Pete, do you really think 15v to a lamp wont burn them out just as quick. Fact is if you are using a 22v tap you probably are hundreds of feet away and need it. It would be no difference if you were closer and need a 15v. That argument is weak, stick with the fact that 16,17,18,19.........30v is so much more dangerous than 14, and 15. The fact that lamps burn out has nothing to do with the higher taps as much as it does with an increase when you lose a lamp. 13, 14, and 15 v are capable of overloading a lamp just as 22v can. Its all in how you test and wire your system. An unliscensed contractor or homeowner should not be wiring our systems. We build them for the professional that should know what happens when you touch 2 sides of the cable togeather and also what happens when you stick your tounge on a frozen metal pole. But hey if you dont need 15v then more power to you, I have said it before and I will say it again, we make a UL1838 TF, we just dont sell many of them. Joey D.