Penalty enforcement???

[foureyedzebra]

2nd and 10 @ A 20.
A28 takes a hand off and advances to the 50 and is tackled.
During A28's run, A19 clips B50 @ the A 32

1. Before A28 has made the line to gain.
2. After A28 has made the line to gain.

Team B accepts the penalty. What is the resulting down and distance?

[TXMike]

does not matter if A28 "made the LTG".  2d and 13 at the A17 in both cases

[El Macman]

Here is why:
-The foul is a "Basic Spot Enforcement" foul, i.e., it is penalized according to the 3 & 1 Principle, relative to the Basic Spot for that foul.
-The foul occurred during a running play, and the related run ended beyond the neutral zone, so the the Basic Spot is the end of the related run, which is the 50.
-The foul occurred behind the Basic Spot.
-The foul was by the offense during the related run.
-By the 3 & 1 Principle, fouls behind the Basic Spot by the offense are penalized from the Spot of the Foul.
-The exception for fouls by the offense behind the neutral zone obviously does not apply.
-The distance penalty is 15 yards.
-Penalizing 15 yards from the Spot of the Foul - the A-32 - leaves the ball on the A-17.
-The down is repeated - 2nd down.
-Thus, A, 2/13, A-17.
-Assuming the ball carrier was tackled inbounds, the clocks start on the RFP signal (25 on the play clock).

In no case does the timing of a foul during a running play affect the enforcement spot. The line-to-gain is not considered until after the penalty is enforced. If the ball is behind the LTG after the penalty, then the down is repeated (unless the penalty includes "loss of down," then it will be the next down in the series). If the ball is beyond the LTG after the penalty, then Team A gets a new series (first down), even if the penalty includes "loss of down."

[Hawkeye]

Some rule references so you can find it in the book:

2-25-10, 2-33, 9-1-Penalty, 9-1-5, 10-2-2-d-1-b, 10-2-2-c-1, 5-2-3-a

If the foul in your play had occurred at the A-48 instead of the A-32, then the result would be A 1/10 at the A-33, since after enforcement, the ball is beyond team A's line to gain (5-2-2-a).