Arizona R-11 Electrical Residential

Feeder conductors must be sized at 125% of the largest motor's full-load current plus 100% of the FLCs of all other motors, while the maximum feeder overcurrent device rating is the largest motor's branch-circuit overcurrent device rating plus the full-load currents of all other motors.

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

Three-phase calculations include the 1.73 multiplier (square root of 3) — used in the denominator for amperes and in place of the factor 2 in voltage drop — while single-phase calculations omit 1.73 and use the factor 2 for voltage drop (the factor 2 alone applies to two-phase four-wire circuits).

AC formulas include power factor (and 1.73 for three phase) because voltage and current can be out of phase, while DC formulas use no power factor, no factor of 2, and no 1.73 (e.g., I = (kW × 1000) ÷ E and HP = (E × I × %EFF) ÷ 746).

Table 5 gives the required area of each individual conductor, while Table 4 gives the usable area within the selected conduit or tubing; both must be used together (instead of Annex C) when conductors are of different sizes or insulation types.

THHN is rated 90°C and permitted in dry and damp locations only, while TW is a moisture-resistant thermoplastic rated 60°C and suitable for dry and wet locations (THW and RHW are 75°C, dry and wet).

Conductors 6 AWG and smaller must be factory identified (continuous white or gray outer finish or three continuous white/gray stripes on other than green) and may not be identified solely by field-applied marking tape, whereas 4 AWG and larger may be identified at installation by a distinctive white or gray marking encircling the conductor at its terminations.

Overload heater elements must be sized from the actual motor nameplate amperes, while branch-circuit conductors and overcurrent devices are sized from the full-load current tables.

Voltage of a circuit is the greatest rms difference of potential between any two conductors of the circuit (240 volts on a 120/240-volt circuit), while voltage to ground is the separately defined measurement from an ungrounded conductor to ground (120 volts).

Per 250.4(A)(5) the earth shall not be considered an effective ground-fault current path because its resistance is too high; the effective path must be a low-impedance circuit able to safely carry the maximum ground-fault current to the supply source.

Type NM (with NMC and NMS) is permitted in one- and two-family dwellings and their attached or detached garages and storage buildings, while Type USE is identified for underground use and shall not be used for interior wiring.

The grounding electrode conductor is sized from the largest ungrounded conductor (or equivalent area for parallel conductors), while the equipment grounding conductor is sized from the rating or setting of the automatic overcurrent device ahead of the equipment.

The power supply output circuits must be rated 25 amperes maximum under all load conditions, while the Article 411 system itself must be supplied from a branch circuit rated 20 amperes maximum.

On a fuse current-limitation chart, peak let-through current corresponds to the mechanical forces exerted on conductors and equipment, while the apparent prospective RMS symmetrical value corresponds to the heating effect (clearing time being a separate characteristic, less than ½ cycle in the current-limiting range).