Services, Grounding & BondingQuestion 57 of 120
On the load side of the service disconnecting means, what is the general rule for using the grounded neutral conductor to ground equipment enclosures?
a.It is permitted only in dwelling units
b.It is permitted if the neutral is at least 6 AWG copper
c.It is permitted in any panelboard fed from the service
d.It is not permitted; a separate equipment grounding conductor must be used
Explanation
Downstream of the service disconnect the neutral and the equipment grounding conductor must be kept separate so that normal load current does not travel on enclosures and raceways. Bonding them together at a subpanel creates parallel neutral paths and objectionable current, and neither conductor size nor occupancy type changes this general prohibition.
Law Reference: 2023 NEC §250.142(B)Practice all 120 questions free — no signup required.
Related questions on this topic
- What is the minimum service disconnecting means rating for a one-family dwelling?
- What is the minimum clearance above a residential driveway for overhead service conductors limited to 150 volts to ground?
- Overhead service conductors must maintain what minimum clearance from a window that is designed to be opened?
- Ground-fault protection of equipment is required for a solidly grounded wye service with more than 150 volts to ground when the disconnect is rated at least what value?
- How must a panelboard be protected against overcurrent?
- A dry-type transformer rated 112.5 kVA or less is installed indoors. What is the minimum separation from combustible material unless it is separated by a fire-resistant heat-insulating barrier?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against Journeyman Electrician Licensing Exam (NEC-based) · How we review