EET-115 Lab 9 - Grounding & Service Mast

3. The three bus-bar conductors in an outdoor sub-station are supplied by units of post insulators. Each unit consists of a stack of 3-pin insulators fixed one on the top of the other. The voltage across the lowest insulator is 8-45 kV and that across the next is 7-25 kV. Find the bus-bar voltage of the station. [38-8 kV]

The following problems refer to grounding requirements. 1. What is the minimum size copper grounding electrode conductor for a service with three sets of parallel 350 kcmil conductors (three conductors per phase)?

Four No. 12 and four No. 10 conductors are to be installed in a EMT conduit 600 V jacketed. What size EMT conduit is required if a. The conductors are Type T90 Nylon? b. The conductors are Type RW90?

20.a. What's the primary disadvantage of using copper conductors?A. DurabilityB. CostC. AvailabilityD. Weight20.b. The NEC requires that each service-disconnecting means be suitable forA. hazardous locations.B. disconnecting the meter.C. wet conditions.D. the prevailing conditions 20.c. As a general rule, each building or structure is limited to a single service. What's an automatic exceptionto this rule?A. A second service deemed suitable for useB. A second service having the proper markingsC. Emergency systems or fire pumpsD. Higher building occupancy

7.B. The size of a grounding electrode conductor for a service or separately derived system is generally basedon the size of the largestA. ungrounded supply conductor.B. equipment grounding conductor.C. grounded electrode.D. bonding jumper.7.C. Which of the following statements about bonding is true?A. The joint or termination must offer opposition in the circuit for effective electrical connections.B. Effective bonding keeps impedance high if a fault should occur.C. The entire electrical safety circuit is only as good as its strongest bonded link.D. Bonding connections must endure high levels of fault current until overcurrent protective devices can operate.

a.1. A main bonding jumper must only be foundA. within enclosures serving as sub-panels.B. at the grounding electrode.C. on the load side of a GFCI.D. within the enclosure that houses the service disconnecting device.a.2. Which of the following statements about grounding electrode conductors is true?A. They restrict the ground connection.B. They eliminate potential differences between conductive objects and the Earth electrode.C. They facilitate operation of overcurrent protective devices.D. They perform bonding between the Earth and grounded conductors.a.3. Main bonding jumpers are required to be made of _______ or other corrosion-resistant material.A. brassB. aluminumC. copperD. copper-clad aluminum

h.1. In an alternating-current system, the maximum size for a copper grounding electrode conductor isA. 250 kcmil.B. 3/0.C. 500 kcmil.D. 4/0. h.2. The figure shows a fault condition in an ungrounded electrical system. Which of the following will occurbecause of the fault in this system?A. Only the overcurrent protector at Point A will trip open.B. The ground fault will heavily damage the service.C. Nothing will happen until a second ground fault occurs.D. The overcurrent protection will trip, shutting off all the line side power.

1. Which of the following statements about equipment grounding conductors is true?A. Unacceptable equipment grounding conductors include conduit, tubing, and cable armor.B. They must be capable of withstanding the higher level of ground-fault current to perform their safety function.C. They increase voltages above ground potential on conductors and equipment enclosures during normal operation.D. When they're far from their associated circuit conductors, impedance values are kept as low as possible during ground-faultconditions.

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Most residential general lighting circuits are wired with 14-AWG copper conductors and are protected by 15-amp circuit breakers. However, there are many electricians who install 12-AWG copper conductors and protect them with 20-amp circuit breakers. How will you know which conductor size and which circuit breaker size will be used for the general lighting branch circuits in the house you are wiring?

A? Conductor is defined in NEC 240.2 as a conductor, other than a service conductor, having overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are not taps. A. Faulted b. Tap c. Magnetic d. Copper-like

Which of the following is an installation requirement for the grounding electrode conductor in acommunications system?A. It must be run as straight as practicable.B. It must be, at minimum, 4 AWG.C. It must be solid or stranded aluminum.D. It must be isolated and covered.

16. A conductor installed from a bonding/grounding bushing that's used to provide a conducting connectionbetween a raceway and the enclosure that the raceway is connected to is an example of a/anA. grounding electrode conductor.B. bonding jumper.C. equipment grounding conductor.D. impedance device.

Determine the required EMT size for the following combination of conductors:18. Four 8 AWG Type THW and four 12 AWG Type THW:19. Three 350 kcmil and one 250 kcmil Type XHHW conductors and a 4 AWG bare conductor:20. In a nonmetallic-sheathed (Type NM) cable installation, a 10⁄3 with equipmentgrounding conductor is installed in a metal octagonal box to supply two 12⁄2 withequipment grounding conductor branch-circuit cables. What is the minimum sizebox? The box contains internal cable clamps

Airframe Electrical System Question: By what means should aircraft electrical circuits/wires be protected from excessive current? (Source: FAA AC 43.13-1B/2B)

What type of terminal seal is shown here? O Matte 68659 Cable Wire Interface