As one of my teachers on “grounding systems” say’s: “The only way that you can separate to grounding systems is, if you place one of them on earth and the other one on the moon”. I agree, but this is one of the most frequent questions we get asked when we are inquired about grounding systems. The main thing is this: “you need to have ALL of your grounding systems connected together”, this is true because if you do not have them connected together, you can have grounding loops and in an event of a lightning storm your systems will not be at the same potential, causing that energy from a lightning strike enters trough your earth or neutral, causing damage’s to your electrical equipment and possible harmful injuries to the personal working at these sites.
You are going to hear all kinds of excuses for not connecting the systems together, mainly from the telecom and IT departments. This is cause mainly by misinformation and ignorance about grounding from the part of these engineers. You have to try and convince them that the only way that their systems would be secure is if they bond the grounding systems together.
What you need to explain to them?
This was the way that I was taught this years ago and it does not get any simpler terms than this. Tell them the following: Their “grounding system” is like a boat in open sea, if you have two separate systems, is like having two separate boats, etc. In the event of a “wave” (ex.: Transient, lightning strike, etc), it is preferable to have all your equipment in the same boat, this is because, this surges of energy can create a difference in potential, that can damage your other boat (or system), if they do not go up and down with at the same time with this wave. Do you get the picture?
Remember that grounding is the base of your Power Quality strategy. If your grounding is not good, all your other efforts would be in vain and your personal and equipment will not be safe.
If you have further questions on this or other PQ topics please send them to: firstname.lastname@example.org.