Electrical
Minimum Clearance Requirement: over all walking areas, sidewalks, decks, roof surfaces and patios used by pedestrians only, measured from final grade or other accessible surfaces
10 feet at the electrical service entrance, at the lowest point of the drip loop
The point of attachment of the overhead service conductors to a building or other structure should be not less than ______ above finished grade.
10 ft
Minimum Clearance Requirement: over residential properties, yards, driveways, and any other parking areas
12 ft
Typical electrical service to a house is
120/240V split system provided by a pole-mounted distribution transformer located at the service drop
In alternating current wiring, there are about
120V in the "hot" or the energized wire.
Most 120V circuits are wired to deliver
15 - 20 amps of current
Minimum Clearance Requirement: over commercial parking areas
18 ft
Minimum Clearance Requirement: over public streets, roads, alleys, and parking areas with truck traffic
18 ft
Minimum Clearance Requirement: termination of through-the-roof raceway or approved support above the overhanging portion of the roof that is less than 4 feet measured horizontally
18 inches
Service entrance cable needs to be buried at a minimum depth of ____ under landscape and _____ under hardscape (like driveways)
18 inches 24 inches
UF cable, rated for direct burial, must be buried in a depth of:
18-24 inches
Round meter bases
1920-1950 rated for only 60 amps
Square meter readers
1950 - 1970 still used in smaller housing units like apts rated for 100 - 125 amps
Electrical circuit requires a minimum of ____ wires.
2
Most residential construction requires _____ grounding electrodes which need to be at least _____ __ apart.
2 6 ft
Minimum Clearance Requirement: over swimming pools
22 feet and 6 inches above and 10 feet horizontally
Minimum Clearance Requirement: over roof surfaces where voltage is 300 or less and the roof area is guarded or isolated
3 ft
Minimum Clearance Requirement: over roofs surfaces having a slope of 4:12 or greater
3 ft
Minimum Clearance Requirement: from sides of doors, porches, decks, stairs, ladders, fire escapes and balconies, and from the sides and bottom of windows that open
3 ft from bottom, sides, and front
Grounding electrodes of pipe and conduit must be at least
3/4 inch
If rod or pipe electrodes cannot be driven in vertical, what is an alternate way?
45 degree angle
Rods made of stainless steel and copper, or zinc-coated steel, shall be at least
5/8 inch in diameter
Currents of ____ to _____ __________ can be fatal
50 to 100 milliamperes
All rod electrodes should be driven ______ into the ground
8 feet
Minimum Clearance Requirement: above roof surfaces having a slope of less than 4:12 and not subject to pedestrian traffic
8 feet, maintained for a distance of at least 3 feet in all directions from the edge of the roof
Branch Circuit
A branch circuit are the conductors between the final overcurrent device protecting the circuit and the outlet(s).
Cabinet
A cabinet is a mounted enclosure with a swinging door.
Dead Front
A dead front is without live parts that are exposed to someone on the operating side of the equipment.
Disconnecting means
A device by which the conductors of a circuit can be disconnected from their source of supply.
Circuit breaker
A device designed to open and close a circuit by non-automatic means and to open the circuit automatically when there's an overcurrent.
What is a jumper?
A large gauge conductor that "jumps" over the water meter and is securely attached to the metal water pipe on each side
Current
A measurement of the rate of flow of electricity through a conductor. Current is measured in amps.
Panelboard
A panelboard is a single panel, including buses and automatic overcurrent devices, and equipped with or without switches for the controlling of light, heat or power circuits, and is mounted in a cabinet, and is accessible only from the front.
Receptacle
A receptacle is a contact device installed at the outlet for the connection of an attachment plug.
Device
A unit of an electrical system, other than a conductor, that is intended to carry or control but not utilize electricity. Examples of devices are switches and thermostats.
AWG
American wire gauge (AWG) is a standardized wire gauge system used since 1857 predominantly in North America for the diameters of round, solid, nonferrous, electrically conducting wire.
Current is measured in ______, which travels from a ______ ________, through the device is operates, called the _______, then back to the source to complete its _________.
Amps power source load circuit
Outlet
An outlet is a point on the wiring system where current is taken to supply equipment.
Receptacle Outlet
An outlet where one or more receptacles are installed.
Overcurrent Protection Device
An overcurrent protection device set to open a circuit when the current exceeds a set value.
AFCI
Arc Fault Circuit Interrupter a device that provides protection from the effects of arc-faults by recognizing arcing and deenergizing the circuit when an arc-fault is detected.
Bonded
Connected to establish electrical continuity and conductivity.
Rectangular meter reader
Current minimum on single family homes 200 amps
Apms =
E/R
GFCI
Ground-Fault Circuit-Interrupter GFCI is a device that protects a person by deenergizing a circuit when a current to ground exceeds the value for the device.
kcmil
In North America, conductors larger than 4/0 AWG are generally identified by the area in thousands of circular mils (kcmil), where 1 kcmil = 0.5067 mm².
Line
Line refers to the incoming power. The line side of the equipment will be where the source of the power is terminated.
Load
Load refers to the outgoing power.
Watts measure power
Power is measured in watts, and you can compute wattage by multiplying amperage and volts.
Romex
Romex is a trade name for a type of NM cable. Romex is the most commonly used wiring in homes.
SE and SEU cable
SE Cable stands for service entrance cable, which is not commonly used for service cable any longer, but is used for branch circuit and feeder wiring in homes. SEU is an SE cable and the U stands for underground. SEU cable is identified for underground use.
what does SEC stand for?
Service entrance cable
Service
The conductors and equipment for delivering energy from the service utility to the wiring system of the home.
Feeder
The feeder is a circuit of conductors between the service equipment and the final overcurrent device. Circuits feeding subpanels are called feeders.
Ampacity
The maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Volts measure pressure
The pressure under which electricity moves is measured in volts. Electricity arrives at household circuits at a "pressure" of 120 or 240 volts.
Amps measure current
The volume of the current (the number of electrons flowing past a given point per second) is measured in amperes, or Amps.
T/F The service entrance cable is not rated for direct burial.
True
Appliance
Utilization equipment that performs a function such as clothes washing or air conditioning.
Electrical power is measured in
Watts
Common Ohms Laws
Watts equals Volts times Amps, or W = E x I. Another would be Amps = Watts divided by Volts, or I = W / E.
An arc flash occurs when
a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to neutral, or ground.
Service-entrance cable is
a line of service conductors located between the terminals of the service equipment and a point usually outside the building where they are joined by a tap or splice to the service drop or overhead service conductors.
In electrical power situation, a bushing is
an insulated device that allows an electrical conductor to pass through something else that may be conductive
Ufer grounds is also known as
concrete encased electrode
SEC (service entrance cable)
conductor assembly that connects from the service supply, through the meter socket, and on to the primary disconnecting means
a jumping or bonding conduct
conductor that is used to ensure there is electrical conductivity between metal parts that are required to be electrically connected
SECs are made of:
copper or aluminum
Grounding
direct connection to the earth to aid in removing damaging transient over voltage due to lighting.
Most common method of connection grounding system to ground
driven rod
240V circuit is used for home's
electrical appliances that require substantial power like furnace, water heater, A/C, washer and dryer, oven
Bonding
ensure electrical continuity of the fault current path, provide the capacity and the ability to conduct safely any fault current likely to be imposed, and to aid in the operation of the over-current protection device.
Current =
flow rate = Apms = I
The masthead is sometimes called: Located where?
gooseneck at top of the mast itself
Power
is the amount of work that the electrical flow can do. This is expressed as watts or kilowatts (1,000 watts).
Current
is the flow of electrons driven by electromotive force through a given resistance. This is expressed as amps.
Electromotive force
is what drives electrons along the conductor, and is expressed as voltage or volts.
copper inherently has ______ resistance to the flow of electrons than aluminum does.
less
120V circuit is used for home's
lighter electrical loads like lighting, electronics, portable appliances
Resistance
limits the conductor's ability to allow the flow of electrons, just as friction causes losses in any pipe or duct work. This is expressed in Ohms.
The inspector should report any ______ _______ or ______ in the masthead and its ______.
loose fittings or cracks clamp
Electric meter is there to:
measure the amount of power used on the property
Return conductor, known as _______, is at __ volts because it is grounded at the _______ _______.
neutral 0 electrical panel
pipe or conduit made of steel should have an
outer surface that is galvanised or otherwise metal coated to resist corrosion
Service Drop
overhead service conductors located between the utility electric supply system and the service point.
Resistance =
pipe size = Ohms = R
Service point
point of connection between the facilities of the service utility and the wiring at the house.
Voltage =
pressure = volts = E
The "SE" in SE cable stands for:
service entrance
The service cables are connected to the _________ _________ cables by ________ ___________, which are then covered in an __________ ___________.
service entrance crimped connectors insulates sleeve
If pipe or conduit is used as a grounding electrode, it must also be no less
than 8 feet in length
Electrical current is actually
the movement of electrons flowing along a conductor in much the same way as water flows through a pipe
Common wires used electric power distribution in homes can be identified by a wire size followed by
the number of wires used in the cable assembly.
Electric meter is normally part of:
the service entrance equipment
Two purposes of the masthead are?
to act as a rain cap to stop moisture from entering the conduit and to provide the bushings to prevent the individual conductors from being damaged by rubbing against the metal components
Service drop is made up of
two 120V lines and one neutral line
Service drop provides the home
two 120V lines of opposite phase
Cable rated for direct burial
type - UF
Power or watts (W) is = to
voltage (V) multiplied by the current (I)
Service Lateral
when the electrical supply is fed underground