Services & DistributionQuestion 92 of 521
A feeder is the main power feeder to a single dwelling and carries the entire load. What allowance does the dwelling feeder provision give for sizing this conductor?
a.It must be sized at 150% of the service rating
b.It may be sized at 83% of the service rating using the dwelling conductor provisions
c.It must always match the utility transformer
d.It cannot be smaller than 250 kcmil
Explanation
Section 310.12(B) permits the main feeder to an individual dwelling (that carries the total load) to be sized using the reduced dwelling-service-conductor values, effectively 83% of the service rating. The other options misstate or invent sizing rules not found in the code.
Law Reference: 2023 NEC §310.12Practice all 521 questions free — no signup required.
Related questions on this topic
- Metal water piping system(s) in or attached to a building must be:
- Ground-fault protection of equipment is generally required for solidly grounded wye services of more than 150 V to ground but not exceeding 1000 V phase-to-phase, where the service disconnect is rated:
- In a typical utility service arrangement, the electric meter (metering equipment) is normally connected:
- As a general rule, each service drop or service lateral is permitted to supply:
- Six current-carrying conductors are installed in a single raceway. The ampacity adjustment factor that must be applied to each conductor is:
- A grounded (neutral) service conductor larger than 6 AWG is permitted to be identified by:
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-10 Electrical Trade Examination · How we review