Arizona R-11 Electrical Residential

The main bonding jumper connects the grounded circuit conductor to the equipment grounding conductor at the service, while the system bonding jumper makes the same connection at a separately derived system (e.g., a transformer).

Overload heaters must be sized from the motor's actual nameplate ampere rating to protect the specific motor, whereas branch-circuit conductors and overcurrent protective devices are sized using the full-load current tables (NEC 430.248/430.250).

Feeder conductors are sized at 125% of the largest motor's FLC plus the sum of all other motors' FLCs, while the feeder OCPD is sized by taking the largest branch-circuit OCPD rating for any motor and adding the FLC of all other motors.

On construction sites, employers may use either GFCIs or an assured equipment grounding conductor program to protect employees from ground faults on branch circuits; they are alternative compliance methods.

Under an assured equipment grounding conductor program, fixed cord sets and receptacles not exposed to damage must be tested at intervals not exceeding 6 months, while those exposed to damage must be tested every 3 months.

Type NM cable is permitted for interior use in one- and two-family dwellings including attached/detached garages and storage buildings, whereas Type USE cable is identified for underground use only and shall not be used for interior wiring.

For 6 AWG or smaller, the grounded conductor must have a continuous white/gray outer finish or factory-applied stripes (field tape alone is not permitted), while for 4 AWG or larger, identification may be made at the time of installation by a distinctive white or gray marking or tape at its terminations.

The EGC is sized based on the rating or setting of the automatic overcurrent device ahead of the equipment (NEC Table 250.122), while the GEC is sized based on the largest ungrounded service conductor (NEC Table 250.66).

For single-phase circuits, I = (kW × 1000) ÷ (E × PF); for three-phase circuits, I = (kW × 1000) ÷ (E × PF × 1.73), where 1.73 (√3) accounts for the three-phase power relationship.

A multiwire branch circuit requires a means that simultaneously disconnects all ungrounded conductors at the point of origin (e.g., a 2-pole breaker or handle-tied single-pole breakers), whereas a standard branch circuit may use an individual single-pole breaker.

In a 120/208V three-phase system, phases are black (A), red (B), blue (C), neutral white/gray; in a 277/480V three-phase system, phases are brown (A), orange (B), yellow (C), neutral gray.

When 4 to 6 current-carrying conductors are in a raceway, ampacity must be reduced to 80% of the table value; with 3 or fewer current-carrying conductors, no adjustment factor is applied.