Originally Posted by Bkessler
Answer is B,90 table 430.22e
#3) What size conductor is the smallest size conductor to be run in parallel?
d) 250 mcm
e) 500 mcm
310.4 Conductors in Parallel.
Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG
and larger, comprising each phase, polarity, neutral, or grounded circuit conductor shall be permitted to be connected in parallel (electrically joined at both ends).
Exception No. 1: Conductors in sizes smaller than 1/0 AWG
shall be permitted to be run in parallel to supply control power to indicating instruments, contactors, relays, solenoids, and similar control devices, or for frequencies of 360 Hz and higher, provided all of the following apply:
(a) They are contained within the same raceway or cable.
(b) The ampacity of each individual conductor is sufficient to carry the entire load current shared by the parallel conductors.
(c) The overcurrent protection is such that the ampacity of each individual conductor will not be exceeded if one or more of the parallel conductors become inadvertently disconnected.
Exception No. 2: Under engineering supervision, grounded neutral conductors in sizes 2 AWG
and larger shall be permitted to be run in parallel for existing installations.
FPN to Exception No. 2: Exception No. 2 can be used to alleviate overheating of neutral conductors in existing installations due to high content of triplen harmonic currents.
(E) Equipment Grounding Conductors. Where parallel equipment grounding conductors are used, they shall be sized in accordance with 250.122. Sectioned equipment grounding conductors smaller than 1/0 AWG
shall be permitted in multiconductor cables in accordance with 310.13, provided the combined circular mil area in each cable complies with 250.122.
620.12 Minimum Size of Conductors.
The minimum size of conductors, other than conductors that form an integral part of control equipment, shall be in accordance with 620.12(A) and (B).
(A) Traveling Cables.
(1) Lighting Circuits. For lighting circuits, 14 AWG copper, 20 AWG
copper or larger conductors shall be permitted in parallel, provided the ampacity is equivalent to at least that of 14 AWG copper.
If the test is tricky, the answer can be:
1) 1/0 AWG
2) < 1/0 AWG
3) 2 AWG
4) 20 AWG
/s/ Jim Williams