Signal SDS Series - Two-Wire Cable Installation

SDS Series
17
Installation
TWO-WIRE CABLE REQUIREMENTS:
• Signal twisted pair cable with tinned copper conductors certified for direct burial
is recommended for optimum performance.
• Signal recommends all two-wire cable joints should be soldered in a professional
manner for maximum reliability. If not soldered, they must be tightly twisted to-
gether for a minimum distance of 30mm then clinched over. It is the installers
responsibility to provide low resistance water tight cable joints.
• Waterproof connectors must be certified for below ground use. Direct bury con-
nectors are not suitable for permanent submersion in water unless specifically
rated. Long periods of full emersion will cause connector failure.
• Great care should be taken to ensure the cable insulation is not compromised, i.e.
nicks in the inner cable insulation etc. It is the installers responsibility to en-
sure there is no electrical leakage to earth in the cable network.
• Ensure the two-wire cable is well distanced from high voltage cables. If the cable
crosses a high voltage line it must be at right angles with a minimum clearance of
600mm.
• Never install the two-wire cable in the same conduit or strapped to any electrical
high voltage cable.
LIGHTNING PROTECTION:
• For lightning protection to be effective the energy of the strike needs to be in-
stantly gated to earth.
• Connect the ORANGE wires from the SD-SP surge arrester to the O/P terminals at
the controller.
• For best results flat braided cable is used to connect to an earth stake of at least 2
metre length with a resistance to earth of 10 Ohms or less. Locate the SD-SP as
close as possible to the earthing stake.
• For additional protection, install SD-SA filter/arrestors every 300 meters or every
16 valves. Connect to an earth stake with a resistance of 10 Ohms or less to
earth.
Note: A 10 Ohm or less resistance to earth can be difficult to achieve in sandy soils. To re-
duce the damaging effects of lightning follow these three rules:
1. Ensure that no bare cable conductors are in contact with the soil.
2. Use only approved direct bury cable connectors and be careful not to nick the in-
ner cable insulation and thus exposing bare copper conductors.
3. Do not direct bury. Make sure that the DataNodes™ and DataValves™ are installed
in well drained valve boxes and are not subject to flooding or prolonged emersion
in water.
Note: Australian Standards for Lightning protection to be effective is 10 Ohms or less re-
sistance to earth.