Grounding/Equipotential bonding systems

General Discussion
#1

Hello experts,

Based on this: ESD S20.20 8.1: …“An implementing process shall be selected from Table 1”.

Could you correct me if I’m wrong when selecting either one of the 3 (I guess I’m confused about TR53 same topic for non-monitored personnel wrist strap method).

  1. When selecting Equipment Grounding Conductor: Measuring with a DC ohmmeter from an ESD grounding cord to the outlet ground - [Basically no auxiliary ground system exists].
  2. When selecting Auxiliary Ground: This is when companies more grounding systems for the ESD program, we want to measure the difference between those 2 systems, same DC ohmmeter, from ground A to ground Auxiliary.
  3. When selecting Equipotential bonding: ESD items vs ground [ohms] verification.

Can we do internally those initial verifications? any recommended template?
According to ESD we just need initial verification, is this correct?
I appreciate all details to fully understand this

Thank you

#2

Santiago,

I don’t have much experience with setting up a grounding/equipotential bonding system as all the places I have worked are in the US and the electrical code here is sufficient to cover this. If you are also in the US as your profile states, then as long as the facility you are at was set up per the electrical codes you should be fine. Most places would fall under the Equipment Grounding Conductor category although some places use an Auxiliary Ground. If you are working in a place where access to the Equipment Grounding Conductor or Auxiliary Ground is not possible (like an airplace, ship, middle of a large factory floor, etc.), you would use Equipotential Bonding and ensure any ESD control items are connected so that they are all < 10^9 ohms to each other.

This test only needs to be done once unless changes have occurred in the electrical grounding system.

#3

The reason why the grouding system is only tested once is due to the fact that all other testing, worksurfaces, chairs, floors, mobil carts are all tested point to ground. In this case, the connection to ground is always being tested with the compliance verificaiton plan.
If that measurement fails, then you may have to test the ground connection to see where the failure occures.

1 Like
#4

@AndyN @JohnK , thank you so much!, very clear!

In the scenario where:

  • The electrical outlets are connected to the main panel and the main panel is connected to a grounding rod
  • The floor is connected to copper strips and the strips are connected to building columns

does it count as auxiliary ground? (in general, we follow electrical code, I’m in US), does it matter in this case?

Thanks

#5

By definition, yes that would be considered an auxilary ground. I would be surprised if there was any resistance between the two.

#6

Thank you very much!