Make sure if you are grounding to an I beam that you actually verify that it is an effective ground, also take the time to scrape the paint off of it for your connector. A bad ground is worse than no ground at all. For some reason in todays telecom industry very few people have the absolute importance of grounding in their mentality. It is not just an inconvenient hum on the line...its very dangerous (lightning etc) to have a poor or non-existent ground.

Don't get all sweaty and lean on the block...it tingles a bit!