If the run is much too short:
Check the power supply settings!
If the conditions are no longer understandable, then a run log should be made (next time): with Set and Read!). So you can understand what happened....
Remedy: check the run and keep a record.
The run is a bit too short:
In EDC’s SDS buffer-system the SDS runs behind the Bromophenolblue (BPB). This means: Stopping the run with the BPB will left ~1.5 cm SDS in the separation gel.
Remedy: let the SDS run out of the gel and use the separation distance for your proteins by optimized shutdown:
a) You can see the backside of the SDS-zone:
mark it with Conchenille in the sample buffer.
Let it out in the anodal strip, then shutdown.
b) Use a prestained standard and run it till the 10 kDa stays just before the anodal strip.
See also 2D-trouble-shooting: “optimal shutdown”