On the Technician class test there is a question which says, “What is the purpose of a fuse in an electrical circuit?” and the answer is, “To interrupt power in case of overload.” In the Gordon West Technician Class Q And A book it says, in the added notes, “Place the fuse as close to the battery as possible.” (Page 162). That is good advice because if for any reason the positive wire’s insulation is damaged and the wire touches the chassis or engine (a hot manifold is a frequent cause of this problem) then it will blow the fuse if it is close to the battery but not if it is between the radio and the short.
On that same page it shows a schematic of an installation and it shows a fuse in the negative line. Many hams think that is unnecessary because you will not cause a short if the negative wire touches the metal of the vehicle. So why place a fuse in this line?
Posted by 9w2bba 
