phpMyAdmin is a tool written in php intended to handle administration of MySQL servers over the web interface.
When trying to import large SQL dumps you might see following message:
Maximum execution time of 300 seconds exceeded
If you are running on local host or host you manage the solution is to edit \phpmyadmin\libraries\config.default.php file and change
$cfg['ExecTimeLimit'] = 300;
$cfg['ExecTimeLimit'] = 0;
This will allow you to remove the limit.
In case you do not have access to configuration file (and your provider does not want to apply this change even if you ask nicely) only solution is to split one large file to several smaller files using text editor and add them one by one.
Note: The size of the file varies from host to host and should be determined by the method of trial and errors.