Use the Null Source Control if you don't want to check a Source Control repository for changes. In this instance you would always want to either use a 'Force Build' Trigger or always manually start builds, from the Web Dashboard or CCTray.

Strictly speaking, this element isn't required. The build server will behave the same way if there are no Source Control Blocks. Still, it's useful to include this in configuration files to make it clear.

Example:

<sourcecontrol type="nullSourceControl" />