FX Transformer Load Budget: Do the Watt Math Before You Open the Box

Sum the fixture wattages, add about 20% for growth, then pick the next FX transformer size up — not the one that lands exactly on the number. Owners always want one more uplight after they see the first night.

Voltage drop matters more than nameplate watts on long property lines. Heavier gauge cable or a second home-run often beats a larger transformer alone. Multi-tap secondaries help when one leg is short and another stretches to the back fence.

Mount the unit on a solid wall, keep the GFCI outlet accessible, and photograph the tap chart before you close the cover. That photo saves the next tech an hour.