During manual installation of lamps remember that water and electricity are very dangerous things to mix. In order to avoid problems and to have a long lasting, functional, and safe result, the lighting needs to have a high level of inner isolation from moisture, mechanical issues and dust. These technical characteristics are found in manuals and other documentations which come with the equipment. During your purchase of the lights pay attention to a characteristic named Index of Protection (abbreviated IP). This index should be at least 68. The first number in the index determines the level of resistance to dust and small objects. The number 6 guarantees complete protection from outside elements. The second number in the index shows the resistance to water that the gadget has. The eighth level means the object can be submersed in water without a time constraint attached. While buying illumination for your pool consider the importance of not electrically shocking anyone in the pool. In order to avoid this make sure all wires, lamps, and gadgets are properly sealed. At no time should live wires be making contact with the water. As an example of a precaution, low power systems such as some 50 watt underwater lighting lamps are placed only in Jacuzzis and similar pools where the maximum depth is about a meter. Power for illuminating large pools is slightly different, 100 Watts will be enough for almost 12 square meters of the pool, and a 300 Watt system will light up to 20 square meters.