A good rule of thumb for selecting proper wire size is determining your wattage.
Landscape lighting wire diagram.
Most low voltage landscape lighting wire comes in two different sizes.
Any system under 200 watts will be fine using 16 gauge wire.
Wiring schematic diagram low voltage lighting landscape light fixture lights led 840 landscaping yr 8460 driveway spotlight wire outdoor install system layout.
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Second you need to be able to distribute equal voltage to every single fixture in your landscape lighting system and that takes a well planned wiring method.
Place one wire from each main run with one wire from the fixture.
12 and 16 gauge.
How to splice a light into a run of outdoor lighting cable.
The only wiring method that can get equal voltage to every fixture is an equalized hub method of wiring.
Over 200 watts you should use a 12 gauge sized wire.
Strip the end of each wire so that 3 4 of bare copper is exposed.
Repeat with other wires.
Http lightingdoctor ca learn how to wire low voltage landscape lighting with an easy to follow wiring diagram demonstration.