– Polywater Duct Block Prevents Ice Formation –
The power stopped flowing from a large solar array at a Midwestern international airport. While investigating the failure, a combiner box full of ice was discovered. Water (and water vapor) had entered the box through the underground conduit system. The water had frozen during the cold temperatures. Click on (enlarge) the picture below to get a better look.
Water (and ice) should be kept out of combiners, inverters, switchgear or transformers at solar facilities. Moisture can cause shorts, fires, explosions and equipment failure.
A quality duct block will block water, even water at significant pressure. But, many of the traditional duct block materials used in electrical construction are minimally effective. Duct putty and aerosol expanding foams (“open” cell foams) will not hold water head pressure. Over time, the putty sags and dries out. The foams leak through their open cell structure. Neither will meet the NEC code performance requirements for sealing conduit raceways.
Polywater® FST™ foam duct sealant is a two-part foam that expands with a closed-cell stucture. The robust, cured block can hold back significant water head pressure. Prevent water entry, and there is no problem. The duct putty was removed and FST™ was installed at this airport, and the water issues went away. See the product link below to find out more about the advantages of using and specifying Polywater® FST™ Duct Block.