Metal Enclosure Grounding

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YoSam

Member
Location
Houston
Occupation
QC Div. Manager
We have a Solar project that contains 209 POE Metal Enclosures. I think a EGC should be connected to the metal enclosure but find NEC confusing regarding the grounding. CM states ground is connected to din rail. Wouldn't that be considered a floating ground? Below are pictures sent to me by the CM explaining his thought process as well as the engineering design. Looking for an answer to supply. If the CM and design are correct, so be it.
Thanks

CM: Below is picture of POE enclosure and how it's connected to ground.
POE001.png
Routing of the conductors
POE002.png
Auxiliary Panel connection location for tying to ground grid.
POE003.png
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I'm pretty sure that those DIN rail EGC terminals actually connect to the din rail so it is bonded to the enclosure. Maybe industrial control cabinets do require an external bonding jumper. Look at the photo in the link below and you can see a metal tab to the DIN rail. And it says this:
Product Description
These grounding blocks mount onto DIN rails to terminate ground connections and safely discharge excess electricity within an enclosed panel. Also known as earth terminal blocks, they have yellow and/or green housing and are secured to DIN rails using a mechanical screw-clamp. Once connected, the DIN rail acts like a busbar and distributes a ground connection to other terminals touching the same rail.
Click to expand...

 
B

BillyMac59

Senior Member
Location
Wasaga Beach, Ontario
Occupation
Industrial Electrician
The grounding terminal block is a legit way of establishing a ground path. In the example shown, if one assumes the DIN rail is fastened to the panel's backplane with threaded metal screws/bolts and the backplane is secured to the panel and the panel is grounded, then a path to ground exists.
 
J

jap

Senior Member
Occupation
Electrician
Most enclosures we use have a painted back plate.
We'd take a bonding jumper from the den rail grounding block to the back plate mounting stud just for good measure.

Jap>
 
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