Electrical

Question 1

Are flexible cords (marked SO, SJ, SJO, etc…) acceptable for fixed installation? (ES)

Answer 1

Ref: 46 CFR 183.10-20(2)

No

Question 2

When is overcurrent protection required on generators?

Answer 2

Ref: 46 CFR 183.320(f)

Each generator must be protected by an over current device set value not exceeding 115 percent of the generator full load rating.

Question 3

What is acceptable as emergency lighting on a “T-boat”?

Answer 3

Ref: 46 CFR 183.320

Lighting fitted along the line of escape to the main deck from all passenger and crew accommodation spaces located below the main deck. automatically actuate upon failure of the main lighting system or individual battery powered lights that:
Are automatically actuated upon loss of normal power; Are not readily portable; Are connected to an automatic battery charger; and Have sufficient capacity for a minimum of 2 hours of continuous operation.

Question 4

What is the prime concern when checking a battery hooked to a charger?

Answer 4

Ref: 46 CFR 183.350(a)

There must be natural or induced ventilation sufficient to dissipate the gases generated.

Question 5

What size fuse would you recommend for an electrical conductor of non-standard size?

Answer 5

Ref: 46 CFR 183.380(d)

If the allowable current carrying capacity does not correspond to a standard device size, the next larger over current device may be used provided it does not exceed 150 percent of the conductor current carrying capacity.

Question 6

Switchboards located in spaces accessible to passengers must have?

Answer 6

Ref: 46 CFR 183.330(d)

Distribution panels and switchboards that are accessible from the rear must be constructed to prevent a person from accidentally contacting energized parts.

Question 7

When is over-current protection required on motors? How do you determine the amount of protection?

Answer 7

Ref: 46 CFR 183.376(h)

Over current devices capable of carrying the starting current of the motor must be installed to protect motors, motor conductors, and control apparatus against:

(1) Over current due to short circuits or ground faults; and
(2) Overload due to motor running over current

Question 8

What electrical equipment is required to be protected under the “drip proof” standard?

Answer 8

Ref: 46 CFR 183.210(a)

A machinery space; A location normally exposed to splashing, water wash down, or other wet conditions within a galley, a laundry, or a public washroom or toilet room that has a bath or shower; or Another space with a similar moisture level.

Question 9

How would you inspect an electrical breaker panel?

Answer 9

Ref: 46 CFR 183.330

Ensure panel is of marine grade, properly labeled with directory card, no open slots, securing latch works, grounded, each breaker rating labeled and properly sized.

Question 10

If an electrical outage occurs, what provision must be on board for lighting?

Answer 10

Ref: 46 CFR 183.432(a)

Emergency lighting

Question 11

What meter is required to be mounted for each AC generator?

Answer 11

Ref: 46 CFR 183.320(c)

In addition, a frequency meter

Question 12

What information needs to be listed on the housing on all motors on “T-Boats”?

Answer 12

Ref: NFPA 70, Article 430

Maker’s name, rated volts, full amperes, full load speed, rated temp and rated horse power.

Question 13

What is the smallest wiring normally allowed in electrical circuits?

Answer 13

Ref: 46 CFR 183.340(c)

Conductors in power and lighting circuits must be No. 14 American Wire Gauge (AWG) or larger. Conductors in control and indicator circuits must be No. 22 AWG or larger.

Question 14

What electrical loads must be capable of being energized from two sources of power?

Answer 14

Ref: 46 CFR 183.310(a)

Vital systems, interior lights, Nav lights, Comms

Question 15

Where are emergency lights required?

Answer 15

Ref: 46 CFR 183.432(a)

along the line of escape to the main deck from all passenger and crew accommodation spaces located below the main deck.