My company does audio visual services. When we use a single 120/208 VAC Three-phase "Y" power source for lighting, audio and video we get noise caused by the lighting dimmers injected into the audio and video. We purchased a 30 KVA Isolation transformer. We tie-in power and run it first to the lighting dimmers then put the isolation transformer in line before powering up the audio and video equipment. It eliminates buzz in the audio and interference lines in the video. The transformer has three hot and one ground connections on the input side (no neutral on the input side) and on the output side a ground, neutral and three hots. Is it correct for me to wire the input ground to the transformer case and wire the output ground to the output neutral and not connect the output neutral and ground to the case or input ground?