An outdoor lighting transformer is the electrical device that converts the electricity coming from your household outlets – which is roughly 120 volts – to the 12 volts used by virtually all modern LED landscape lighting fixtures, as well as the less-efficient (and mostly antiquated) 12 volt halogen bulbs that were common before LED lights became reliable and affordable.

At your home, your landscape lighting transformer is most likely located somewhere outside, although occasionally you can find your transformer in the garage.

Why use a transformer at all? For starters, 120 volts is dangerous while 12 volts is considerably safer. OSHA has guidance on this. Quick summary: OSHA considers all voltages of 50 volts or higher to be hazardous.

While you could certainly install an outdoor lighting system that operates on 120 volts, you’d need a dedicated circuit on your electrical panel, you’d need to run ALL of your wiring inside buried conduit and make ALL wire connections inside junction boxes. That system would be expensive to install AND expensive to operate. But none of that is necessary with an energy-efficient low-voltage system.

With a 12 volt system, insulated wire can safely be buried directly in the ground. Why?  First of all, electrical codes allow it! Electrical codes allow it because the output from a 12 volt transformer is highly unlikely to shock anyone or create sparks and fires. (A note of caution: Any current passing through your body can be harmful. You can get painful little “burn” on your skin if negative and positive 12 volt wires touch bare skin very close together!)

A high-voltage system is not only expensive to install, it’s also expensive to operate. An outdoor lighting system utilizing a transformer and 12 volt fixtures is extremely economical to operate. We don’t like to say “pennies a night” because it’s more like a few dimes, but it’s not expensive!