Gerard Lighting Group Technical Manager and member of the Lighting Council NZ, Mike Austin, explains why placing drivers over building insulation is the best practice.
We are seeing some downlight manufacturers and importers claiming their LED drivers can be covered in building insulation.
Here at Home Lighting we insist that all our drivers should be located above any building insulation and there is a very good reason for this.
All drivers contain electronic components that are typically mounted on a PCB and contained in a housing. One of the most heat sensitive components is the capacitor which normally has a Tc of around 70-75°C.
The Tc is the critical maximum allowable operating temperature of the weakest component in the driver and in most cases is the capacitor. If this temperature is exceeded for extended periods, the capacitor will dry out, change value and then the circuit will fail.
To prove our point we tested a 10W LED downlight with remote driver that is typical of those available in the market today. The thermocouple was placed nearest to the Tc point (in this case 70°C) and we measured the temperature firstly with the driver located on top of the insulation in the Test Box, then secondly with the driver placed under the insulation.
Test Results: (corrected to an ambient temperature of 25°C)
On top of insulation Tc = 58.08°C
Under insulation Tc = 86.58°C
That’s a 28.5°C increase!
This will considerably reduce the lifetime of the driver and LEDs in the downlight.
You decide – are you happy to cover LED drivers with insulation?
Download LED Downlight Drivers – Over or Under Insulation Article
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