Test 5

Ace your homework & exams now with Quizwiz!

Where conductors do not enter or leave the enclosure through the wall opposite its terminal, the minimum wire bending space at terminals for a single 6 AWG conductor will be

1 1/2 inches (NEC - 312.6(B))

Where an ac system operating at_ or less is grounded at any point, the grounded conductor s) shall be routed with the ungrounded conductors to each service disconnecting means and shall be connected to each disconnecting means grounded conductors) terminal or bus.

1,000 volts (NEC - 250.24(D) grounded conductor brought to service equipment ... 1000 volts or less)

A permanent swimming pool holds water at a depth of how many inches or greater?

42 inches (NEC - 680.2 " permanently installed swimming pools" ... holding water in a depth than 42 in.)

If the disconnecting means (including a switch or circuit breaker) is not within sight of the appliance of a permanently connected appliance rated over 300 VA, it shall be capable of being locked in the

Open position (NEC - 422.31(B), 110.25)

Each sign and outline lighting system, feeder conductors), or branch circuits) supplying a sign, outline lighting system, shall be controlled by a disconnecting means, located at which of the following?

within sight of the sign, within sight of the controller (NEC - 600.6(A))

A heating element for a clothes dryer is rated at 5,000 watts at 240 volts. A homeowner doesn't have 240-volts available and connects it to 120 volts. What is the operating wattage of the element?

1.250 (Ohm's Law: R = (ExE)/P = 57600/5000 = 11.52 Ohms, so new power P = (ExE)/R = (120 x 120)/11.52 = 1,250 watts)

A dwelling unit kitchen contains a counter-mounted cooking unit rated at 8 kW, and two wall-mounted ovens rated 8 kW and 7 kW, all supplied from a single branch circuit. What is the total demand factor of the cooking units?

12.4 kW (Table 220.55 + Note 4 + Note 1. 8+8+7 = 23-12 = 11 * 5% = 0.55. Therefore, 1.55 x 8,000 = 12,400VA)

***** Service Load Calculations (Optional Method) What would be the net calculated load after applying the demand using Optional Method per Table 220.84(B), given that a multi-family dwelling has 6 units with a load of 10 kVA per unit?

26,400 VA (NEC - Net calculated load using Optional Calculation per Table 220.84(B), lists a 44% demand factor for six units. See calculation below. Step_1: 6 dwelling units' x 10,000 VA per unit = 60,000 VA Step_2: Apply the demand factor of 44% per Table 220.84(B), 60,000 VA x 0.44 = 26,400 VA Note: See Annex D Example D4(b) Optional Calculation for Multifamily Dwelling)

Equipment such as room air conditioners shall be considered appliances, and the provisions of the NEC Article 422 shall apply. Therefore, what would be the minimum required ampacity for the conductors serving the branch circuit of a single motor air conditioning unit with a nameplate rating of 21.2 amperes?

26.5 amperes (NEC - 440.32 ...shall have an ampacity not less than 125 percent of either the motor compressor rated load current or the branch circuit selection current, whichever is greater. Therefore, see math below. Calculate; Conductor Ampacity = Motor Nameplate Rating x 125% = 21.2 amperes x 1.25 = 26.5 amperes.)

Submersible pumps and other submersible equipment in fountains shall NOT operate over how many volts between conductors?

300 (NEC - 680.51(B))

NEC Table 110.26(A)(1) lists the required working spaces for exposed live parts or from the enclosure or opening if the live parts are enclosed. Therefore, if the installation is 151-600 volts with exposed live parts on both sides of the working space, what is the requirement?

4 feet (NEC - Table 110.26(A)(1) Working Spaces)

*****Branch-Circuit Lighting Load Calculations (220.5(C), 220.41) Given, a single family dwelling has 3,275 square feet of habitable area, and the service is 120/240-volts. Therefore, how many 15 ampere general purpose branch circuits required for the general lighting and receptacle loads?

6 (NEC - 220.5(C), 220.41, Annex D Example DI(a). See steps below: Step_1: Calculate, 3,275 sq-ft x 3 VA/sq-ft = 9,825 VA Step - 2: Use Ohm's Law I = P/E = 9,825 VA / 120 V = 81.875 A Step - 3: Calculate, 81.875 A / 15 A per circuit = 5.458 circuits Step - 4: Round up the 5.458 circuits to 6 circuits. Note: In addition to the above, at least four (4) more 20-amp branch circuits are required (two for small appliances, one for bathrooms and one for laundry) per NEC 220.16. Annex D Example DI(a) a 1,500 sq-ft dwelling load calculation: General Lighting Load: 4500 VA / 120 V = 38 A This requires THREE 15-A, 2-wire or TWO 20-A, 2-wire circuits. Small-Appliance Load: Two 2-wire, 20-A circuits. Per 210.11(C)(l) Laundry Load: One 2-wire, 20-A circuit. Per 210.11(C)(2) Bathroom Branch Circuit: One 2-wire, 20-A circuit (no additional load calculation is required for this circuit). Per 210.11(C)(3).)

For a stationary motor rated at 1 hp, 240 volts, the controller shall be permitted to be a general use snap switch where the motor full load current rating (FLC) is not more than WHAT PERCENTAGE of the ampere rating of the switch?

80 percent (NEC - 430.83(C)(2) ... 80 percent of the ampere rating of the switch)

Raceways shall be used only as a means of support for other raceways, cables, or nonelectrical equipment under any of the following conditions?

Where the raceway contains power supply conductors for electrically controlled equipment and is used to support Class 2 circuit conductors or cables that are solely for the purpose of connection to the equipment control circuits. (NEC - 300.11(C)(2))

Where portions of a raceway or cable are subjected to different temperatures, the raceway or sleeve shall _ to prevent the circulation of warm air to a colder section of the raceway or sleeve.

be filled with an approved material (NEC - 300.7(A) ...the raceway or sleeve is sealed to prevent the circulation...)

Which device functions as protection of personnel by de-energizing a circuit (or portion thereof) within an established period of time, when a current to ground exceeds the values established for a Class A device?

ground fault circuit interrupter. (NEC - art 100 .. GFCI)

Generators with greater than 15 kW rating shall be provided with a remote emergency stop switch to shut down the prime mover. The remote emergency stop switch shall be located ____?

outside the equipment room or generator enclosure (NEC - 445.19(B) ... outside of the generator equipment room)

The equipotential bonding required for pools shall be installed to reduce

voltage gradients. (NEC - 680.26(A))


Related study sets

100 Citizenship/Naturalization Test Questions

View Set

bus man - the operations management function

View Set

Hypertensive Disorders of Pregnancy

View Set

MASTER- Salesforce Data Architecture and Management Designer

View Set

Chapter 7 - Commerce and Culture

View Set