Other than making sure all of the negative terminals are common to the power supplies, is there a do's and dont's guide to adding additional power to an M1? Specifically adding power to ELKDBH's. I plan on using ELK 4 amp power supplies. What happens if a power supply fails does it take the whole system down? The installation is an approximately 10,000 square foot house, 8 keypads, lots of peripherals, etc.