Christmas tree lights and fire safety: a practical checklist

This guide is general information, not electrical or fire-safety advice. Always follow the instructions and labels that come with your tree, stand and lights.

Real or artificial: what actually changes

Both are fine when they are chosen and cared for properly. The difference is where your attention goes.

NFPA advises that an artificial tree be labeled, certified or identified by the manufacturer as fire retardant. That is not the same as fireproof, but it indicates the material was made with fire performance in mind.

Choosing a fresh real tree

A fresh tree has green, pliable needles that do not shed in handfuls. Two simple tests are widely used:

• The bend test. Take a needle between your fingers and bend it. A fresh needle bends and does not snap.
• The tap test. Lift the tree a few inches and tap the trunk on the ground. A few brown inner needles may fall, but a shower of green needles means the tree is drying out.

Also look at the trunk: sap should be sticky, and the base should not have a dry, grayed look. Cutting about an inch or two off the bottom of the trunk before you put it in water, as NFPA recommends, gives the tree a fresh surface that can take up water. A tree should go into water as soon as possible after that fresh cut, and the stand should never run dry.

Place the tree safely

• Heat sources. Keep at least 3 feet between the tree and fireplaces, radiators, space heaters, heating vents, candles and any other source of heat.
• Traffic and exits. Do not block doors or exits, and place the tree on a firm, level surface where it will not be knocked.
• Stand. Use a stand that fits the trunk and holds enough water. A guideline often given by tree-industry groups is about one quart of water for each inch of trunk diameter.
• Smoke alarms. Test them before the tree goes up.

Choosing the right lights

Indoor or outdoor, and who tested them

Check that your lights are marked for the use you intend, indoors or outdoors. Look for a listing mark from a recognized testing laboratory on the tag or plug, which shows the product was tested to a safety standard. NFPA also advises inspecting every set before use.

LED or incandescent?

LED strings use much less power than traditional incandescent mini lights and generally stay cooler to the touch, which is a real plus on a real tree. Incandescent strings give the warm color many people prefer, though modern LEDs offer warm-white options that come close. Whichever you pick, you should not mix different sets on the same run unless the manufacturer says it is fine.

Inspect before you plug in

Lay each set out on the floor, plug it in and check:

1. Cracked, frayed or bare wire, or damaged insulation.
2. Loose or broken bulbs and sockets.
3. A hot plug or cord, or the smell of something hot.
4. A flickering section that does not respond to replacing a bulb.

Throw away any strings with damage rather than taping them up. Replace bulbs only with the type specified for that string.

How many lights, and how many strings can connect?

A familiar rule of thumb is about 100 mini lights for each vertical foot of tree for a classic look, with 50 per foot for a lighter style and 150 per foot for a dense one. That puts a 7.5-foot tree near 750 lights. Our tree decoration calculator does the arithmetic for your own measurements.

More important than the count is the connection limit. Each set has a maximum number of strings that can be connected end to end, which is printed on the tag or box. Exceeding it can overheat the wire and blow fuses. LED strings usually allow more sets in a run than older incandescent ones, but the label rules.

Use outlets and cords wisely

• Do not overload outlets or power strips. Plug heavy loads into different circuits.
• Use cords sized for the load and rated for where you use them.
• Route cords so they cannot be pinched in furniture, run under rugs or create a tripping hazard.
• Use a timer so the lights go off at night. NFPA recommends switching lights off when you leave the house or go to bed.

Pre-lit trees and sets that stop working

If a section of a pre-lit tree goes out, check that the plugs are fully seated first, then look for a loose or burned-out bulb at the start of the dead section, as the manufacturer's instructions describe. If it remains dark, stop; do not splice wires or jumper sockets. Many modern strings include a replaceable fuse in the plug, so check the instruction sheet.

Candles, fireplaces and other flames

Do not use lit candles on or near a tree. Keep matches and lighters out of children's reach, and never burn wrapping paper or tree branches in the fireplace.

A short safety checklist

• Smoke alarms tested.
• Tree at least 3 feet from heat sources.
• Fresh cut and daily watering for a real tree.
• Every light set inspected and labeled for its use.
• Connection limits respected.
• Lights turned off when you leave or sleep.
• Tree removed when it is dry.

Taking the tree down

Remove a real tree when it starts shedding heavily or the needles become dry and brittle, which can be sooner than you expect in a heated house. Many communities run tree-recycling programs, and the details vary, so check your city or county website. For artificial trees and lights, let everything dry, coil cords loosely and store in a cool, dry place.