303.3-303 SB

A primary reason for equipment grounding is to provide an effective ground fault current path. The impedance of the grounding path is directly related to the amount of time a fault exists before the OCPD operates. When impedance is higher, the fault lasts ___ time.

A longer period of (time)

The furseweld exothermic welding process is ignited with a spark gun that starts a reaction in the weld powder. The weld powder is reduced to a molten alloy of ___.

Copper

Furseweld exothermic welding connections are made inside a semi-permanent graphite mold using the high temp reaction of powdered ___.

Copper Oxide and Aluminum

Which of the following is not a required characteristic of a grounding path according to Section 250.4(A)(5)?

It must be equipped with ground fault monitors.

The OSHA regulations set the minimum lighting level for different areas on construction sites. These levels are dependent upon the task being performed in the work area. For example, ___ foot candles are required in an area used for offices than the number that would be required for storage.

More

When light strings are utilized on a construction site, empty sockets or sockets with shattered lamps should be replaced ___ after being reported.

More

NEC section 110.9 requires that electrical equipment ___.

intended to interrupt fault current be so rated

The purpose of maintaining low impedance fault current return path is to ___.

quickly open an OCPD

To provide convenience receptacles and lighting for temporary construction sites, a minimum of ___ circuits are required.

2

During the period of construction, ___ foot candles are required in electrical equipment rooms.

10

Temporary electric splices are to be insulated and inaccessible. When these splices are more than ___ feet above the floor, they are considered to be inaccessible.

8

NEC section 250.8 requires equipment grounding conductor connections to be made by which of the following methods?

Any of these; Listed clamps, exothermic welding, listed pressure connectors)

___ can be used to connect grounding conductors and bonding jumpers.

Any of these; Listed clamps, exothermic welding, listed pressure connectors)

All equipment grounding conductors and grounding buses in service panels must be ___.

Bonded together

The earth is not acceptable as the sole equipment grounding conductor or effective ground fault current path due to ___.

High impedance of the earth

Refer to figure 301.02 shown above. Flex is used between switch and the motor. A "hot", a neutral and a grounding conductor were installed in the EMT and the flex. The insulation on the hot has been damaged and the copper is touching the motor terminal housing. The fault current path to trip the circuit breaker will travel through ___.

I & II only(EMT and MBJ)

Shown in figure 303.01 is a 277/480 volt, three phase, 4 wire transformer supplying a panel. If a ground fault occurs when the ungrounded conductor touches EMT #1, the fault current will travel through the ___ to get back through the transformer windings and finally to the OCPD to cause it to open.

I, II, III, & IV(separate EGC, EMT, SBJ, secondary neutral conductor)

When a ground fault occurs in a 208 volt, single phase branch circuit, the fault current must travel through the ___ to get back to through the OCPD to cause it to open. The 208 volt circuit originates in a 120/208 volt circuit originates in a 120/208 volt, three phase 4 wire service panelboard.

I,II, & III(EGC, MBJ, UGC)

Shown in figure 303.02 is a 277/480volt, 3phase, 4wire transformer supplying a panel. If a ground fault occurs when the ungrounded conductor touches EMT #1, the fault current will travel through the ___ to get back through the transformer windings and finally to the OCPD to cause it to open.

I,II, & III(EMT,SBJ, secondary neutral conductor)

Shown in figure 303.03 is a 277/490 volt, three phase, 4 wire transformer supplying a panel. If a ground fault occurs when one of the ungrounded 490 volt, single phase circuit conductors touches EMT #1, the fault current will travel through the ___ to get back through the transformer windings and finally to the OCPD to cause it to open

I,II,III, & IV(separate EGC, EMT ,SBJ, & secondary neutral conductor.

A 277/480, 3phase, 4wire, main breaker panel board is installed as the main service, The MBJ for this panel was misplaced and never installed. A 277 volt circuit is run in EMT from the panel to some fluorescent lay-in luminaires. if the hot conductor is nicked in the terminal box in the luminaire and touches the luminaire's metal enclosure, ____.

The grid will be hot and the luminaire says ON because the breaker doesn't recognize high fault current and therefore won't trip

A 120 volt circuit is installed in EMT without a separate EGC. The circuit originates in a 120/208 volt. 3phase,4wire panelboard. To cause the OCPD to operate, when a ground fault occurs in the branch circuit, the fault current must travel through the system (or main) bonding jumper.

True

Solder connections are not among the methods permitted by NEC section 250.8 for connecting the main bonding jumper because solder has a low melting temp and fault currents can generate enough heat to melt the solder and destroy the connection.

True

The bonding jumper installed between a piece of electrical utilization equipment and a grounded metal element, such as a water pipe, minimizes shock hazard becasue it elimates the potential difference between the electrical equipment and the grounded metal element( or water pipe)

True

Where construction work is in progress, OSHA requires areas, aisles, stairs, ramps, runways, corridors, offices, shops, and storage areas to be lighted.

True

Free standing temporary light stands ___ permitted to be used on construction sites.

are