1
Aluminum wire expands and contracts to a greater degree than does copper wire for an equal load. This is referred to as elongation
what is F
nonmetallic sheathed cable may be run exposed or concealed or concealed in dry locations T/F
what is true
To make voltage drop and conductor sizing calculations for a 3-phase system, substitute the factor of 2.732 in the place of the factor 2 in the voltage drop formula T/F
what is F
10,15,20 amperes rated branch circuits serve more than one outlet in usual dwelling T/F
what is T
Exception 1 to 312.5(c) requires that each cable is fastened within 10 inches measured along the sheath, of the outer end of the raceway
what is F
Voltage drop in a residence can be observed when motors run how?
what is slower and hotter
the surface of aluminum does what as soon as it is exposed to air
what is oxidizes
A simple formula for calculating voltage drop on single phase systems considers what
what is resistance, amp rating and length of the wire
terminations for all electrical connections to devices and equipment are required to be tightened to the torque as required by who
what is manufacturer
Nonmetallic sheathed cables are usually secured to a panelboard, box, or cabinet with what
what is clamps or connectors
the ampacity values in the tables are valid where there are no more than how many current carrying conductors in a raceway or cable and where the temperature does not exceed 86 F
what is Three (3)
Cables may feed surface mounted enclosures. where cable is used, each cable shall be secured to what
What is cabinet, cutout box, or meter socket enclosure
the current-carrying capacity of copper wire for a given size, insulation , and temperature OF 30 C is rated how compared to aluminum
what is more that of aluminum
the ampere rating of the branch circuit overcurrent protective device determines the rating of what
what is the branch circuit
ampacity value depends on the conductors cross-sectional area, whether the conductor is copper, copper-clad, aluminum and what?
what is insulation
even though conductors are sometimes rated higher, NEC 240.4 D spells out the maximum overcurrent protection for small branch circuit conductors. that section limits 14 AWG copper to what
what is 15 amp overcurrent device
Aluminum conductors have a higher resistance compared to copper conductors of same size. when considering what a conductors resistance is a key ingredient.
what is voltage drop
what is the maximum overcurrent protection for 12 AWG copper conductors is what
what is 20 amp
For branch circuits the recommended maximum voltage drop is what
what is 3%
for feeders the recommended maximum voltage drop is what
what is 3%
when both branch circuit and feeders are involved, the total voltage drop should not exceed what %
what is 5%
connectors not marked AL or AL/CU are for use with what kind of conductor
what is copper conductor
If the ambient temperature exceeds what, the ampacity values must also be corrected
what is 86F (30 C)
Circuits must be protected against overcurrent by what or circuit brakers rated not more than the ampacity of the conductors
what are fuses
312.5 C exceptions allows cables with nonmetallic sheaths to enter the top of a surface mounted enclosure through one or more nonflexible raceways not less than how many inches and no more than how many ft under certain conditions
what is 3 inches and 10 feet