On a PMA system the reg/rec should be wired straight to the battery. Then from the Battery/PMA to the rest of bike. The way your first diagram shows.
With the PMA wired in after the fuse, as in others posted, if the fuse blows the battery gets eliminated from the PMA circuit. This unbalances this circuit and the reg goes wild and can send power surges into the system exceeding 20 volts. This happens because the power floing from the PMA bypasses the fuse. Not A good thing.
In your original diagram if the fuse blows all power stops flowing from the battery/PMA. This is a good thing.
Leo
With the PMA wired in after the fuse, as in others posted, if the fuse blows the battery gets eliminated from the PMA circuit. This unbalances this circuit and the reg goes wild and can send power surges into the system exceeding 20 volts. This happens because the power floing from the PMA bypasses the fuse. Not A good thing.
In your original diagram if the fuse blows all power stops flowing from the battery/PMA. This is a good thing.
Leo