SAMS Vessel Electrical Systems 4

Question 1

A vessel has a 30-amp, 120V shore power system. What is the maximum continuous load that should be placed on this system according to NEC/ABYC principles?

Accepted Answer

24 amps

Answer

30 amps

Answer

20 amps

Answer

15 amps

Question 2

When a marine surveyor observes that a vessel's alternator output wire lacks an overcurrent device near the alternator, the primary risk is:

Accepted Answer

Fire from a short circuit in the unprotected alternator output lead

Answer

Reduced battery charging efficiency

Answer

Overcharging the battery bank

Answer

Alternator damage from excessive voltage

Question 3

Sacrificial zinc anodes on a vessel are part of the:

Accepted Answer

Cathodic protection system

Answer

Bonding system

Answer

Impressed current system

Answer

Lightning protection system

Question 4

A surveyor finds that a vessel's bilge blower does not run before engine start. Per USCG regulations, gasoline-powered vessels with enclosed engine spaces must run the blower for a minimum of:

Accepted Answer

4 minutes

Answer

2 minutes

Answer

5 minutes

Answer

10 minutes

Question 5

During inspection of a vessel's electrical panel, a surveyor notes that circuit breakers are used in both the ungrounded (positive) and grounded (negative) conductors. For DC systems, ABYC E-11 requires overcurrent protection in:

Accepted Answer

Only the ungrounded (positive) conductor

Answer

Both positive and negative conductors on all circuits

Answer

Only circuits exceeding 50 amps

Answer

Both conductors only when shore power is connected

Question 6

A vessel's electrical diagram shows a 'common ground buss' connecting all DC negative returns. The best practice for this installation is that the common ground buss should:

Accepted Answer

Connect to the battery negative terminal through a single large conductor, not to the bonding system

Answer

Be connected directly to the engine block for the shortest ground path

Answer

Be grounded to the seacock for corrosion protection

Answer

Connect to shore power neutral when docked

Question 7

When surveying a vessel equipped with a diesel engine, the surveyor notes the fuel system lacks a bonding connection to the vessel's bonding system. For diesel vessels, bonding of fuel tanks:

Accepted Answer

Is not required by ABYC because diesel fuel's flash point eliminates ignition risk from static

Answer

Is mandatory to prevent static discharge ignition

Answer

Is required by USCG for all vessels over 26 feet

Answer

Is only required when the vessel operates in salt water