I'm carrying out some inspection and testing this morning. I've come across something new to me. I'm a workshop they have a 3 phase DB which is ONLY supplied from a generator. The site only had a single phase supply and therefore when they need to use 3 phase equipment they simply switch on the genny to do so. Are there any precautions I need to consider before testing? All the dead tests can be carried out as normal but when it comes to the live tests im thinking there could be problems. Earthing system? High Ze readings?