JL Exam Flashcards
What is a recloser? How does it work?
A recloser is a self contained device that senses over-currents to time and interrupt fault current and to re-energize the line by reclosing automatically. If a fault is permanent, the recloser locks open after a preset # of operations (usually 3 to 4).
What is the proper procedure in obtaining a clearance on a line or equipment?
Identify yourself, who you work for, give location, and purpose of work. Identify energy source controls, isolating devices, and opens that are tagged. Dispatch will repeat this info back to you. If correct, they will issue the clearance with a # and time of issuance.
List in order, the proper steps to remove a regulator from service.
1.) Switch to manual, turn of scada/switch to local
2.) Buck or boost to neutral
3.) Verify regulator is in neutral with three tests. 1) neutral light is on 2)drag hand dial is in neutral position 3) test voltage between the source and load bushings, if no potential difference(a reading of zero) then the regulator is confirmed to be in neutral.
4.) Lock in off position, remove motor fuse
5.) Close bypass
6.) Open source & open load
What are the methods used for sagging wire?
1.) Dyno
2.) Transit
3.) Targets
4.) Jerk
5.) Cornfield
What is the function of a fused cutout?
A fused link that will open up in over-current situations such as fault current to help protect downstream devices.
When and why is capacitance a concern when working with an underground cable?
Capacitance is a concern when an underground cable has been de-energized but not yet grounded. Before it is grounded the cable still holds a capacitive charge. This is because underground cable is built exactly like a capacitor, It has two conductors separated by insulation that allow it to hold a capacitive charge
Explain when you would use a rotation meter and the proper procedure for using it.
You would use a rotation meter when replacing a transformer bank or paralleling banks together to ensure the customer receives proper rotation for their equipment. Before de-energizing the bank you must check rotation. To do this, connect the leads of the rotation meter to the hot legs in a left to right Red,White, Blue order and remember what rotation you got with that configuration.
When the new bank is installed but before energizing the secondaries, you must check rotation to ensure it matches the old bank and tape the new hot legs accordingly. Once this is done you can connect the secondaries to the corresponding hot legs. Red-Red, White-White, Blue-Blue.
What is the main reason for grounding transformer cases?
To keep the transformer case at ground potential. Without it the case would be energized at primary voltage.
Define climbing space
An open quarter of the pole, free of obstructions, allowing the worker to move up and down more freely.
Describe EPZ grounding and how it is done?
EPZ grounding is using grounding and bonding leads properly sized for the anticipated fault current and placed in such a manner to keep everything the worker can touch in a working position, at the same potential. This will help provide a low resistive path to ground to shunt most of the fault current around the worker.
What is a sectionalizer? how does it work?
A sectionalizer is an automated switching device that is used to isolate faults and is typically used in conjunction with an upstream recloser. The sectionalizer will isolate the line downstream of it before the recloser closes back in for the 3rd and final time. The sectionalizer keeps the recloser from opening back up and cuts the outage radius down
Describe the procedure you would use for grounding a 3 Ø 4 wire primary on a wood structure.
Assuming you have been issued a clearance and the line has been identified, isolated, and tested. Next you would install a cluster bracket below your feet while in a working position. Next you would install a ground from the cluster bracket to your neutral, then a ground from the cluster bracket to center Ø with an insulated hot stick, then from center Ø to the next nearest Ø, and finally from center Ø to the last remaining Ø
Who is responsible for safety on the job?
Everyone on the job including you!
What is the basic formula for the depth of poles in normal soil?
10% of the poles length plus 2 feet.
Minimum of 5’
A current flowing through a 3,650 ohm resistor is 7.7 milliamps. What should a voltmeter read when connected across the resistor?
3,650 x .0077= 28.105
(Divide by 1000 to get from mA to A)
