Heat generated by electrical equipment operating under load will prevent the accumulation of condensation. After the equipment has been switched off however it cools down and gradually adapts to the ambient temperature, thus dropping below the dew point. This is the signal that triggers the heater! These sources of heat prevent the formation of condensation by raising the internal temperature a few degrees above the ambient temperature. In the interest of evenly distributing the heat, we recommend that the requirement of heating capacity is divided among several small heaters.