grounding system maintenance and testing

[jmccloud]

I work at a site with Class 1 Div 1 and Class 1 Div 2 locations. Ensuring that the equipment is grounded and all of the static is removed from any equipment with flammable liquids has been a topic of discussion for some time now. I was asked to look into testing our grounding system and i cant find any code related to how often it should be done. In article 205.5 of the NFPA 70E the section says the grounding and bonding systems shall be maintained. Would there be another code book that would have more information on this subject with a more specific answer?

 

[rbalex]

I believe you meant NFPA 70E, Section 205.6. See NFPA 70E, Section 250.3 and its Informational Note for further guidance. Also see NFPA 77.

The frequency of periodic testing is generally dependent on the nature of the possible corrosive conditions of the installation. I have seen facilities, especially with high H₂S present, where copper was literally falling apart. I have seen other, rather benign facilities, where the grounding/bonding was sound for well over 25 years. Visual inspection is usually recommended as part of the overall routine maintenance schedule. More frequent inspection and testing may be warranted depending on conditions.

 

[jmccloud]

Thank you I will have to get a copy of the NFPA 77 book now. Yet another book to add to the collection.
Thanks again

 

[nollij]

API 2003 may be a good reference as well if you work in the petrochemical industry.

Our facility uses a PM to check bonding (for static electricity and lightning). Notably, the value you are looking for isn't necessarily XX Ohms but whether the value would indicate that the connections/conductors are degrading.