Unit 3: Cooking Equipment & Appliance Demand Loads Flashcards
Applying NEC® demand factors and calculation methods to properly size branch circuits and feeders for cooking appliances and other household or commercial equipment.
Fill in the blank:
Continuous-duty motors, more than one hp, with a marked service factor less than 1.15 marked on the motor nameplate shall have the running overload protection sized at _____ of the nameplate rating of the motor, when modification of this initial value is not necessary.
115 percent
Fill in the blank:
When doing feeder and service calculations for dwelling units, the minimum unit load, in VA, shall be not less than _____ per square foot, measured from the outside dimensions of the dwelling unit.
3 VA
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The maximum ampacity rating of an individual branch circuit in a flat conductor cable (Type FCC) assembly shall be _____.
30 amperes
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In dwelling units, GFCI protection is required for all 15-and 20-ampere, 125-volt receptacles located within at least _____ of the outside edge of a bathtub or shower stall.
6 feet
What maximum percent of a metal wireway cross-section may be occupied by splices, taps and conductors at any point?
75 percent
In an underground rigid polyvinyl chloride conduit (PVC) system that consist of 50 feet length between pulling points, what is the maximum number of bends this run may have?
four (4) - 90 degree
Fill in the blank:
Grounding electrodes made of pipe or conduit shall not be smaller than _____ electrical trade size.
3/4 in
True or False:
Liquidtight flexible metallic conduit (LFMC) shall not be used where subject to physical damage.
TRUE
Determine the ampacity of a size 3 AWG THHN copper conductor where given the following related information.
- Two (2) current-carrying conductors are in the raceway.
- The ambient temperature is 35°C.
- The terminations are rated 60°C.
85 amperes
Size 3 AWG THHN ampacity before correcting = 110 amperes
(90oC Column)
110 amperes x .96 (temperature correction) = 105.6 amperes
*NOTE: Size 3 AWG (60oC Column) with an ampacity of 85
amperes should be selected from Table 310.16.
Fill in the blank:
As per a general NEC rule, communications wires and cables shall have a vertical clearance of not less than _____ from all points above roofs which they pass.
8 feet
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Standard trade size 2 in. rigid Schedule 40 polyvinyl chloride conduit (PVC) , shall be supported at least every _____.
5 feet
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Where an ac system operating at less than 1000 volts is grounded at any point at the service, a main bonding jumper shall connect the grounded conductor(s) to _____.
each service disconnecting means enclosure
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In industrial establishments, where sizes 1/0 AWG through 4/0 AWG single conductor cables are installed in ladder type cable tray, the maximum allowable rung spacing for the cable tray shall be _____ .
9 inches
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The NEC mandates the maximum length permitted for a flexible cord supplying a 208-volt, single-phase, room air-conditioner to be _____.
6 feet
In general, which of the following receptacle outlets in a commercial kitchen are required by the NEC to be GFCI protected?
a. All 125-volt, 15- or 20-ampere receptacles only.
b. All 125-volt, 15- or 20-ampere receptacles in wet locations only.
c. All 125-volt through 250-volt, single-phase, receptacles rated 50-amperes
or less.
d. All 125-volt countertop receptacles only.
c. All 125-volt through 250-volt, single-phase, receptacles rated 50-amperes or less.
Fill in the blank:
When installing pendant mounted luminaires, the pendant conductors longer than _____ shall be twisted together where not cabled in a listed assembly.
36 inches
Fill in the blank:
Branch-circuit conductors supplying more than one motor shall have an ampacity of at least _____ of the FLC of the highest rated motor in the group, and 100 percent of the FLC of the other motor(s) in the group.
125 percent
Where required, what is the minimum size wire-type equipment grounding conductor required for a 5 hp, 3-phase, 208-volt motor having 20 ampere rated overload protection and branch-circuit, short-circuit and ground-fault protection rated 30 amperes?
10 AWG
Where a retail clothing store has dimensions of 100 ft. by 75 ft., what is the general lighting demand load, in VA, on the ungrounded (phase) service entrance conductors?
14,250 VA
100 ft. x 75 ft. = 7,500 sq. ft. x 1.9 VA = 14,250 VA
*NOTE: The Note directly below Table 220.42(A) clarifies
that the 125% multiplier for a continuous load as specified in
210.20(A) is already included in the unit load values in the
table when calculating the minimum lighting load for a specified non-dwelling occupancy.
Fill in the blank:
For nonshielded conductors of over 1000 volts, the conductors shall not be bent to a radius of less than _____ times the overall conductor diameter.
eight
Where an ac electrical service is supplied with four (4) parallel sets of size 500 kcmil aluminum ungrounded conductors, what is the minimum size copper grounding electrode conductor required when connected to the concrete encased reinforcing building steel? (Assume the grounding conductor does not extend to other types of electrodes.)
4 AWG
Fill in the blank:
Where an ac transformer arc welder has a 50 ampere rated primary current and a 60 percent duty cycle, the MINIMUM size 60 deg. C rated copper conductors the NEC requires to supply this welder is _____.
8 AWG
Fill in the blank:
When installing wiring for sensitive electronic equipment, the maximum voltage to ground is required to be _____ .
60 volts
In a health care facility, a patient bed location in a critical care area (Category 1) is required to have which of the following?
a. Four single receptacles or two duplex receptacles.
b. Fourteen single receptacles or seven duplex receptacles.
c. Six duplex receptacles or twelve single receptacles.
d. Eight single receptacles or four duplex receptacles.
b. Fourteen single receptacles or seven duplex receptacles.
