You guys have covered the issue of a lightning strike affecting the power to the devices - but you must also consider a more vulnerable issue - the network connection. I have seen lightening strikes wipe out entire networks through the ethernet cables initiating through the internet connection. A voltage spike to the network connection to a miner will fry the controller. The best way to protect from this is to use a fiber link somewhere between the Internet connection and the miner farm. Electric surges cannot pass through fiber.
How to use a fibre link? Can it be used in a cable modem setup which uses cat 6 cables? I am not using fibre internet.
I assume he's talking about using a media converter, going from UTP to fiber (and back) is common in the structured cabling world. I haven't used one in a long time but they even have coax to fiber media converters if you have coax and you wanted to protect the modem as well.
If this is a "home" type set up I would avoid the media converters and would just get an inline ethernet surge protector. Avoid the real cheap ones make sure to look at ones that are rated for "lightning protection".
Something like this one:
https://www.amazon.ca/Ethernet-Surge-Protector-Gigabit-1000Mbs/dp/B00805VUD8Please note I have never used that actual product I just did a quick google search on ethernet cable surge protection and that was the first one from amazon that popped up! It is just an example, do your own research as that one is probably overkill for a home miner.
This looks good but can I guess I cant just attach the green ground wire to my metal shelf.
Grounding is not convenient.