Kansas Residential Electrician Exam (ICC KGX, 2017 NEC)

The main bonding jumper is the connection between the grounded circuit conductor and the equipment grounding conductor at the service, while a system bonding jumper serves a similar function at a separately derived system.

Ungrounded line one is black and line two is red, while the grounded neutral conductor is white or gray.

The single-phase three-wire system uses black and red ungrounded conductors with a white/gray neutral, while the delta high-leg system has a B phase that must be colored orange or tagged (caution: 208 volts orange to white).

Per Article 90.2(B), the Code does not cover ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles.

A continuous load is one where the maximum current is expected to continue for 3 hours or more and is taken at 125% in feeder sizing, while noncontinuous load is counted at 100%.

Both use noncontinuous load plus 125% of continuous load, but one sizes the conductor ampacity and the other sizes the overcurrent protective device.

Per NEC 240.2 a tap conductor is a conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply exceeding the value permitted for similar conductors protected per 240.4.

Class 1 circuits are not permitted to exceed 600 volts, while Article 411 low-voltage lighting systems operate at no more than 30 volts ac or 60 volts dc.

Per the Article 760 definition, fire alarm circuits are classified as either non-power-limited or power-limited, and this classification determines the applicable installation requirements.

For spans of 1000 volts or less, open individual conductors must be not smaller than 10 AWG copper for spans up to 50 ft and not smaller than 8 AWG copper for longer spans unless supported by a messenger wire.

For a 3-wire, single-phase dwelling unit service, conductors are permitted to have an ampacity of 83% of the service rating, allowing 2/0 AWG THW copper for a 200-ampere service instead of the 3/0 AWG otherwise required.

Derating factors may be applied to the higher 90°C ampacity, but the final derated ampacity cannot exceed the terminal temperature rating (for 1/0 AWG copper, the 75°C rating of 150 amps).

Surface-type enclosures in damp or wet locations require at least 1/4 in. airspace from the wall, but the exception permits nonmetallic enclosures to be installed without the airspace on concrete, masonry, tile, or similar surfaces.

In a series circuit the total current equals the current in any other part (IT = I1 = I2 = I3) and resistances add, while equal resistors in parallel combine to a lower resistance (e.g., two 30 Ω in parallel = 15 Ω).