Parse time string to time

First, note that the cells in F5:F13 are formatted as Text prior to entry. This allows the times to contain leading zeros like "083000". Alternately, you can enter these time strings with a single quote at the start (') to force Excel to respect them as text.

Next, the time string contains 6 characters in the following format:

hhmmss // as text

This means the formula needs to pick up 2 characters each for hour, minute, and second. Working from the inside, out, this task is performed with the LEFT, MID, and RIGHT functions:

LEFT(E5,2) // get hh
MID(E5,3,2) // get mm
RIGHT(E5,2) // get ss

Each of the function returns a result directly to the TIME function. In E9, we have:

041055

So the result inside TIME looks like this:

=TIME("04","10","55")

The TIME function then quietly handles the text-to-number conversion and returns a valid time:

04:10:55

Representing 4 hours, 10 minutes, and 55 seconds.

With a 4-character time string

The formula in C5 is meant to handle only a 4 character time string (hours and minutes), so the structure is a bit simpler. We simply hardcode the value for seconds into the TIME function as zero:

=TIME(LEFT(B5,2),MID(B5,3,2),0)