Grounding, Bonding and Neutral Reference Diagrams
Distinguish grounded, equipment grounding, bonding, and grounding electrode conductors using a scoped service-and-feeder diagram and terminology guide.
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Different conductor functions
Grounded conductor, equipment grounding conductor, bonding jumper, and grounding electrode conductor describe different functions. Similar bus bars or conductor colors do not make those functions interchangeable.
| Term | Reference function | Common confusion |
|---|---|---|
| Grounded conductor / neutral where applicable | A system conductor intentionally grounded; a neutral has the defined relationship to the system | It is not another name for an equipment grounding conductor. |
| Equipment grounding conductor (EGC) | Part of the equipment grounding/bonding path used for fault-current return | Not an ordinary load-current return conductor. |
| Bonding jumper / bonding connection | A connection joining conductive parts for the applicable bonding function | Not automatically permitted at every downstream neutral bus. |
| Grounding electrode conductor (GEC) | The conductor connecting the applicable grounded/bonded system point to the grounding electrode system | Not a substitute for the required equipment fault-current return path. |
| Grounding electrode | The electrode connection to earth in the applicable system | Earth alone is not the normal intended fault-clearing path for an equipment circuit. |
Scoped service and feeder concept
In the illustrated arrangement, the downstream neutral path is separate from the equipment path so ordinary neutral current is not deliberately routed through equipment bonding paths. The governing bonding location comes from the actual system and applicable requirements; a label such as “main” or “subpanel” alone does not settle every case.
Check the actual system
- Establish whether the equipment is service equipment, a feeder-supplied enclosure, a separately derived source, or another special arrangement.
- Read the source, transfer, and equipment diagrams and the locally adopted requirements.
- Identify neutral isolation, equipment bonding, any system bonding jumper, and electrode-system connections as separate items.
- Have uncertain existing arrangements reviewed through the authorized project process instead of copying this simplified sketch.
Generator switched-neutral arrangements, separately derived transformers, parallel paths, and other special cases need their own review. This page does not instruct a user to add or remove a bonding screw, choose conductor size, or repair an energized panel.
Use the existing EGC, GEC, and bonding-jumper references only for their own scoped sizing tasks. Check local code adoption separately.