304.4

1 Awg

A 150-Amp, 120/208-volt, 3Ø, 4-wire service consists of three 1/0 AWG ungrounded conductors and one grounded conductor. The smallest grounded conductor that can be installed for this service is ___ AWG where the neutral load is expected to be 120 amps.

1/0

A 208/120-volt, 3-ph, 4-wire panelboard will be fed with one conduit. This service panel contains a 350-Amp main breaker. The conductors supplying the service will consist of three 500 kcmil ungrounded conductors (one for AØ, one for BØ, and one for CØ) plus a grounded conductor. The calculated neutral load is 80 amps. The smallest neutral that can be run is a ___ AWG.

2/0

Four paralleled Schedule 40 PVC conduits will be installed underground to feed a 1000-A, 120/240-volt, 3Ø, 4-wire fused service switch. The calculated load on AØ is 860 A, BØ is 220 A, and CØ is 860 A. The maximum unbalanced load on the neutral is 640 amps. The minimum size of the neutral conductor in each conduit is ___ AWG.

1/0

Scenario 205.2A 400-A, 3Ø main lug panel will be fed with one conduit from a 300-Amp, 3-pole breaker in a 120/208-volt, 3-ph, 4-wire panelboard. The feeder will consist of three 350 kcmil conductors (one for AØ, one for BØ, and one for CØ) plus a grounded conductor. Most of the loads are 120-volt, 1-phase and the neutral load is calculated to be 140 amps.Refer to Scenario 205.2. The smallest neutral that can be run is a ___ AWG.