(a) In any residential district, no fence or portion thereof shall exist within two feet of the front or any street lot line.
(b) In any residential district, no fence shall be erected upon a vacant lot which unreasonably obstructs the front yard sight line or is otherwise hazardous.
(c) Fences in residential districts shall not be more than four feet in height in the required front yard and not more than six feet in height in all other areas unless otherwise permitted.
(d) All fences in nonresidential districts shall not be more than seven feet in height unless otherwise permitted.
(e) Fences or walls required to surround and/or enclose public utility installations shall not be limited as to height in any district.