In this paper, we show how short-circuits on FPGAs can be caused by partial runtime reconfiguration. Short-circuit can even occur on FPGAs that do not offer any tristate resources just by using off the shelf vendor tools without any bitstream manipulation. The duration of the here presented short-circuits ranges from short spikes up to persistent short-circuits that remain active during runtime. Short-circuits will result in increased current consumption and can thus harm the system and must therefore be prevented. An algorithm is derived that detects whether configuration data will cause short-circuits. We implemented this algorithm in a bitstream scanner that can also be used in systems at runtime.