Nobody wants to be thinking about Christmas lights in September. The owners who end up with the cleanest install (no nuisance GFCI trips, controllers that actually do what they are supposed to, and lights that come on at dusk without an extension cord running through a window) plan the circuit in September. By the second week of November the LED clearance pricing is gone, the smart controllers are sold out, and every electrician in town is booked solid for outdoor receptacle work. Here is what we are walking homeowners through right now across Hamilton, Burlington, Ancaster, Oakville, and Waterdown.
What the circuit math looks like
Modern LED Christmas lights draw much less than the old incandescents. A 100-bulb string of warm white LEDs typically pulls 4-7 watts. A homeowner can run 20-40 strings in series on a single 15A circuit without coming close to limit. That is the part everyone knows.
The part people forget: the GFCI will nuisance-trip well before the breaker does, and it does not care about watts — it cares about leakage current. Every set of lights has a tiny amount of capacitive leakage to the grounded surrounding (siding, eaves, downspouts, ice). Add 30 strings together and the cumulative leakage adds up to enough to trip a 5mA GFCI even though you are nowhere near the breaker's amperage limit.
What this means in practice: a typical decorated house in 2027 wants 2-4 dedicated GFCI-protected exterior circuits, not one. Splitting the lighting load across multiple GFCIs keeps the per-circuit leakage current well below the trip threshold, and the lights stay on through the freezing rain that used to take them out.
What we install in September for December
For homeowners who want a clean Christmas light setup with no extension cords through windows and no trips on the first wet night, the install we do most often:
- Two to four dedicated 20A exterior circuits distributed around the house — front, back, garage soffit, and any specific high-light areas (large feature trees, dock for waterfront properties).
- One receptacle per zone, mounted at the soffit or eave where the holiday-light contractor will tap in. WR-rated, in-use cover, GFCI breaker upstream at the panel (not at the receptacle).
- A switched circuit at the panel or a smart timer controller (Lutron Caseta, Leviton Decora Smart) so the whole holiday display turns on at dusk and off at midnight without anyone touching a plug.
- One dedicated permanent-display circuit for owners going the route of installing year-round permanent holiday lights (Trimlight, Gemstone, Everlights, Oelo) along soffits. These permanent systems are a separate conversation and need their own dedicated circuit and controller location.
The "permanent holiday light" question
Permanent eaves-mounted RGB LED systems have grown a lot in the last few years. The product is good — properly sealed, programmable for different holidays and events, app-controllable, and the install is one-time. The electrical scope:
- Dedicated 15-20A circuit at the location of the controller, typically inside the garage or attic.
- Low-voltage runs from the controller to each soffit section.
- Controller location chosen for thermal management (an attic in July is the wrong place).
- Surge protection at the controller — the controllers are pricey and lightning-sensitive.
If you are weighing a permanent-light install versus continuing to hang traditional lights every year, the electrical pre-work is the same week in either case. Worth doing now so the install crew has the circuit waiting in November.
The smart controller landscape
For straight on-at-dusk-off-at-midnight scheduling, we install in order of preference:
- Lutron Caseta with the Pico remote and the astronomical timer schedule. Most reliable in our experience, no internet dependency for basic scheduling, and the dimmer compatibility is unmatched if you have any dimmable LED feature lights.
- Leviton Decora Smart with Matter. Comparable to Caseta, ecosystem-flexible, slightly better if the homeowner is committed to Apple Home or Google Home as the central hub.
- Lutron RA3 panel-level controller for homes that already have an RA3 system or want one. Schedule the holiday circuits along with everything else in the house.
For most homes a single $80 Caseta switch at the panel-end of a dedicated exterior circuit does the job. The fancier setups are nice but not necessary.
The fall LED clearance window
September through mid-October is when the previous-season LED inventory at Home Depot, Costco, and the specialty Christmas-light retailers is on real clearance. Quality LED light strings from C9, Wintergreen, and Christmas Light Source (the brands the professional installers use) are routinely 40-60% off through this window. Owners who buy lights in late November pay full price for whatever is left after the picked-over month.
If you are upgrading from incandescent to LED this year, do the math: a typical large house using 1500-2000 incandescent bulbs draws 4-6 kW. The same coverage in LED draws 200-400 watts. The clearance LED purchase pays itself back in a single season on electricity alone, plus the GFCI nuisance trips disappear because the leakage current is also dramatically lower.
The extension cord trap
The dominant failure mode for Christmas light installs is still the homeowner running a heavy extension cord from an interior receptacle, under a sliding door, and out to the lights. The risks:
- Pinched cord under the door eventually wears through the jacket. Conductor exposed in winter, in a wet location, is a fire and shock risk.
- The interior receptacle was never intended for outdoor continuous use and the GFCI (if any) is upstream of a long indoor run.
- Sliding doors with cords running through them do not seal, and the heat loss is meaningful over a winter.
The fix is the same fix as last year and the year before: install proper exterior receptacles in the locations where the lights actually go up. Once, not every year.
What the controller does in February
After the holiday season ends, the dedicated exterior circuits and the smart controller do not become dead weight. They are useful for:
- Landscape lighting and pathway lighting that comes on at dusk.
- String lights on a deck or patio for summer.
- Festival lighting for parties.
- Future permanent holiday-light installs.
The circuit is paid for once. It works year-round.
When to call us
If you want exterior lighting circuits and controllers installed before the holiday rush, we cover Hamilton, Burlington, Waterdown, Ancaster, Dundas, Stoney Creek, and Oakville, and we are not yet booked solid for November the way we will be in three weeks. Request a quote with a sketch of where the lights go and we will scope a clean install (exterior receptacles, dedicated circuits, smart timer at the panel) that you will use for the next 15 years of holiday seasons.