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Dimmer De-Rating Factors

Dimmer de-rating factors:

Dimmers will need to be de-rated or have their maximum wattage reduced, for a variety of factors.

Per manufactures instructions.
When multiple dimmers are used in the same switch box.
When the ambient temperatures exceed the manufactures limits.

How much you de-rate will be determined by manufactures recommendations, usually 20% per each additional dimmer.

Example:
3 dimmers in one box each rated at 600watts.

600 watts x 80% =480 watts

480 watts de-rated by two additional dimmers of

Equal value: 20% + 20% = 40% reduction or a 60%

Allowable rating of each dimmer

480 watts x 60% = 288 watts per each dimmer.

In order to operate any series of lamps that exceed 288 watts, in this set up you will need larger dimmers.

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