I think your floating secondary is very dangerous. The voltage can drift all over the place with respect to the rest of the household wiring. This can be a real problem if you connect some components to the floating conditioned supply and some to household wiring. You should read applicable sections of NEC article 250 on grounding or get advice from an electrician or your town's building department electrical inspector. Look for specific information about grounded electrodes and grounding neutrals. IMO, what you should do is tie the neutral of the primary and one of the secondar legs together. this will bring the neutral through to the other side and establish the same reference zero voltage point for the conditioned side of the transformer as the rest of the system. BTW, it is illegal to use a circuit breaker or fuse on the neutral leg so be sure it's on the hot side. In case you haven't done it, you need to bring the safety ground through to the ground leads for your receptacles as well. They should be securely bonded. Get advice from expert help if you do not understand this.