In order to evaluate the grounding systems at several facilities, I was asked to investigate several sites which have multiple buildings. To my surprise, none of the building appear to comply with Article 250.32. Since the building are 20+ years old, I wondered if the NEC code that was applicable at the time did not have the requirements of NEC 2014. I have gone back to older editions of the NEC, but can't seem to find an edition where grounding/bonding of building fed from another is not required. Am I headed in the right direction? Just hard for me to believe that all constrution observed was not originally constructed to code.
NEC 2014 Article 250.32
- Thread starter Clyde17
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- Occupation
- Licensed Electrician
Do they meet 250.32 (B) (1) Exception?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I believe the 2005 or 2008 NEC is where the change was made. Prior to that the detached structure could be run with no equipment grounding conductor as long as there was no metallic pathway between the buildings.
All the applications are 480V, 3-phase, 3-wire feeders with an EGC. Therefore, I don't believe 250.32.B Exception 1 applies.
- Occupation
- Licensed Electrician
What is it that is not compliant? Are you thinking there needs to be a neutral with the building feeders?
I think he's trying to say there is no GES at the feeder-supplied buildings. As far back as I recall, a GES at the supplied building is required for all except for one-circuit buildings.
- Occupation
- Licensed Electrician
Hmmm.... My mind did not even go there. Always had to have a GES as long as I have been alive.
- Location
- Bremerton, Washington
But many of us (including my self) mistakenly thought that you didn't need a GES if
1) the neutral was regrounded
2) a separate EGC was pulled and the neutral floated
But the NEC has required a GES at all separate buildings for protection from lighting. 40A or 400 A feeder, lightning does not know the difference.
1) the neutral was regrounded
2) a separate EGC was pulled and the neutral floated
But the NEC has required a GES at all separate buildings for protection from lighting. 40A or 400 A feeder, lightning does not know the difference.
Correct, I did not believe there was compliance with NEC 250.32 because I did not observe a Grounding electrode system at many of the buildings. I didn't know if the age of the systems may have come into play or if I wasn't understanding the exceptions correctly.
102 Inspector
Senior Member
- Location
- N/E Indiana
- Occupation
- Inspector- All facets
Could this be a situation where the grounding electrode system is something other than an 8 foot ground rod. Could it be connected to the metal water pipe and simply not notice during the first review. Not sure when ground rods became the normal application, but could pre-date them if other means are provided.
1999 edition is the oldest I have at my disposal. It required a supplementary electrode for water pipe even then... but not necessarily a ground rod, as is the case even today.
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