Festoon lights strung over a bar are the quickest way to make it feel like a celebration. They are also an outdoor electrical product, so the small print on the box matters more than the bulb shape.
What an IP rating is
An IP rating, from the Ingress Protection system, uses two digits. The first describes protection against solid objects such as dust and fingers. The second describes protection against water. Higher numbers mean more protection. An "X" in place of a digit means that aspect has not been rated.
For outdoor lighting, the water digit is the one most people care about. A product intended for exposure to rain should carry a rating suitable for that position, and the maker's instructions will say where it can be used.
The whole set has to be rated
The bulbs might be rated for outdoor use while the plug-in transformer is indoor-only. That is common with low-voltage sets: the transformer stays inside or under cover, and only the low-voltage cable runs outside. Read the instructions for every component:
- Bulbs and lampholders.
- The cable and any connectors between lengths.
- The transformer, driver or controller.
- Any timer or smart plug.
Mains or low voltage?
Low-voltage festoons run from a transformer, reducing the voltage in the outdoor cable. Mains-voltage festoons are often used for permanent or commercial-style installations and should be installed with appropriate protection. Electrical Safety First recommends RCD protection for electrical equipment used outdoors.
A permanent lighting circuit for a garden bar belongs in the wider power plan, installed by a competent electrician.
Hanging them safely
- Use a support wire for long spans so the cable is not taking the weight.
- Keep connections off the ground and out of puddles.
- Avoid hanging lights where they can catch on umbrellas, heads or tall guests.
- Keep strings away from heaters and fire pits.
Bulb colour and brightness
Warm-white bulbs give the classic pub-garden glow. Very bright or cool-white bulbs feel harsh and carry further into neighbouring gardens. Dimmable sets let you start bright for setting up and drop the level for the evening. See the lighting guide for layering.
Winter
Many people leave festoons up all year. Check the instructions on whether that is intended, and inspect cables, connectors and fixings each spring. Replace anything cracked or water-stained.
Count the bulbs before you buy
The festoon light planner adds up your spans and droop, then counts bulbs and sets from the product's own spacing and linking limit.
Before buying, check the IP rating of the transformer as well as the bulbs. If the box does not tell you, the product page should, and if neither does, choose another set.
Sources
Primary guidance checked 10 November 2026.