I called the manufactures rep. because in their equipment cut sheet for a hot water tank was 20A-2p c/b for 4160 watt 208v. I explained to her that a good engineering practice is that most c/b should be loaded at 80% of their rating. Can I use a 25A c/b. She said that the unit is UL rated non-continuous so that 20A was all it needed. She also mention that breakers in the last nine years have changed so that you can load them up to 100%. I heard of 100% breakers but don't you have to spec them for the equipment or job. Does all breaker now capable of 100% load?