How permanent roofline lights get their power
What plugs in where: the low-voltage power supply, the spots it can live on a Michigan house, why big rooflines get more than one feed, and the power questions to take to your electrician.
Low voltage in plain English
Most permanent roofline lights do not run on the same power as a lamp in your living room. LED strips like these typically run on low-voltage direct current, so a power supply sits between your house wiring and the lights. Household current goes in one side, low-voltage DC comes out the other, and a wire carries it up to the start of each run on the fascia.
A separate controller, often in the same enclosure or right beside it, decides what the diodes do: which color, how bright, which zone and at what time. The power supply provides the energy. The controller provides the instructions.
A guide from the LED retailer Super Bright LEDs explains that UL Listed LED strip lights are listed for use with Class 2 power supplies, and that UL 1310, the safety standard for those supplies, caps their output at 60 volts DC, 5 amps and 100 VA. Power supply maker Advanced Energy adds that a Class 2 unit cannot deliver more than 100 VA of continuous power under any load. The ceilings exist to cut the risk of fire and shock on the low-voltage side.
What this means for you: on a low-voltage system, the wire along your eaves carries low-voltage DC, not household current. It still deserves a careful install, but it is a very different thing from an extension cord stapled to the trim.
Where a power supply can go
The power supply has to live somewhere between a source of household current and the first light, and the best spot depends on the house. There is no one right answer, and the placement for your home gets settled on site, before anything is ordered. These are the usual options and what each one trades.
| Location | Why it works | What to watch |
|---|---|---|
| Inside an attached garage | Dry, out of the wind, near an outlet, and often a short hop to the front fascia | Needs a tidy path through the wall or soffit, and an unheated garage still gets bitterly cold in January |
| Outside on a wall, in an enclosure | Close to the roofline, with no hole into living space | The enclosure must be rated for outdoor use and mounted above where snow drifts or plow piles land |
| In the attic or above a soffit | Out of sight, with the shortest wire to the eaves | Harder to reach for service, summer attic heat, and it may need a new outlet up there |
| Basement or utility room | Warm, dry and easy to reach | The longest path up to the roofline, which matters for voltage drop |
On many colonials and ranches around Macomb and Oakland County the attached garage sits right at the front roofline, so it comes up often. A split-level with the garage tucked under the upper floor, or a side-entry garage, changes the picture. So does a brick or stone front, where a new hole is a bigger decision than on vinyl siding.
Weatherproofing is the other half of placement. Any enclosure should be rated for where it sits, the wire should enter the house through a weather-tight penetration, and a wire coming down a wall should dip in a small loop below its entry point, so meltwater drips off the loop instead of following the wire inside.
Why long runs are split
Low-voltage power has one weakness: it fades over distance. The Super Bright LEDs guide names two things that limit how far a strip of LEDs can run from a single feed. One is voltage drop, which shows up as lights getting noticeably dimmer the farther they are from the power source. The other is the 100-watt and 5-amp ceiling of a Class 2 supply. Push past either and the far end of the roofline looks tired, or the run asks for more than one Class 2 supply is allowed to deliver.
So a long roofline is not one continuous wire from one box. It is broken into runs, and each run gets power at a point where it can hold full brightness end to end. Sometimes that means feeding a run from the middle rather than from one end. Sometimes it means more than one power supply. The layout comes from the measured footage when the system is designed, not from guesswork on a ladder.
Footage is what drives the plan, and it varies a lot across the area:
- A Macomb Township ranch carries about 60 to 80 feet of front roofline, one story and a simple shape.
- A Troy colonial runs 120 to 180 feet of front roofline, climbing over gables and a garage. More footage means more runs to plan.
- A large two-story with wings in Bloomfield Township reaches 250 to 400 feet once the wings and the garage are counted. At that length the power layout is its own piece of the design, section by section.
Splitting pays off later too. With a zoned layout, a dead section points to itself from the controller, and nobody takes the whole roofline apart to hunt for it. Power runs and phone-controlled zones are separate ideas, but both are planned from the same roofline measurements.
The outdoor outlet: a question for your electrician
The power supply needs household current, which usually means an outlet or a circuit near where the supply will sit. Whether yours is suitable is a question for your electrician, and a quick one to ask well before install day.
Some background helps. The NFPA, which publishes the NEC, the national model code for electrical wiring, notes that section 210.8(A) of the 2020 edition calls for GFCI protection on receptacles outdoors at homes, along with garages, basements, kitchens and other damp areas. A GFCI outlet is the one with test and reset buttons. The same NFPA article points out that one GFCI can protect ordinary outlets elsewhere on its circuit, so a porch GFCI might protect a plain-looking outlet on the back of the house, and the protection can also come from a GFCI breaker in your panel.
That matters for permanent lights. If the roofline goes dark one evening while everything else works, the cause may be a tripped GFCI somewhere you would not think to look. Knowing which device protects the lighting circuit saves a service call. Which code edition your township enforces, and what it means for your house, is for your electrician or your township building department to say.
Questions worth handing your electrician:
- Is the outlet nearest the planned power supply GFCI protected, and where is the device that protects it?
- What else shares that circuit? A garage freezer or a roof de-icing cable on the same line is worth knowing about.
- Does the outdoor cover stay closed with a plug in it, or does it only shut when nothing is plugged in?
- If the best spot for the supply has no outlet at all, what would adding one involve?
How much the lights draw each month is a separate question, answered in what permanent lights add to a power bill.
Controller and Wi-Fi placement
The controller is the part your phone talks to, and it needs a decent connection to do that. If it ends up at the far end of an attached garage behind a brick wall, your home Wi-Fi may reach it weakly or not at all. Masonry, foil-faced insulation, a metal garage door and a steel shelf full of paint cans all get in the way of a signal.
A two-minute test tells you a lot. Stand where the controller is likely to go, check the Wi-Fi bars on your phone, then try loading a video. If it stalls, a mesh node or extender on the house side of that wall is usually simpler than moving the power supply. Have your network name and password handy on install day.
Ask whether the controller keeps its colors and schedules after a power flicker or a Wi-Fi outage. Scheduling, zones and the app are covered in our guide to smart roofline lights and schedules.
What to check before install day
A short walk around the house before the visit speeds up the power conversation and turns up surprises while there is time to fix them.
- Find your outlets. Note every outdoor and garage outlet near the front roofline, and which ones have test and reset buttons.
- Test the GFCIs. The NFPA recommends following the manufacturer's instructions and testing GFCI outlets and breakers monthly at a minimum. Press test, confirm the outlet goes dead, then press reset.
- Bring in your electrician early. If an outlet is missing, loose or will not reset, get it looked at before install day, not after.
- Clear the wall. Move shelving and stored items away from the garage wall closest to the front roofline so it can be reached.
- Check Wi-Fi at the spot. Run the signal test above where the controller is likely to sit.
- Remember last winter. Note where snow drifts or plow piles land against the house, and keep anything electrical clear of that line.
Building a new house? You can plan an outlet and a path for the wire before the drywall goes up, which is far easier than working around finished walls. Our guide to planning permanent lights on a new build covers that timing.
Start with your footage
Every power question above comes back to one number: how many feet of roofline you want lit. Take a straight-on photo from the street and let the LightCast tool trace your roofline. Mark your garage door as the known width, and you get the feet, the peaks and valleys, and a permanent and seasonal price side by side. The image is processed inside your browser tab and is never uploaded.
Happy with that range? Ask for an estimate and we confirm within 24 hours. Final footage and the spots for the supply and controller get settled at the house before anything is ordered, so bring your electrician's answers along. For the rest of your list, see our questions to ask a permanent light installer.
Questions about this
Do permanent roofline lights need an electrician?
It depends on your house. The lights run on low voltage from a power supply, and that supply needs household current. Whether your existing outlet and circuit can feed it, or whether something should be added or changed, is a call for your electrician to make before install day.
Why did my permanent lights go dark when nothing else did?
Check for a tripped GFCI first, including one on another outlet or a GFCI breaker in your panel.
Can the power supply sit outside?
It can, as long as its enclosure is rated for outdoor use and it is mounted where water, drifting snow and plow piles cannot bury it. A dry garage close to the roofline is the common alternative.
Where this applies
Typical roofline lengths and priced examples for these communities are on their own pages.