grounding of seperately derived system

[Michael Poggenpohl]

I work at a factory that the in house engineers donot bond the transformers to the steel columns that they sit next to or any of the equipment that sits on the floor. Their reasoning is if they get a short they donot want an employee who is leaning against the column to get shocked. They also state that the equipment ground on the primary side of the transformer is the only ground needed for the equipment since it is going back to the distribution center. Second concern, they have a huge ground loop under the dirt on property that they use for not only lightning protection, but also for equipment grounding electrode which they than bond equipment and the building to. The reasoning is that the loop takes the unwanted electricity to ground and protects the equipment which is very sensitive to outside electrical noise. Everything that I have read and installed from other projects go against their thinking what do you say. Thank You

 

[charlie b]

Your in house engineers are in need of a bit of continuing education effort. But I am not certain, in your first question, whether you are talking about bonding the case of the transformer, or the center/neutral point of the secondary windings. In your second question, the grounding electrode system that serves lightning protection is required to be bonded to the grounding electrode system that serves the power distribution system. But if your in house engineers are talking about that system in terms of taking unwanted electricity away, sending it to the planet where it can no longer do anyone any harm, then please reread the first sentence in this post (and invite them to do the same)