......and that's with a capital IF because the X-5 normally does not have much problem along these lines.

But, if you experience outside RF interference, there are several things you can try.

First off, the ground balance will usually have little or no effect on RF interference. The problem with 60 cycle electric lines is that they interfer across a wide spectrum of multiples both above and below their own "frequency".

Next, just reduce the sensitivity to help eliminate the interference. In most cases, this will be sufficient. If not, try the beach mode. A higher discrimination level also may or may not help with external RF interference. That's something you will just have to experiment with in your own location.

Another thing that many forget is that the coil of the detector is nothing more than an "antenna", and the larger it is, the more it receives. Try a smaller coil, and that will also help in most situations to some extent.

Most of the larger transmission lines are the ones that really cause problems, more so than the little service lines. Sometimes the lines are not as much of a problem as nearby transformers. Try moving away from the transformer itself.

One season in southern Arizona, some of the guys were using Minelab PI machines that were extremely sensitive to external RF, so much so that if two of the Minelab guys got separated, they just raised the detector coil and spun it around in a circle until it detected the signal of the other machine..... kinda like a directional homing antenna.

Ralph