I don't know if this is a repost, don't have time to read through all the searches, but i tried to.

So on my second run through the game decided to go with the Legion, and at Helios One i used Archimedes to obliterate the troops, then i decided to take my loot and sell it over at the BoS bunker. While i didn't earned any bad reputation with them the BoS turned hostile, Why? I remember now seeing in a terminal that when Acrhimedes is activated it causes a 2-3 minute brownout in the area, namely Black Mountain and Hidden Valley, could that be it?