WHAT TO DO IF I HAVE MOISTURE BUILD UP IN MY LIGHT FIXTURE?
Moisture build up in outdoor lighting can be a common occurrence in many different types of outdoor fittings. But should this be a cause for concern? And is there anything you can do to prevent it? Read on to find out more...
Important: When checking a light fitting always ensure that the power is isolated or turned off at the mains to eliminate any danger.
How much water is in the fixture?
Some condensation vs. Filling up with water.
If you have a 230-240V fixture filling up with water, this is very likely dangerous. Power supply to the fixture should be isolated immediately and not switched back on until a registered electrician has checked it.
Condensation in some situations is inevitable and is not a reason to worry. Most light fixtures have ventilated light sources to provide long lamp life. This is a particularly important design feature for high wattage fixtures. Nevertheless, electronic control gear if integral with the fixture will be placed in an IP65 enclosure.
Depending on the installation position condensation can be apparent especially inside clear lenses. This condensation normally occurs when the fixture is cooling.
New light fixtures commonly use integral LED technology or an LED bulb. With LED’s not running so hot the moisture is not evaporated as easily as with pervious lighting technologies such as halogen or incandescent which ran much hotter, the prevalence of some condensation build-up may have increased slightly since the change in technologies.
Many exterior lighting products are designed with “moisture valves” or “anti-siphon” valves being incorporated into the fixture or on the power supply cable. In any case it might be impossible to expect no condensation at all, however there is a lot that can be done when installing and maintaining outdoor light fixtures to prevent excessive moisture accumulation.
Avoiding Water Absorption & Condensation.
What is the best way to install an outdoor light fitting to avoid these common problems?
Exterior Wall Lights
The power supply cable which runs from the house wall into the fixture can make the perfect route for water to enter the fixture. As water runs in-between the house and lighting fixture and down the power supply. This can be prevented by making sure the cable runs up towards the entry hole rather than down into it.
In New Zealand we use TPS wiring which is wide and flat and fixtures usually have a round hole with rubber gromet for the power supply to enter through. It is important to make sure there is a silicone sealant applied at installation around this entry hole to ensure all gaps are eliminated.
Bollard Lights
Bollards should not be placed in an area where water can pool around the bottom of them. Likewise wiring connections should be well above ground level with High IP protection (ingress protection) or be made to a high IP level using special IP connectors or boxes.
Good preparation of the mounting location should be completed before installation of the bollard.
The ideal mounting location needs to be level and set in an area not prone to flooding. It is highly recommended that a purpose made raised concrete pad is made for the bollard to be installed on, this will ensure a trouble free and future proofed installation. The surrounding area should have adequate drainage in place.
Example of Purpose made concrete base – dimensions and design would vary dependent on size and style of mounting base of bollard.
Pole Lights – Inground Mounting
Inground poles require a length of pole to be installed below ground level to ensure its rigidity.
A hole depth 0.5 to 0.6 metres for a 2 to 3-metre-high pole is a good guide. Place 100mm of gravel in the bottom of hole and ensure the bottom is imbedded into it for drainage. Prop up the pole to stand up vertically. Pour Concrete around base to just below the cable entry hole, this allows about 100mm of earth over the concrete and will keep cable accessible yet concealed (see diagram).
The power cable is usually installed inside protective conduit all the way through from the ground and up into the pole. Wiring connectors should be well above ground level and ideally at top of the pole. if connections are at or below ground level connections must be made to a high IP level using special IP connectors or boxes to ensure water tightness.
Recessed and Inground Lights
It is important to choose your mounting position carefully, make sure there is adequate drainage around the inground light. The fitting must never be sitting in water.
Mount into a raised or level area and not in a dip. If the pavement is not on a gravel bed, install a drainage pipe along with the electrical conduit. Ensure IP connectors or connector boxes are used where cables are connected outside. IP connectors must seal to the outer sheath of the cable to prevent siphoning moisture up the cable.
Garden Spike Lights
When run off SELV (Safe Extra Low Voltage) power supply, the risk of electrocution from 12Volt garden lights is not an issue as the fixtures would be perfectly safe sitting in a bucket of water. However, water ingress will cause failure of electronic components. Therefore you must keep extra low voltage connections watertight and sealed over the outer sheath of the cable so that the fixture cables do not siphon water up and into the lighting fixture.
Likewise, fixtures should be placed in areas away from dips where puddles will form with long periods of rain.
Maintenance For Your Outdoor Light Fixtures
It is important from time to time to check your exterior light fixtures. When replacing bulbs, ensure that the light fixture is reassembled well afterwards, seals are aligned and screws tightened evenly and strongly. It is important to know that very few outdoor light fittings are made to be water blasted and pressure hosed. Any fixtures with an ingress protection below IP65 are not designed to be water blasted - and some fixtures are only protected from a specific angle.
Overtime leaves, dust and debris may gather or accumulate in crevices or gaps in your outdoor fixtures. Clearing these away will help keep the ventilation and drainage galleries in the light fixture functioning correctly.
Other Useful Links:
Outdoor Light Material and Finishes Guide
Dust and Water Ingress Protection Ratings