USCG Exam PracticeElectrical fundamentals — DC/AC, motors, distribution
A shipboard distribution system is described as 'radial.' Which characteristic best defines this arrangement?
- A. Critical buses are fed from two directions so a single failure does not cause a blackout
- ✓ There is one path from the source to each load, so an upstream fault or outage de-energizes everything downstreamCorrect
- C. An emergency switchboard with automatic bus transfer feeds all loads simultaneously
- D. Loads are connected in a loop so fault current can be isolated without interrupting service
Why B is correct
A radial system provides one path to each load. It is simple and inexpensive but a fault or outage upstream de-energizes all downstream loads. Ring/loop and selective layouts feed critical buses from two directions to avoid this vulnerability. (DOE-HDBK-1011 Vol.4 §15-1)