How To Fix & Change Christmas Light Bulbs

Changing the bulb on a set of Christmas lights whether indoor or outdoor is usually much easier than you may think. In this guide, we explain how to change a bulb and general Christmas lighting safety tips.

If you're currently using the older style, filament bulbs on your Christmas lights (you know the ones - where the little bulbs can be pulled out to be replaced), then you'll know just how easy is it to accidentally step on and shatter a bulb or two, especially when you've just got them down from the loft and are trying to untangle the heap of knotted wires.

Then once untangled and decoration on your tree or home, you go to plug them in to find that they aren't lighting up! Usually it's just one bad bulb that is causing the black out, but on other occasions a fuse may have blown, or there can be a corroded or bad connection, or maybe a broken wire. In this guide, we explore the most common faults for why Christmas lights don't turn on, and how to easily replace a bulb if and when needed.

It should be noted though, prevention is always better than cure, so make sure that the bulbs are looked after correctly, and when packing away to store for next Christmas, future you will thank you for winding the wires up carefully, and packing the lights away in a secure box so that they don't get damaged or broken.

A person sitting on a sofa holding a big bunch of tangles Christmas lights.

Top 3 fixes for getting your Christmas lights working again

Firstly, whether brand new out the box or reused from the previous year, always take care when unpacking your Christmas lights in order not to cause any damage, especially when pulling on any wires, or dragging the light bulbs along the floor. And before you start, make sure that your Christmas lights are not plugged when doing any electrical checks and/or changing any of the bulbs.

No.1 Check the wiring for any damage
Give your set of lights a good look over. Make sure to pay extra attention to the plug's wiring, ensuring that it is correctly still in place, and that there are no frayed or loose wires. Also check the wiring going into each bulb and the control box (if there is one), and along the string in general to ensure that are no cuts in the wire, otherwise a new set of lights is called for rather than trying to attempt a DIY fix.

No.2 Check the fuse in the plug
When an entire string of lights go out, you should initially check the fuse in the plug, as this is one of the easiest and quickest things to replace if found out to be the route cause. Remove the plug from its socket, open/unscrew the fuse cover, take the fuse out and replace it with a new one of the same rating. If the lights come back on, throw the old fuse away and carry on with your Christmas. If not, it is most likely that one of the bulbs has failed.

No.3 Check each individual bulb
Probably the fix that you least wanted to hear due to the time it takes to complete, but Christmas lights with the small filament bulbs can be gently removed and pulled out.

To start off this fix, you will need a brand new spare bulb to work with. Then, work your way through each bulb within your set one by one, gently pulling out the bulb, and popping in the spare one in its place. When taking out the current bulb, you should see two metal connectors/leads at the base of it, check whether these are both present and not misplaced in any way. Also check the contact inside the small socket where the bulb sits, this might be damaged or corroded. As long as the inside of the bulb socket looks good, pop the spare bulb in, turn the light set on and see if the rest of the lights turn back on. If they do, this means that you've found the culprit bulb, and successfully replaced it with the spare!

If you can't see a fault in the bulb holder, with the bulb that was taken out, and the lights still don't come come on with the replacement bulb in, put the original back and then continue this process along the string with the remaining bulbs.

As these older-style bulbs have a much shorter lifespan than their LED equivalents, they can give up at anytime, or accidentally get trodden on or smashed, and so checking them one by one is the only sure fire way to finding a dud bulb!

A set of colourful Christmas lights turned on and glowing.

Replacing your Christmas lights set

If you're unable to get your original set of lights working, it may be time to buy a new, up to date set instead, especially if you're old set is still using the old style filament bulbs. The majority of modern-day Christmas lights now use LED's, as they are safer to run by emitting less heat, are much stronger and longer lasting (many brands claim they can be trodden on without damaging them!), and will also save you money as they consume less electricity.

Another advantage of LED's is that if one bulb fails it does not affect the rest, they will still stay lit. Although, one disadvantage is that LED bulbs cannot be replaced.

If you need to replace your current set, shop our range of indoor and outdoor LED Christmas lights here.

Six safety points for your Christmas lights

  • When you notice that a bulb has ‘blown’, switch off the power. It's important never to remove or insert bulbs when switched the power is on.
  • Replacement bulbs should have a British Standard Kitemark and bought from a reputable retailer. Buying second hand is never recommended. Always buy like for like, don’t mix bulbs from different sets. The code number for spare bulbs should be listed on the item’s original box.
  • For extra safety, especially when changing a bulb outdoors, consider buying a residual current device for an outdoor display. With an RCD if the power for some reason is still on and you touch a live wire, the circuit disconnects and prevents you receiving an electric shock.
  • Store lights out of the reach of children, Christmas tree lights are very attractive and equally easy to swallow. When you are concentrating on replacing lights, don't leave the old lights or replacements lying around.
  • If you have to use a ladder to reach the bulbs in an outdoor display, make sure it is sturdy and fit for purpose. Ask someone to stand on the bottom rung or hold the ladder steady.
  • When the bulbs are up and running again don’t forget to switch indoor lights off when you go to bed or leave the room.