Most Crestron equipment? (except for power amplifiers) today have switching power supplies where the neutral/line are completely isolated ? from ground and can tolerant quite a bit of voltage on the ground with respect to neutral (as long as they aren't connected to anything else).? It depends on the power supply and the load but I see a lot of stuff that will operated all the way down to 60VAC line.? A bigger issue is brown outs and power glitches.? Some stuff can tolerate a brown out of any level and not lock up.? More the normal is some equipment will lock up with a power glitch and require a hard boot to restore operation.? But on the worst end, some stuff that I work on will literally blow up with a very expensive repair if the line voltage drops below 110V. I don't think you will find a spec more detailed than the range of voltage operation.? For example, my laptop power supply is spec to operate on anything between 100 to 240VAC.
If you lift the ground on a piece of equipment, many, if not most, will have about half the mains line voltage (60VAC in the USA) on the ground pin and they will continue to operate properly.? The issues however can occur when you start connection stuff together.? It is the ground different between different pieces of equipment that will cause the damage.
For example, we had a Samsung TV that just had a 2 pin power plug.? If you measured the case of the TV to the ground pin in the wall outlet, it was 60VAC.? The current however on the ground was quite low so it wouldn't even shock you.? And the TV worked fine too.? Connect anything to it that was grounded and the voltage drop to zero. But when you connect the HDMI cable from a Control4 room box to it, the 60VAC ground voltage blew up the Control4 receiver.??? We landed up connecting a ground wire between the TV chassis and the wall outlet ground and had no more issues with Control4 blowing up.
At another employer I work for, 90% of the HDMI boards we replace? in receivers have blown up CBL/SAT HDMI inputs.? The reason is many Cable and Satellite systems are grounded outside the house at a different grounding? point that the power line (usually near the power pole) -- that is what code requires too.? Ideally, you want your cable satellite provider to also ground the cable to the electrical? panel when it comes in the house.? If it is not, that is when the CBL/SAT inputs get zapped.
