Installing Weatherproof LED Drivers
There are a couple of important things to watch for when installing weatherproof LED drivers with an IP67 rating.
The first one may seem fairly obvious, but it is surprising how many installations we come across where this has been missed. Make sure you use weatherproof cable joiners and connectors.
Use Weatherproof Cable Joiners
When joining cables during the installation, it is important to ensure that you use IP67 rated cable connectors, such as the MEAN WELL CJ04 series of weather proof cable joiners. Otherwise, water could enter through the electrical connections and potentially cause a failure.
The second thing is nowhere near so obvious and is something that could easily be overlooked and that is the risk of corrosion.
Avoid the Risk of Corrosion.
In some circumstances, it is possible that metal bodied LED power supplies can corrode due to electrolysis.
This can occur if the LED driver is mounted outdoors where it is exposed to weather and is in contact with the ground, either directly, or indirectly. For example, if it is mounted on a brick or concrete wall that is exposed to rain.
This effect has been observed in MEAN WELL power supplies with metal cases, such as the MEAN WELL ELG series LED drivers.
The electrolysis process is caused by a small current flowing into the metal case from external sources.
Possible external sources include:
- The external source can be the DC output of the LED driver itself via the wiring to the LEDs it is powering.
- Other power supplies in the same vicinity.
- Other completely unrelated power sources, such as stray ground currents flowing from other electrical equipment in the house, or from dissimilar metals used to mount the power supplies. Railway and tram lines are prone to electrolytic corrosion by stray currents.
Preventing Electrolytic Corrosion
MEAN WELL Australia recommends that you consider adopting one of the following methods to prevent the risk of electrolytic corrosion:
- Protect the supply from rain. Even if the LED driver is insulated from the ground or the wall, if it gets wet, the water can provide a circuit for the stray current to find a path to the case of the LED driver.
- Insulate the LED driver from the mounting surface by using plastic mountings and mount the LED driver away from the wall so the case is not touching the wall.
- Use a sacrificial anode such as zinc to prevent corrosion of the case metal. The zinc anode must be in electrical contact with the case of the LED driver. Because zinc is more active than other metals, it will corrode first. You must keep an eye on the zinc anode and replace it if it corrodes away. Boating people use this technique to protect their steel or aluminium hulls from electrolytic corrosion. Sacrificial anodes are also used in electric hot water systems to protect the heating element.
- Use a sacrificial zinc anode buried in the ground close to the LED driver to conduct any stray current to earth. Ground the anode to the same earth point as the LED driver. The same conditions apply as above – keep an eye on the zinc and replace it if it corrodes too much.
If you have any questions concerning the installation of MEAN WELL LED drivers, please do not hesitate to contact MEAN WELL Australia.