Technical Instruction

Waterproof Connections between the Transformer and a LED Fixture

Creating a waterproof connection from 12 volt AC transformer to a LED lighting fixture.

Accepted Landscape Contractors’ Industry Standard procedure and practices for outdoor low voltage lighting installation, calls for waterproof low voltage connection from the LED fixture driver conductors to each side of the low voltage transformer mainline cable. The waterproof connection requires a waterproof splicing gel, such as Dielectric Silicone or GE Silicon II to insulate the connection of the fixture conductors to the transformer mainline cable. This waterproof splicing gel must be sun/freeze proof that remains permanently waterproof, shrink and crack proof with said splicing gel covering any exposed copper wire leads from the fixture conductor wire and mainline cable. This waterproof splicing gel must be protected by an additional durable protective enclosure at the connection point.

Failure to insulate the exposed copper wire and the immediate adjacent rubber insulation covering the exposed wire allows moisture to wick onto the copper wire. Moisture wicking onto the copper wire under the Vac/Vdc and mainline cable insulation, can create electrical shorts, will corrode the copper wire, create voltage drop and comprise the LED Vac/Vdc driver causing it to fail.  

The connection must be waterproof with a tight connection at the wire ends.  To insure a tight lasting connection a copper crimp connector sleeve is recommended. A loose connection at wire ends creates heat resistance leading to voltage drop and can melt the wire insulation of the driver.