For group relamping a percentage of lamps to be regrouped per year is indicated. The number of lamps replaced is calculated by multiplying that percentage by the quantity of lamps in the system.

You can specify a relamping interval, so instead of relamping n% lamps every year, n% of lamps will be relamped every nth year. For example, if you enter an interval of 2, every other year, the percentage indicated will be replaced.