Exam Flashcards
Who is the founder of IBEW?
Henry Miller in 1891
Changing taps on a xfmer
Taps can only be operated de-energized state and will step up or down voltage in 2.5% increments
Full load amps
Kva/coil ex. 37.5kvax1000
37500/7200=5.2A primary
37500/240=156A secondary
What are the two purposes of capacitors?
- Reduce line loss
- Improve power factor
Transformer polarity
8660v and 200kva and above= subtractive
8660v and 200kva and below= additive
What is a regulator and how does it work?
A device used to control circuit voltage by raising or lowering (buck/boost) voltage to maintain a constant quantity.
What is Back Feed?
Voltage passed from load side to source side
What is a reclosure and how does it work?
A reclosure is a device that senses and interrupts fault current and automatically restores service after a momentary outage.
How would you use a rotation meter and why?
You attach the small 3-phase motor to your secondary leads, mark leads accordingly, and after reinstalling the bank, ensure the customer has proper rotation.
What happens if an insulated boom contacts two phases simultaneously?
It puts the workers in series.
What’s on a tailboard?
Hazards associated with the job, special precautions, work procedures, energy source controls.
What is KVAR?
A measure of reactive power.
What is the function of a fused cutout?
It serves as a weak point to protect the lowside and isolate in a fault situation.
What is a sectionalizer?
A device that works in conjunction with a reclosure to sectionalize a section of a circuit. A sectionalizer will not open under load.
What are the two types of electrical contact?
Direct and indirect.
When can you enter a vault without forced ventilation?
When you have a sniffer/ air monitor 100% of the time.
What is guy length?
a² + b² = c² remove the amount of pole in the ground.
What is the minimum wraps on a wire drum
4 wraps.
What is voltage?
A force that pushes current.
What is Ohm’s Law?
1 volt will force 1 amp through 1 ohm of resistance
What is frequency?
The number of complete wave forms completed in one second unit of measurement.
What is Climbing Space?
A clear section of the pole to climb and avoid hazards.
What is EPZ?
A parallel shunt around the worker to reduce fault current across the worker’s body.
What happens when you ground one phase on a Delta System?
Nothing; you can ground one phase at a time.
How are Capacitors connected?
In parallel.
How many watts are in one horsepower?
746 watts.
What do the letters K and T represent in fuses?
K = Quick, T = Timed.
What must switches be timed for?
So there’s no excessive arcing.
What are the means of re-energization?
Lightning, Backfeed, Induction, Static, Accidental contact, Accidental re-energization
MAD
MAD values: 13.2 = 2’3”, 34.5 = 3’, 115 = 4’8”, 230 = 10’2”
What is considered high voltage?
High voltage is defined as 600 V
How is neutral defined?
Neutral is a current carrying conductor that is the return for system imbalance and must be macked out before cutting open.
How is guy tension calculated?
Guy length/anchor lead
X line tension
What are five things a lineman can do alone?
- Re-fuse cutout with hot stick
- Operate switch with handle or hot stick
- Install or remove hot tap (not dropping/picking up load)
- Remove load metering device
- Emergency repair to keep public safe
What is the fall protection requirement after 4’
100% fall protection
What is a not symptom of heat exhaustion?
Pale, waxy skin
How many bushings are on cans over 100 kVA?
4 bushings outside
What size transformer is needed for a 10 horsepower motor?
7460 = 7.5 kVA
Calculation: (746)(10)
What should you do before pulling a bayonet fuse?
Pull your bleeder valve
If someone breaks their lower leg, what should you stabilize?
Knee, ankle, broken end
How much weight can you put on a ladder?
2.5 times the weight of the ladder
What is Clearance?
Certification by the proper authority that a line has been de-energized and grounded. Locked out & tagged out.
How do you obtain a Clearance?
Contact dispatch, specify line/equipment and open points using 3 way communication
What is an eye splice good for?
90% of ropes breaking strength
What voltage and duration can fiberglass and wood withstand?
Fiberglass: 100,000 volts per foot for 5 minutes. Wood: 75,000 volts per foot for 5 minutes.
Why should transformers have similar resistance?
The less resistance can will take all the load and overheat.
What is a lightning arrestor?
Diverts over current to ground potential protecting the equipment in parallel.
How to take a capacitor offline?
-Open with load break tool
-Roll back high sides
- Wait 5 minutes
- Test, ground
- Shunt
How to take a Regulator offline?
Set to manual, shut off supervisory control.
- Step to neutral
- Verify neutral 3 ways (neutral light, hands on dial, testing)
-put controls to off
- Pull motor fuse
- Close bypass
- Open load & source sides.
Best sling configuration?
Basket.
Series street lights
6.6 amps
Ohms law
E=I(R)
