Here's a funny question that may help clarify things for anyone else who reads this thread, what does your cable/modem have to do with your power? In my neighborhood the cable company would not show up because of my power (or vice versa). They are two different entities. Also, were you having internet or cable issues before they showed up? If not, who gives a fuck if their equipment is having an issue? If their shit is not working they need to fix their stuff. You should feel free to do as you please as long as you're not having an issue and your grow isn't going to affect your shit. Just what I take from what you're saying. Hope it works out.