Effects of thermal insulation on electrical connections and outlet boxes

When residential walls are retrofitted with foamed-in urea formaldehyde or blown-in cellulose thermal insulations, the insulation may enter electrical outlet and switch boxes. The effects of these thermal insulations on the durability of electrical components were studied. These studies were carried out at 44, 75, and 96 percent relative humidities with test periods between one and twelve months. Laboratory test methods were developed and tests performed to determine the electrical and corrosive effects of urea formaldehyde and cellulose thermal insulation contained in electrical outlet and switch boxes.