USCG Exam PracticeElectrical fundamentals — DC/AC, motors, distribution
A shipboard distribution system is described as 'radial.' Which characteristic correctly identifies a radial arrangement and its primary limitation?
- A. It feeds critical buses from two directions; its limitation is higher cost and complexity.
- ✓ It provides one path to each load; a fault or outage upstream de-energizes everything downstream.Correct
- C. It uses an automatic bus transfer to connect the emergency switchboard; its limitation is slow transfer time.
- D. It connects loads in series so each receives a portion of the supply voltage; its limitation is voltage division.
Why B is correct
DOE-HDBK-1011 Vol.4 §15-1 defines a radial system as one that provides a single path to each load and notes that a fault or outage upstream kills everything downstream. Ring/loop and selective layouts feed critical buses from two directions to avoid this vulnerability. Loads in any distribution system are connected in parallel, not series.