00crashtest
Senior Member
- Location
- California
- Occupation
- electrician trainee
In the 2017 Edition of the National Electric Code, (1) in (B) and (1) in (C) both in Section 250.32 specify, "An equipment grounding conductor, as described in 250.118, shall be run with the supply conductors and be connected to the building or structure disconnecting means and to the grounding electrode(s)." However, it does not specify whether they have to connect directly or indirectly. Furthermore, typically, the EGC is connected to the main bonding jumper (typically a neutral bus bar), which in turns connects to the GEC, which in turns connects to the grounding electrode(s). That means the EGC is indirectly connected to the grounding electrode(s). According to the standard practice of EGC installations, 250.32(B)(1) and 250.32(C)(1) allow indirect connections as much as direct connections.
250.130(A) also says that the EGC for grounded systems must be bonded to the GEC and system grounded conductor (neutral wire). Again, it does not specify whether of not the bonding has to be direct or indirect. Again, the standard EGC is bonded indirectly to both the GEC and system grounded conductor, because it first needs to go through the main bonding jumper. So, this effectively also allows indirect bonding as much as direct bonding.
So, is one allowed to connect an EGC directly to any GEC that connects to the main bonding jumper at the other end? This way, the EGC in indirectly connected with the disconnecting means, just like with the grounding electrode(s), GEC, and system grounded conductor. Furthermore, a GEC is electrically way better than a regular EGC because it has a way lower resistance and is tougher. That way, the section of the GEC between the EGC and main bonding jumper is not classified as an EGC for official purposes, just like the main bonding jumper, though they both in essence function as one.
For example, the GEC can be a standard structural metal frame of a building, which has practically zero resistance (practically infinitely higher current carrying capacity) compared to a normal wire, but does not qualify as an EGC under 250.118. That way, if one classifies in the plan for the frame as only a GEC, one can circumvent the requirement of 250.118 and the prohibition in 250.136(A) of the frame being used as an EGC, as well as save large amounts of money, if the equipment is directly connected to an EGC before being connected to a GEC on the way to the disconnecting means.
250.130(A) also says that the EGC for grounded systems must be bonded to the GEC and system grounded conductor (neutral wire). Again, it does not specify whether of not the bonding has to be direct or indirect. Again, the standard EGC is bonded indirectly to both the GEC and system grounded conductor, because it first needs to go through the main bonding jumper. So, this effectively also allows indirect bonding as much as direct bonding.
So, is one allowed to connect an EGC directly to any GEC that connects to the main bonding jumper at the other end? This way, the EGC in indirectly connected with the disconnecting means, just like with the grounding electrode(s), GEC, and system grounded conductor. Furthermore, a GEC is electrically way better than a regular EGC because it has a way lower resistance and is tougher. That way, the section of the GEC between the EGC and main bonding jumper is not classified as an EGC for official purposes, just like the main bonding jumper, though they both in essence function as one.
For example, the GEC can be a standard structural metal frame of a building, which has practically zero resistance (practically infinitely higher current carrying capacity) compared to a normal wire, but does not qualify as an EGC under 250.118. That way, if one classifies in the plan for the frame as only a GEC, one can circumvent the requirement of 250.118 and the prohibition in 250.136(A) of the frame being used as an EGC, as well as save large amounts of money, if the equipment is directly connected to an EGC before being connected to a GEC on the way to the disconnecting means.
