ECN Forum Forums Technical Discussion Electrical Theory and Applications Landscape lights vs. Lightning surge

Hello All! I have 2 customers whose 12V landscape lights keep prematurely burning out. I examined some of the bulbs and they were completely blackened. Both customers live on top of hills, both have water wells withing 200 ft. of residence. Both customers 12V landscape transformers are GFCI protected, which never tripped. Any ideas would be appreciated.