Grounding(electrical)

Hi peeps,

i recently got schooled on how to properly ground our equipment here in the office. Basically a contractor installed a ground wire on our equipment racks(with pcs, switches, etc). They used a VOM to check for grounding, and found that some equipment were OK, some were not. They suggested that we run ground wires to each equipment to be sure.

Some questions:

1. Sabi nung isang electrician, we just need to ground one server/switch, then OK na daw. But nagaground pa rin when we tested the other equipment. Need ba talaga maglagay ng ground wire per equipment?

2. Do i need metal to metal contact, i.e. metal covering to ground wire? i'm getting conflicting answers, sabi ng iba need pang iscrape yung paint para me contact, sabi naman ng iba hindi na kelangan.

3. The contractor mentioned that they somehow connected the ground wire to sprinkler pipes, in addition to attaching it to the building/floor's earth ground, for additional safety daw. Tama ba yung ganito?

4. We have a few servers with aluminum casing, no paint or coating. Can we ground it by attaching the ground wire directly onto the casing?


tia