The answer depends on which version of the electrical code is currently in use in your area. The more recent versions of the code (2008 and newer) allow you to place a single loop of #8 copper wire around the outside of the pool and below the pavers (18-24" from the water and 4-6" below sub-grade. Older versions of the code require a full copper grid underneath everything within 3 feet of the water. Different areas update which version of the code they are using at different times, and so it is possible, though no longer all that likely, that your area is using the older version. It is best to ask your inspector for clarification.