It doesn't have to do with protected area, but the ability to keep the runway in sight.
Min meteorological visibility for cat C aircraft is 2400 meters.
With 3 sec
pr 100 feet, you are quickly at the limit, as can be seen from the example below:
Downwind:
If going 180 knots ground speed, that is 3 nm
pr min.
Min circling alt is 600 feet = 18 secs
18/60 sec x 3 nm/min = 0.9 nm = 1666 m
Turn radium (30 deg bank):
r = V^2 / G x Tan AoB
If V = 180 knots = 5556 m/s
g = 9.80665
Tan 30 deg = 0,577
= 981 m
Max distance from runway:
1666 + 981 = 2647
So you have to go slower that 180 knots
ground speed or increase your minima respectively.