At installing of dimmers it have to be considered that the devices are producing loss-heat. For leading edge dimmers it is about 1,3% and for trailing edge dimmers it is about 2,5-3% (!!!) of the controlled power. The indicated maximum dimmer load is for surrounding temperature of 35ºC, therefore the allowable load highly descends at temperatures more than 35ºC (see diagramm!). In small construction units (modular installation devices / DIN rail) and various devices installed in a covered distribution cabinet, the surrounding temperature can easily come to improper operation conditions. Enough ventilation and proper arrangement of the devices are therefore necessary, e.g. mounting 2 devices in full capacity should not be done to close to each other, specially the device underneath will heat the upper device additionally and therefore produce a thermal overload. The more devices located at the distribution cabinet the more thermal problems may occur, therefore special attention is needed to avoid problems and early failure of devices.

The maximum load is given on the dimmer.
At a higher surrounding temperature a
reduction is needed in accordance
with the diagram.


Surrounding temperature ºC

by 50 ºC surrounding temperature
reduced to the permitted load of 57%.
by 60 ºC surrounding temperature
reduced to the permitted load of 28%.

DIMMERS CAPACITY LOAD

In principle all dimmers can be constanly operated at its maximum load, however it is necessary to avoid longer thermal overload (see the above section).
It also have to be considered that the allowable capacity load is based on the type of the load, the load factor 1 is only given on 230V- incandescent lamps. The allowable loads for dimmers are:

1) incandescent lamps (not low voltage)
2) fluorescent lamps with conventional ballasts
3) fluorescent lamps with eletronis ballasts
4) low voltage halogen lamps (through transformers)