to Pure Hydroponics for pricing and further information.