WorksheetsElectrical - Module 11 - Residential Wiring
Total questions: 56
Worksheet time: 29mins
If the local building code surpasses the requirements of the NEC, what should you follow?
Who provides the single-phase service entrance to a residence?
What do you need to review before calculating the service?
Review the floor plan
According to the NEC, for residential occupancies, you will figure ___ VA per square feet of living space.
What formula do you use to find AREA?
Length x Width
What spaces in a residence do you NOT include when calculating lighting load?
Open porches, garages, or unused/unfinished spaces that are not adaptable to future use
Look at the floor plan:
Calculate the area and the general lighting load required.
65 x 50 x 45 = 146250
146250 x 2 = 292500
65 x 45 = 2925
2925 x 3 = 8775
Which NEC article provides rules regarding the application of demand factors to certain types of loads?
What is a demand factor?
Max amount a VA load expected at any given time compared to the total connected load of the circuit.
What demand factor of each of the fixed appliance loads on a neutral be computed at/
80%
100%
What demand factor does the NEC allow the load calculation for the grounded neutral conductor supplying electric ranges and dryers?
How many VA's are small appliance circuits calculated at?
Names some places in a dwelling where receptacles must have a GFCI protection. (mark all that apply)
Bathrooms, kitchens, garages, & outdoors
crawl spaces & laundry space
When does the GFCI sensor trip?
If the current in the neutral load wire becomes less than the current in the hot load wire.
In what NEC article does it discuss the requirements to ensure systems are properly grounded and bonded?
Why is the neutral conductor allowed to be smaller than the ungrounded conductors in an electrical service?
It only carries the imbalance load
In what NEC section will you find information about equipment grounding and equipment grounding conductors?
Article 240
Article 260
Article 270
Article 250
What are some things that can be used as grounding electrodes? (mark all that apply)
metal underground water pipe, metal in-ground support structures
electrode encased by 2" of concrete, ground ring
plate electrodes
All are listed in Article 250
What cannot be used as an electrode?
Underground gas piping system
marker pen
Lighting rod on top of a barn
Where must rod, pipe, and plate electrodes be buried and what must they be free from?
Below permanent moisture level and free from any nonconductive coatings
What must a grounding electrode conductor be made of?
Where does the NEC require about how electrodes are connected?
All must be listed in NEC - exothermic welding, pressure connectors, clamps, lugs
Where does the main bonding jumper (MBJ) need to be located?
Service disconnect
Why is it important to have a proper MBJ in place?
To ensure the overcurrent device opens during a ground fault
To help increase the changes of an overload.
To create confusion among electricians working
What type of equipment is required to be grounded regardless of the voltage? (mark all that apply)
electrical appliances, IT equipment, washer, dryers, dishwasher
motors, motor controllers, lighting fixtures
Listed FMC can be used as equipment grounding conductor if circuit conductors are protected by overcurrent devices rated at ___ or less.
Name 6 equipment grounding methods. (mark all that apply)
grounding wedge, u-bolt, or clamp
grounding screw, clip, or bushing
What needs to be considered first when planning out the electric service?
Service drop, electric meter and load center
Conductors must be at least (a) above the ground for residential properties, driveways or commercial property that is not subject to truck traffic. This distance can be reduced to (b) when voltage is limited to 300V to ground.
What is the minimum vertical distance for conductors above ground for public streets, alleys, roads, parking areas, etc.?
Where is the main service disconnect or panelboard typically located?
An outside wall - unfinished basement or utility room
If you need to shut off power to the entire residence, where do you do that?
Main electrical panel or circuit breaker box (Panelboard)
In what NEC article does it list requirements for installing a service disconnect?
When do conductors need to be outside of a building with no disconnect needed?
Service conductors supplying a compound
When they are installed under not less than 2" of concrete beneath a building
Service conductors supplying a tent for temp control
What is another name for NM cable?
Residential wiring - Type NM cable:
Bends in type NM must not be less than __ the diameter of the cable.
5
Cables must be secured in place at intervals not exceeding __ feet.
4.5
Cables must be fastened within __ inches from every outlet box.
12
If cable is __ inches away from the nearest edge a nail plate must be used.
1 1/4
Where can Type MC cable be embedded?
plaster, brick, masonry
direct burial
Which type of cable is able to be bent 7 times the cable's diameter?
MC
ODP
PVC
VFD
NM
How often does SE cable have to be fastened when used as service-entrance conductor?
When are conduits or raceways used in residential applications?
Service masts, underground wiring embedded in concrete, unfinished basements, shops, garage areas
What are branch circuits?
Conductors that extend from the panelboard to the outlets
What is a feeder?
What can a feeder be used to supply?
(mark those that apply)
Consists of all conductors between the service equipment
A subpanel from the main panel
How are the minimum requirements for the location of receptacles in dwelling units in terms of spacing?
Every 6'; including any wall space that is more than 2'
When installing conductors to be used for electric heat, the conductors must be sized for (a) of the heaters nameplate rating.
Describe the usual lighting branch circuit that operates at 120V: the (a) (grounded) circuit conductor is therefore connected to the (b) bus in the panelboard, while the (c) (ungrounded) circuit conductor is connected to an (d) .
Why is it sometimes not possible to calculate the exact total load?
Electrician won't always know the wattage used by the homeowner
What is the recommendation regarding residential branch circuits?
The load should not be more than 80% of its capacity
When do ceiling boxes to be marked with maximum weight to be supported?
When rated to support is more than 35 lbs
What is the maximum weight of a ceiling fan is permitted to be supported by an approved outlet box?
Identify the terminal colors:
Equipment grounding conductor
Green
Neutral or grounded conductor
Silver
Ungrounded conductor
Brass
Which slot on a duplex receptable designated the ungrounded (hot) conductor?
What type of cable must be installed between all 3-way and 4-way switches?
A four-way switch needs to be used with (a) in order to control the device from three locations.
What is the chief application of photoelectric switches?
Outdoor lighting / dusk to dawn lights
Where do you find requirements for switch locations in dwelling units in the NEC?
Article 210 of the NEC
Where do you find information on the installation of hot tubs in the NEC?
