Better Surge Protection Extends URD Cable Life

Many utilities are replacing URD cables after 10 to 15 years of service despite an original life expectancy of three times that. There is compelling evidence that part, at least, of the problem is lightning surges. Test data confirms that impulse voltages less than the breakdown value can cause partial breakdown and eventual failure. The progressive weakening of cable insulation by these surges can be greatly retarded by using surge arresters with the superior protective characteristics of zinc oxide technology. These same arresters protect in the conventional manner. Field experience suggests that protective margins of at least 100 percent are needed based on rated cable BIL. The zinc oxide arresters can provide this.