You are going to install the three-section 1000-amp, 120/208-volt, 3-ph, 4-wire service switchboard as shown in Figure 307.32. Each service conduit contains 4 each 300 kcmil THHN/THWN aluminum conductors. From a 3-pole 350-amp breaker in Section 3, a branch circuit is run in parallel conduits exiting the bottom. Each of these conduits contains 3 each 4/0 AWG aluminum conductors for the 3-phase load. The minimum size of each of the two copper conductors, connected between the ground bar and each branch circuit pipe, is ___ AWG.
Select one:
a.4
b.3
c.6
d.2
e.1/0
