Apprentice Lineman General Knowledge

__________ percent of the resistance surrounding an electrode is within a radius of 6' to 10' from an electrode.

90

What is the formula for voltage in a parallel circuit?

Et = E₁ = E₂ = E₃ = E₄...

What NECA district covers outside work exclusively?

Tenth District

The purpose of oil in a transformer is:

cool and insulate the coils

In a circuit the current is __________ proportional to the voltage and __________ proportional to the resistance.

directly, inversely

The opposition to current flow through a material is called?

resistance

Which winding on a constant current transformer is moveable, primary or secondary?

secondary

A circuit having only one current path is called a __________ circuit?

series

Current transformers are connected in __________ with the load.

series

One mill is equal to __________ of an inch?

1/1000

How deep should a gain be cut?

1/2"

Material and debris shall not be placed within how many inches of an open trench in which a man can work?

18"

What is the speed of light?

186,000 miles per second

What year was the IBEW formed, and who was its President?

1890, Henry Miller

What current are constant current transformers usually fixed at?

6.6 amps

How many hertz are used in AC in the United States?

60 Hz

Aluminum has what conductivity, tensile strength, and weight of copper?

60%, 45%, 33%

What ratio does an auto transformer usually have?

2:1

What is the maximum depth of an excavation without the use of shoring?

4'

What keeps a transformer from acting as a short circuit?

Counter voltage (aka: back voltage, CEMF)

What are two types of instrument transformers?

Current & Potential

What materials do electrons travel freely through?

conductors

When the overload circuit breakers are open, the:

primary is still energized

Does the red warning light on a CSP transformer mean that an overcurrent exists now?

No

What is the equivalent resistance in a magnetic circuit?

reluctance

What is the formula for number of windings to voltage?

voltage primary/voltage secondary = number of turns primary/number of turns secondary

Ground rods should be long enough to reach __________ moisture level of the soil?

permanent

The __________ at which work is done is power. The formula for this is:

rate, Power = Work ÷ Time

What is the formula for total current in a parallel circuit?

It = I₁ + I₂ + I₃ + I₄...

What is artificial respiration?

The forcing of air into the lungs of one who cannot breathe for himself.

The unit of electrical power is the __________ ?

Watt

Electrical energy is transformed into __________ when current flows through a resistor.

heat

What destroys transformers in an overload situation?

heat

What is the most common cause for lost power?

heat

One watt equals __________ horsepower?

.00134 1/746

How many windings does an auto-transformer have?

1

What is the resistance of 1000 feet of #10 copper?

1 Ohm

Name four ways that electric shock may effect the human body?

1. Asphyxia 2. Burns 3. Fibrillation 4. Muscle Spasm

What should be checked for when examining as injured person?

1. Breathing 2. Pulse 3. Head Injury 4. Paralysis on one side of the face 5. Laryngectomee 6. Stains and burns on or around mouth

What is the formula for resistance in a parallel circuit?

1/Rt = 1/R₁ + 1/R₂ + 1/R₃ + 1/R₄...

What is usually the maximum temperature the insulation in a transformer can stand?

221° F (105° C)

Codes require that the resistance of a driven ground shall not exceed __________ ohms.

25

Poles set on curves, corners, and strain points should be set __________ inches deeper.

6

Non-shielded cable use is restricted to what voltage?

7200

How many watts are in one horsepower?

746

What is a guy?

A brace or cable fastened to strengthen a pole and to keep it in position.

What is shock?

A depressed state of all body functions due to failure of the circulatory system.

A generator with only two slip rings is know as a:

A single phase generator (alternating current).

The unit of current flow is:

Ampere

What term represents the amount of current multiplied by the specific coil?

Ampere-turns

What are the specific resistance's of copper and aluminum?

Copper (Cu) 10.4 Aluminum (Al) 17.0 * 10.4/17 = .6118 ...approx. 60% conductivity of Cu

What are ways to control bleeding?

Direct pressure on pressure point and in extreme cases tourniquet.

__________ is the unit of measurement of work for mechanical power.

Horsepower

What is the unit of measurement of resistance?

Ohm

The overcurrent protective device on a CSP transformer is located where?

On the secondary side inside the tank between the secondary bushing and the secondary coil.

What is the formula to find total power in a parallel circuit?

Pt = P₁ + P₂ + P₃ + P₄...

What is the formula for power in a series circuit?

Pt = P₁ + P₂ + P₃ +P₄...

What is the formula for resistivity of a wire?

R = (K x L) ÷ A Where: R = resistance K = specific resistance L = length of wire in feet A = circular mil area

What is the mathematical expression for series resistance?

Rt = R₁ + R₂ + R₃ + R₄...

How do you find the circular mil cross section area of a wire?

Square the diameter of the wire in mills.

What precaution must be taken when freeing a victim from energized lines?

That is is deenergized

In a large-sized generator which conductors spin and which remain stationary?

The armature conductors are stationary and the poles revolve.

What is electric current?

The definite drift of electrons from a point of negative potential to a point of positive potential.

What is a watts definition?

The power used when one amp flows with one volt.

What is specific resistivity?

The resistance of a wire one mil in diameter one foot long.

Why are underground transformers and their bushings hermetically sealed?

To guard against moisture damage.

Why is filler paste injected into the sleeve?

To prevent oxidation to the splice.

What is the purpose of line hose?

To protect lineman from accidental contact.

What should be done to rubber gloves each time they are used?

Visually inspected, air tested, check for proper voltage (dielectric strength), check for ozone cutting and mechanical damage.

The unit of measurement of electromotive force is the:

Volt

One joule of work done in one second of time is one __________ of electrical work.

Watt

What is produced when a conductor is moved through magnetic lines of force?

an EMF is induced

A generator equipped with a commutator delivers __________ current.

direct

Transformers of less that 500 kva are called __________ transformers.

distribution * some texts use 200 kva, others 100 kva

Grounds for lightning arrestors should be __________ than 25 ohms.

less

The sheet iron core of a transformer forms a closed:

magnetic circuit

What moves the windings apart on a constant current transformer?

magnetic repulsion

How are the primary and secondary windings of a transformer coupled?

magnetically

Transformers of 500 kva and larger are known as __________ transformers.

power * some texts use 200 kva, others 100 kva

Which way does electric current flow?

negative to positive (Electron Current Flow) ...older texts used Conventional Current Flow (positive to negative) aka: Hole Flow, Positive Current Flow

Is there such a thing as a perfect insulator?

no

What type of series street light circuit uses only one wire?

open loop

Primary metering requires both __________ transformers and __________ transformers.

potential, current

The denominator of an improper fraction is __________ than the numerator.

smaller

A device used to convert AC power from one combination of voltage and current to another is called a __________ ?

transformer

Wood poles are classified by their:

1. Height 2. Top circumference 3. Circumference 6' from the bottom of the pole

If few electrons travel freely through a material, that material is said to be an _________.

insulator

Name three methods used to cool transformers?

1. Oil 2. Air 3. Water

The unit of electrical work is the __________ ?

Joule

What are the two types of underground cable?

1. Shielded 2. Non-shielded

Earth resistance is largely determined by what two conditions?

1. Chemical ingredients in the soil 2. Moisture present

What are the two types of counterpoise grounding?

1. Continuos (parallel) 2. Crowfoot (radial)

If a pole is set near an energized line what precautions should be taken?

1. Cover with protective equipment 2. Feeder holds 3. Rubber gloves

What are some signs of shock?

1. Increased shallow breathing 2. Cold clammy skin 3. Low body temperature

What does a good ground require?

1. Low resistance path to ground 2. Clean tight connections made at proper points 3. Adequate current-carrying capacity of grounding equipment.

How should shock be treated?

1. Maintain normal body temperature 2. Ensure adequate oxygen supply 3. Keep warm 4. Control bleeding if necessary lie down with head lower than feet 5. Do not move unless necessary

What does a CSP transformer have that a conventional does not?

1. Primary lightning arrestor 2. Primary protective fuse link 3. Overcurrent protection on secondary 4. Overload Signal lamp 5. External Operating handle for opening and closing secondary 6. No load tap changer

List two methods to test that the line is dead before installing protective grounds?

1. Rated and calibrated high voltage volt meter 2. Fuzzing: not an accepted safe method, you may not see or hear much of anything on lower voltage primary systems, especially on a windy day or at a noisy location. These lower primary voltages can be difficult to read on certain meters even...causing many linemen to bump the phase with the ground before coming on hard with the head/bill of the ground. Just in case a mistake was made, you could pull away easier.

Where will the primary fuse on a CSP be located?

Inside the tank between the primary coil and the primary bushing.

What is the formula for determining the total current in a series circuit?

It = I₁ = I₂ = I₃ = I₄...