There is more electrical equipment in a garden than you might think: path lights, gate lamps, a well or borehole pump, a fountain or pond, automatic irrigation, a doorbell, intercom, cameras and an alarm. Some of these run on 230 V mains, others on low-voltage 12 V transformers or batteries.
All of it lives with rain, snow, dew and temperature swings. Over time moisture gets into the boxes, contacts corrode and insulation ages, leading to faults: lights flicker, the pump fails to start or the RCD trips. A yearly check, ideally in spring after the winter, prevents most of these problems.
What you will need
Important: Only work with the circuit breaker for that line switched off and confirm there is no voltage with a tester. If you find melted insulation, signs of arcing or water inside a consumer unit, call an electrician.
Step 1
Isolate the circuit and walk the route
Switch off the breaker for the outdoor circuit and check with a tester that it is dead. Walk the entire route: lights, junction boxes, switches, sockets and the pump connection. A properly installed outdoor system runs in conduit or ducting, with boxes and switches in housings rated for water protection. Check that covers are intact, housings are not cracked and cables have not been nicked by a spade or mower.
Step 2
Open the boxes and check the contacts
Carefully open junction boxes and switch housings. Look for condensation droplets, cobwebs, ants, green or white deposits on terminals and darkened insulation. Tighten loose screw terminals and remake and insulate any damaged joints.
Treat connections whose condition you cannot judge by eye (wire caps, terminal blocks, plugs) with WD-40 Specialist Contact Cleaner. It penetrates quickly, displaces condensation, dissolves oxidation and dries without residue. Allow a few minutes for it to evaporate before closing the box.
Step 3
Check seals and housings
Rubber cover gaskets harden over time and then let water in. Replace cracked ones, and clean and treat sound ones with WD-40 Specialist Silicone so the rubber stays supple and seals tightly. Treat metal lamp housings, brackets and screws that are starting to rust with WD-40 Multi-Use, on the outside only and never on live parts.
Step 4
Service pumps and low-voltage systems
On 12 V systems pay attention to the transformer and to the far-end connections, especially where the device sits in water, such as a fountain pump or underwater lights. Clean the connectors with contact cleaner and make sure they are above water level or properly protected. Doorbell and intercom buttons at the gate also corrode often: remove the cover and treat the contacts.
Step 5
Check battery-powered lights
Inspect the battery compartments of LED lights, doorbells, sensors and cameras. Leaking batteries or corroded springs cause poor contact: clean them, treat them with Contact Cleaner, fit fresh batteries and make sure the compartment cover closes tightly.
Step 6
Temporary wiring and festive lights
Festive lights and extension leads used outdoors must be rated for outdoor use. Keep plug, socket and adaptor connections under cover or in protected boxes, never on the ground or in snow. Before setting up, check the cables for cracks and clean the plug pins with contact cleaner. Then switch the breaker back on and test the whole circuit.
Tip: Carry out the check in spring, when moisture in boxes is most often found after the winter, and again in autumn before the rains. A quick burst of Contact Cleaner into a pump or lamp connector every time you open a box takes seconds and makes the contacts last much longer.
What next
A yearly inspection keeps outdoor electrics working reliably for years. The same WD-40 Multi-Use is useful for garden tools, gate hinges and gate locks.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».