3rd Step Flashcards
1
Q
What is a distribution tap line?
A
A DTL is a distribution voltage line section that has a single source of supply, and can be isolated by a device having no more than once source and one load terminal.
Lines that are connected to a generating facility of any kind cannot be considered a DTL.
CAUTION: It must be specifically noted that a circuit section cannot be considered a DTL if the device used to energize the section is equipped with more than one source and one load terminal
Reference: DOM CO-1 SOB 301 3.3.1
2
Q
What information is required on a cable tag?
A
- Adjacent sectionalizing device position
2.Adjacent sectionalizing device number
3.Adjacent sectionalizing structure number - Next adjacent structure number (through structure)
- Footage to next adjacent structure
- Direction to next adjacent structure
- Operating voltage
Reference: DUG, IC 130.4.1
3
Q
What does a “qualified employee” mean?
A
An employee who by reason of experience of instruction is familiar with the operation to
be performed and the hazards involved.
Reference: APM Definitions
4
Q
What does a “qualified electrical worker” mean?
A
A qualified employee who, by reason of a minimum of two years training and experience
with exposed high-voltage circuits and equipment; and who has demonstrated by
performance, is familiar with the work to be performed and the hazards involved
Reference: APM Definitions
5
Q
What is the maximum depth of a trench that can be entered without shoring?
A
5 feet
Reference: APM Rule 146
6
Q
How many pipe straps are required per 10-foot section of riser?
A
3 straps
Reference: DUG, CR 110.1 note 7
7
Q
How many unistruts or kick blocks are required per 10’ section of riser?
A
2 - Above the 8 foot level
Reference: DUG, CR 110.1 note 8
8
Q
How soon should hazards be reported?
A
Employees shall immediately report any defective tool, apparatus, equipment or other hazards condition or work practice to the most available supervisor.
Reference: APM Policy P-18-A
9
Q
How often should high voltage rubber blankets be dielectrically tested/inspected?
A
Rubber gloves, sleeves, blankets, used on high voltage (above 600 volts) conductors and equipment shall be dielectrically tested at least once every six months and before being placed into service when received from the manufacturer. This equipment shall be marked with the date the dielectric test was conducted.
Reference: APM Rule 131.h
10
Q
What should be done when using rubber blankets on the ground?
A
Rubber blankets, when used on the ground, shall be protected from physical damage and moisture by means of tarpaulin, canvas or protective mat.
Reference: APM Rule 131.f
11
Q
What is the minimum amount of time to wait before entering an underground structure when new cable has been energized for the first time?
A
5 minutes.
Reference: APM Rule 303.c
12
Q
According to the APM, what shall be done prior to and after moving or bending any in-service cable?
A
The cable shall be carefully inspected before and after moving.
Reference: APM Rule 307.a
13
Q
When will the automatic circuit recloser on an underground circuit being worked be made non-automatic?
A
- Splicing or patching energized high-voltage underground cable.
2.Relocating energized high-voltage underground cable or equipment. - Filtering or replacing oil on energized high voltage underground equipment.
- Operating energized loadbreak components.
NOTE: In addition to the above requirements, supervisors in charge may make automatic circuit reclosers non-automatic whenever they deem it necessary for the safety of the employees performing the work
b. When employees are working inside an underground structure to make repairs immediately following a high-voltage failure, the automatic recloser of all energized circuits contained in that structure shall be made non-automatic. For those circuits not equipped with an automatic recloser device, a no test or hot line order shall be issued.
Reference: APM Rule 316
14
Q
Why is it necessary to use a live-line voltage tester?
A
To test normally energized parts of a circuit (as being de-energized).
Reference: APM 141.a
15
Q
What is a clearance?
A
A clearance is the formal authorization, officially issued to a qualified person, at that person’s request, to work on an electric line or some piece of operating equipment which is inherently too hazardous to work on while in service, and has been de-activated or de-energized, in a prescribed manner and placed in a safe condition to be worked on.
This authority carries with it a statement of the status of the line or equipment and is a guarantee that this status will not be changed in any way which might be detrimental to the safety of personel.
Reference: APM Rule 706
16
Q
When distribution personnel work inside a station, who takes the clearance?
A
Except as noted in paragraph d., the only person qualified to take a clearance for work inside a station from an operator, shift supervisor, or station electrician on duty at that station is defined as a person who has been designated as qualified by the division manager (or his/her authorized representative) having jurisdiction.
Reference: APM Rule 707.c
17
Q
Define a compound fracture.
A
Compound Fracture: In a compound fracture, the bone is broken and there is a connecting wound usually caused by the bone breaking through the skin.
Reference: APM Rule 1005.a.2
18
Q
What is the objective when administering first aid to a burn victim?
A
The objective of the first aid responder attending a burn victim is to relieve pain, prevent infection and treat for shock immediately.
Reference: APM Rule 1006.c
19
Q
What are the specific symptoms of a first-degree burn?
A
Mild to moderate pain.
Redness or discoloration
Mild swelling.
Skin warm to touch.
Rapid healing and little, if any, scarring.
Reference: APM Rule 1006.b.1
20
Q
Can 600 A plug-in terminations and components be removed by hand if they have been tested de-energized with a High Voltage Tester?
A
Live line tools are required for removing and installing plug in terminations except when complying with applicable sections of Rule 306
Reference: APM Rule 312.a
21
Q
Prior to a normal vault entry, for what is the structure’s atmosphere tested?
A
All structures shall be tested for oxygen (O2), combustible gas (LEL), hydrogen sulfide(H2S), and carbon monoxide (CO).
Reference: DOM, TE-13 2.1
22
Q
An SF6 gas switch - inside a vault - is suspected to have catastrophically failed. What additional atmospheric monitoring is required prior to entering this vault?
A
Testing for sulfur dioxide (502) is required where it is likely to exist. Sulfur dioxide may exist if a piece of SF6 equipment has failed catastrophically.
Reference: DOM, TE-13 2.1
23
Q
Is it permissible to pull cable with a cable grip near conductors energized at more than 300 volts? Explain
A
Yes, when observing the following:
When installing or removing underground cable in proximity to exposed conductors energized above 300 volts, adequate precautions shall be taken to prevent accidental contact between the cable, or metallic pulling devices, and exposed energized conductors.
Reference: APM Rule 308.a
24
Q
What depth should a CIC riser extend below grade?
A
CIC shall be installed with a minimum cover of 45 inches in commercial and residential areas.
Reference: DUG, Figure CR 120-1
25
Between grade and 8-feet high, what is the minimum size and schedule that is used for riser construction?
2½ inches, schedule 80.
Reference: DUG, Figure CR 110-1
26
When working in or around underground vaults, what protection must be taken at the entrance?
Adequate barricades or standard railings shall be used, unless the opening is constantly attended.
Reference: APM Rule 302.b 3
27
After de-energizing and before proceeding with the work on all power supply cables normally energized in excess of 600 volts, where should all conductors be short circuited and grounded?
1.Between the place where the work is being done and each possible source of supply,
or
2.at the work location, or
3.as close as practicable to the source of supply.
Reference: APM Rule 306.C
28
How many bushings do 25 kVA BURD transformers used for ferroresonance mitigation have?
1.6.9 kV BURD
2.9.5 kV BURD
a) 3 bushings
b) 3 bushings
Reference: DUG, Figure TX 300-14
29
What are the formulas used to calculate full load amps on both single- and three phase transformers?
1 phase FLA= kVa (1000)
V
3 phase FLA= kVa(1000)
V(1.73)
Reference: DDS-18, 3.0 and 4.0
30
30. Identify the four conditions required to create a potential for ferroresonance.
Four conditions are required to create a situation where ferroresonance might occur.
Unless all four are present, ferroresonance will not occur. The four conditions are as follows:
-The transformer or bank has phase-to-phase primary connections, or a wye primary with an ungrounded neutral (floating wye).
-Phases are energized or de-energized one phase at a time.
-Combined secondary load on the radial is insignificant compared to the primary cable lengths being switched.
-If the primary cable will be energized or de-energized one phase at a time; and the length of the cable is greater than or equal to the critical length as shown in Table 1 (Page 9), a ferroresonant condition may exist. Cable length is the total length (of the run, not the sum of all phases) of all cable in the circuit being energized/de-energized and is measured from the connection point to the end of the radial.
Reference: DOM, TR-8 Attachment 8-1
31
A switch may be considered de-energized for switching only when what conditions exist?
1. The switch contains only one circuit and is in a dead section of line as verified through the Switching Center.
2. Rules 309 b., c., d., e., f., and g. have been complied with.
b. Each step of routine or emergency switching shall be verified by two qualified employees at the work location.
c. For automatic circuit recloser operations (see Rule 316).
d. Locate, identify, and mark the position to be switched.
e. Check all the existing positions of the switch and compare to the circuit map, switch schematic, and cable and/or equipment tags to ensure that the switching order will accomplish the desired results.
f. If switching on a “RAC” type switch, a blocking device or special handle must be used to ensure that the switch is operated only to the desired position.
g. When switching energized underground single-phase fuses or disconnects in live front PMH type equipment, an approved protective shield shall be affixed to the grip-all stick. This also includes switching in single phase padmounted fuse cabinets. This does not apply to equipment where the fuses or disconnects are required to be de-energized (see Rule 304).
Reference: APM Rule 309.a
32
With regard to ferroresonance, describe and contrast the terms "cable length" and "critical cable length.
Cable length is the total length (not the sum of all phases) of all cable being energized/de-energized, and is measured from the connection point to the end of the radial.
Critical cable length is the total length per phase that is just enough to make ferroresonance a possibility when switched with unloaded transformers.
If the primary cable being energized or de-energized one phase at a time is of length greater than or equal to the critical cable length, then a ferroresonant condition may exist.
For multiple transformers being switched on a radial, the critical cable length is based on the total kVA being switched; for instance 150 kVA if switching three 50 kVA units.
Reference: DDS-2, 5.13
33
Name the four ways to eliminate ferroresonance, including design considerations.
The following considerations in design will eliminate ferroresonance in operation:
1. Use phase-to-ground primary connections prevent ferroresonance.
2. Energize/De-energize transformers and cables separately.
3. Use secondary load as a means to eliminate switches.
4. Sectionalize using gang-operated switches, when necessary.
Reference: DDS-2 5.13 B
34
Explain company policy concerning locking stations and enclosures.
All stations and gates to switch structures containing energized high-voltage equipment shall be kept closed and locked at all times except when a qualified employee has such station or structure under observation.
Reference: APM Rule 103
35
Explain how and when to address backfeed.
Before contacting the high-voltage (rated in excess of 600 volts) side of a de-energized transformer(s), or conductors connected thereto, all possible sources of backfeed shall be eliminated by disconnecting with an opening (opening primary or secondary jumpers, fuses, primary switches, cutouts, etc.), or by grounding and short circuiting the low or high-voltage side.
*open, or ground and short circuit*
Reference: APM Rule 149.a
36
What are the two types of materials used for vault covers? When would either be installed?
Cast-iron is used for traffic loading.
RPM is used for parkway loading.
Reference: UGS, 400.1 1.2
37
What are the characteristics of a 400-amp RAC switch?
The RAC switch will have four or more ways.
The RAC switch may be manually operated or spring operated.
It should be noted that the far left position has only two attitudes (Open-Bus) while the remaining positions have three attitudes (Tie-Open-Bus). This creates the capability of electrically tying two adjacent positions together without using the bus
Reference: DOM, SW-3 Attachment 1
38
Explain the periodicity requirements for atmospheric monitoring of underground structures (including logging of results).
Immediately prior to an employee entering, and continuously while occupied.
Results shall be logged initially and at least every 4 hours thereafter
Reference: APM Rule 301.D
39
According to the APM, when are blocking devices required during switching?
If switching on a "RAC" type switch, a blocking device or special handle must be used to ensure that the switch is operated only to the desired position
Reference: APM Rule 309.f
40
Per EN-1, if there is an oil spill who must be notified, and when?
Supervisors must contact the on-duty TDBU Environmental Specialist for ALL spills/
releases within one hour of the supervisor's knowledge of the event.
Reference: EN-1
41
. Under what conditions should a portable gantry be available for use?
Rescue apparatus shall be readily accessible when entering all underground structures with a depth greater than 4 feet.
Reference: APM 1024
42
What are the characteristics of a 400-amp RAK switch?
The RAK switch is a four-way, three-position switch with operating characteristics similarto the RAC.
The difference being that the No. 1 way is connected solid to the bus. Thereare, therefore, only three switched positions. The No. 2 position has only two attitudes (Open-Bus). remaining positions will have open, tie, bus. This switch will normally be applied to a 4 kV system (7.5 kV voltage class switch).
43
What are the characteristics of a 600-amp RAM switch?
The RAM switch may be a two-, three-, four-, five- or six-way switch. The RAM switch
may be manually operated or spring operated
44
Describe the application of the RAG switch
RAG switches provide an internal grounding attitude on each switchable position. These switches were developed to simplify the grounding procedures utilized when crews work on underground conductors.
Reference: DOM, SW-5 Attachment 2
45
How many pipe straps are required per 10-foot section of riser or conduit, when attaching directly to the pole?
3 straps.
46
What is the maximum distance between unistruts, when attaching a riser?
Maximum of 5 feet apart, above the 8-foot level.
47
How far should a BURD enclosure's top cap extend above finished grade?
2 inches.
48
What is the purpose of spiking a cable?
Cable spiking is required to prove the cable de-energized when no other method of testing exists at the work location.
49
Provide two examples of when spiking a cable might be required.
Examples when spiking may be required but not limited to the following:
* A dig-in (main line, or tap line)
* Adding components (J-Bar, 600 ap T-Body [hammer])
* Blown component
* Lead Cable System
50
Under what conditions is it permissible for an employee to enter an underground structure without anyone else in attendance?
1.There are no energized cables or equipment in the structure, and;
2. A protective device is placed around the opening, and;
3. Forced ventilation is provided
50
List and describe the steps for grounding, when replacing cable after a dig-in. The damaged cable is between the pothead and the structure.
1. Identify the circuit (using circuit map(s), cable tags, perform amp check, consider cable size, direction of cable, structure numbers).
2. De-energize, take clearance and eliminate backfeed.
3. Prove pothead(s) de-energized, and float the potheads and isolate the concentric.
4. At the other end of the cable, prove the cable de-energized, isolate cable and concentric.
5. If contact with the damaged cable/conductor is required, expose the area around dig-in location and remotely spike/cut the cable at dig-in location to prove it deenergized. If minimum approach distance cannot be maintained from exposed conductor, use a testing device (for example, approved high voltage tester/indicator, Wemco), and test the cable de-energized, then use a spiking tool to prove the cable de-energized.
6. Replace cable.
51
What is the function of a ground adapter device (GAD)?
Provides a method of grounding a de-energized section of underground cable that is equipped with separable 600 A components, using live line tools.
52
What is a USA, and when would it be required? What company provides SCE with USA service?
USA = Underground Service Alert. USA information is provided to SCE by DigAlert. State of California Government Code 4216 mandates that anyone doing excavation work shall call at least two working days prior to commencement of any excavation. If you are performing this type of work in California or Nevada, please call Underground Service Alert at (811) or (800) 227-2600.
53
Describe what PMH and PME are. How are they different?
The PMH is a 2- to 4-compartment cabinet 3-pole, 600 A, gang-operated load-break switches, 3 single-pole 200 A air load-break fused disconnect switches, direct bus terminations, or a combination of these devices. The switches and fused disconnect switches are each in separate compartments. Underground cable is used to connect the switches and disconnects.
PME switchgear is similar except that it is completely dead-front construction and utilizes load-break elbows instead of single-pole disconnect switches.
54
Is it possible to determine, from a circuit map, if entry into an underground structure is restricted? What is required to restrict entry into a structure?
Yes. Restricting entry into a structure requires (1) placement of two postings in the affected structure, (2) notification of the Switching Center, and switching center will create a (3) revision of the circuit map.
55
Provide two examples of when conduit brushes or mandrels should be used.
Rough or rusty interior surfaces, sand, gravel or other foreign material in the conduit, or
protruding grout at joints are typical unfavorable conditions.
56
When pulling multiple cables, why should the pulling attachments be kept even?
Do not stagger the cable ends or the pressure from the leading cables may cause the nose of the trailing cable to dig in and block the pull.
57
What actions are taken following a spill of lubricant, during cable pulling evolutions?
If cable lubricant is spilled, it should be washed, swept or squeegeed from the floor using wet mops. Outside, spills should be covered with sand, dirt or gravel. For more details, see the individual Material Safety Data Sheet (MSDS).
58
Describe what is meant by "slack pulling." Is it a preferred method of pulling cable?
Slack pulling is where the pull is stopped and started to accumulate slack in the cable.
Slack pulling is not recommended, but may be used as a last option.
59
For what type of street lighting system are constant-current (regulated output (RO)) transformers used?
Series streetlight circuits are supplied by constant current or Regulated Output (RO)transformers which deliver a constant current of 6.6 A.
60
What is the specified loading range for RO transformers?
RO transformers should be loaded to a minimum of 60 percent and a maximum of 100 percent of their nameplate rating.
61
What is the range of wattages in which Mission Bell streetlight luminaires are available?
70 - 400 watts.
62
For what situation, primarily, is EPR cable used? Why?
PILC-substitute cable is a 3/C EPR-insulated, copper cable designed for replacing failed or deteriorating 3/C PILC (lead) cable in existing ducts. To minimize cable diameter, tape shields and solid copper ground conductors are used instead of the concentric neutrals common to other polymer (for example, CLP) cable designs.
63
Is it permissible to construct a three-phase bank with three single-phase, fused, BURD transformers? Why or why not?
Fused BURDs may be used in banks. However, do not use fused BURD transformers in closed delta banks.
64
What is the purpose of a load-break fuse cabinet (LBFC)? What type of fuses do they use?
This fuse cabinet provides a method for fusing 6.9 kV or 9.4 kV residential radials with parallel current-limiting fuses.
64
How often should gas and oxygen monitors be tested for calibration/certification? How are the calibration records handled?
Monthly.
The calibration records for the monitor are included in the Foreman's Inspection Report and are kept on file at the service center.
65
May PMHs or PMEs be used to de-energize capacitor banks? Explain.
No. PM and PME switches cannot be used for capacitor switching. A sign reading "Capacitor Bank No. Source-Open Capacitor Bank Switch Before Opening This Switch" shall be placed on the compartment door of all PMH/PME switches used to feed capacitor banks.
66
After replacing the fuses inside a LBFC, what is the sequence for energizing the cabinet?
After fuse replacement, the fuse cabinet shall be energized with the line side load-breakelbow first. Then the load side load-break elbow will be used to pick-up the load.
*Pick up or drop load on the LOAD side*
67
The 4 kV oil fuse cutouts have become obsolete in SCE circuits. Provide an example of when they should be replaced, and what types of fusing they should be replaced with.
The obsolete oil fuse cutout should be replaced whenever an opportunity exists to do so.
For example, during major construction work or during any planned power outages Oil-fuse cutouts may be replaced with MVS switches, MCAN fuses, or MCLF fuses.
68
How tight should the basic insulating plug (BIP) be installed on a 600 A component?
Use a torque wrench to apply 50 - 60 ft-Ib of torque when tightening.
69
How is a 600 A basic elbow connected to another 600 A basic elbow? How is a 600 A basic elbow connected to 200 A elbow?
Connector plugs are used to connect 600 A components
Reducing tap plugs are used to connect 600 A components with 200 A components.
70
72. When making up secondary Utilco connections, is there a torque specification for the setscrews? If so, what is it?
Yes, a minimum of 25 ft-Ib. (tighten it twice)
71
. What cable sizes are Utilco connectors featuring two setscrews designed to fit? How many ways are these connectors available?
4/0 - 700 kcmil.
Available in 4-way and 6-way types.
72
How many sizes are available of heat shrink sleeves for splicing CLP secondary cables? For what range of cable sizes is each shrink designed?
Two different sizes:
6-inch long type is used for #2 - 350 kcmil cables;
9-inch long type is used for 350 - 750 kcmil cables.
73
What is the purpose of the Raychem wraparound sleeve repair/sealing kit? How are they applied?
These kits are used for repairing cracks and splits in secondary cable, including direct buried, and in sealing secondary connectors in wet or congested structures. These "wraparound" sleeves may be installed without cutting the cable or disturbing the connector. The silicone gel seals on contact.
#2-500kcmil
6" and 10" length
74
If splicing CLP is required, what is the preferred method? What is the alternative method, and when would it be used?
Whenever possible, use pre-molded rubber splices in lieu of hand taping. Use taped splicing only if pre-molded components are not available.
75
What color is the bushing that is installed - on J-bars and equipment - for landing 12 kV load-break elbows?
Solid red. However, some older versions of this bushing insert may have a red, yellow, or gray color-band on the bushing insert surface that mates to the load break elbow. While some older units may not even have color-bands. Be sure to use the correct voltage load break bushing insert.
76
When are ELR and RLR elbows used?
Not for use on systems above 12 kV. Standard elbows should be used whenever possible. Repair (ELR) and Replacement (RLR) elbows shall only be used if standard elbows cannot be used. The ELR and RLR elbows are not to be used for general elbow replacement.
The ELR elbow provides an additional elbow length of approximately 3 inches, and the RL elbow provides an additional elbow length of approximately 10 inches. ELR and RLR elbows may be used as follows:
ELR Elbows: Use for replacing damaged or blown standard load-break elbows.
Replacement (RLR) Elbows: Use when a longer length elbow is required, such as when live-front equipment is replaced with dead-front equipment (for example, PME switches or minipad transformers).
77
What color is the bushing that is installed - on J-bars and equipment - for landing 16 kV load-break elbows?
The latest version of the 25 kV Class bushing inserts are supplied in a solid blue color. Older versions of this bushing insert may have a red, yellow, or gray color-band on the bushing insert surface that mates to the load break elbow. Some older units may not have color-bands. Be sure to use the correct voltage load break bushing insert.
78
Why must pad-mounted transformer casings be sealed to the pad-mount they rest upon?
The gaps between concrete pads and pad-mounted equipment shall be sealed to prevent a wire from entering from the outside into the compartment with exposed live parts. This will also prevent tampering, reduce moisture entry and deter rodents and vermin from nesting inside the equipment after the equipment is closed and locked.
79
What is the definition of a "confined space?"
A space that has all of the following:
1. Is large enough that an employee can bodily enter; and,
2. Has limited openings for entry or exit; and,
3. Is not designed for continuous employee occupancy.
80
What is the definition of an "other confined space?"
Other confined space is a space that meets both of the following conditions:
1. Existing ventilation is insufficient to remove dangerous air contamination, oxygen enrichment or deficiency that may exist or develop, and,
2. Ready access to or exit from the space for the removal of a suddenly disabled employee is difficult due to the location and/or size of the opening(s).
81
How long are atmospheric monitoring logs retained?
One year
82
Is it permissible to remove fuses from energized underground equipment?
No. The fuses in underground equipment shall not be installed or removed until de. energized (this does not apply to fuses designed to interrupt load) and then only with live line tools or after grounding by approved methods
83
What type and size fuses are used in single-phase 12 kV BURD transformers of the following sizes:
a) 25 kVA
b) 50 kVA
c) 75 kVA
d) 100 kVA
Current-limiting fuses are used in these transformers.
a) Size 6
b) Size 10
c) Size 18
d) Size 20
84
For what applications are MCAN and MCLF fusing options designed?
MCAN: ≤ 80 A
MCLF: 100 - 180 A
85
Describe how fuses are replaced in a MCLF fuseholder.
Fuse replacement is performed by completely removing the well stud and setscrews inside the 200 A bushing well to separate the end fittings from the encapsulated fuse Use a ½" socket to remove the stud. Then use a 3/8" socket drive tool (supplied with replacement fuse to remove setscrew.
86
Why is it important to verify the line and load bushings on BURD equipment, when replacing/installing fuses? How is this performed?
Known manufacturer defects in the internal wiring of some BURD equipment could lead to inadvertent arcing during fuse removal/installation.
To ensure the proper marking and relative location of fuse chamber and switch mechanism, the following test should be conducted. To conduct these tests, the fuse chamber must be empty and the switch open. A conductor such as a length of No. 4 bare wire may be used to make contact with the internal fuse contact. It should be noted that the "R" positions might be connected to either the top or the bottom fuse chamber contact.
The switch must be de-energized and completely disconnected from the distribution system prior to conducting this test.
87
Prior to operating a BURD switch, how is the switch's position verified?
Verify the indicated position by checking the voltage at test points and the switch schematic if possible.
87
Define and contrast the terms "manually operated" and "spring operated," relating to underground switches.
Manually Operated - the handle is directly connected to the operating shaft. (The speed of the contacts is controlled by the operator.)
Spring Operated - the handle is connected to the operating shaft through a spring mechanism. (The speed of the contacts is not controlled by the operator.)
88
What precautions must be taken prior to energizing any new piece of cable or equipment?
A.No new piece of cable or switching device shall be energized until it has been positively identified by tags or other approved marking procedures.
B.No piece of equipment shall be energized until all terminals, cables, and positions have been safe ended, end belled, or otherwise protected in a way that would prevent a short circuit, ground or personal contact.
89
What is the recommended size/type of cable to be used with 16 kVA BURD switches?
1/0 CLP cable
90
Is it permissible to stack a 200 A tap on a 600 A termination located on a pad mounted RAM gas switch?
Yes. One 200 A tap may be stacked on each 600 A cable termination.
91
When monitoring gas pressure on a G&W gas switch, is the reading affected by ambient temperature?
An SF6 switch must have at least 5PSI to be operated
Units manufactured after 2010:
No. G&W gauge pressure is temperature compensated, and does not vary with temperature.
Units manufactured before 2010:
Yes. G&W gauge pressure is not temperature compensated. Ambien temperature must be factored into the reading
Pre 1986 joslyn switches SHALL NOT be operated, they have a white and red gauge (no green)
92
During a pre-switching inspection, a gas switch's gauge glass is found to have moisture intrusion, and the pressure reading is inconclusive. How is this situation addressed?
If the pressure gauge on a switch is found defective (that is, moisture intrusion or damaged glass), verify that the switch tank pressure is above 5 psi by installing the master pressure gauge onto the switch fill-valve.
93
Describe the process for conducting a routine inspection of a 4 kV oil-filled cutout.
Inspect each oil-filled fused cutout as follows:
STEP 1. Visually inspect the cutout body and cables for oil leaks, cracks and loose screws.
STEP 2. Check the temperature of the cutouts by using the heat-sensing instrument described in Reference 3.6 (Page 1). The temperature of the cutout should be no higher than 10 degrees Fahrenheit above that of adjacent cable.
STEP 3. Check and add oil as required.
94
What conditions are checked during an external inspection of an underground switch? External inspection shall consist of the following:
Performing thermal scan for hot spots per Reference 3.10 (Page 1)
Inspecting for signs of corrosion, oil leakage, and/or damage
Inspecting weld seams
Inspecting external operating mechanism
Inspecting operating shaft seals
Inspecting gaskets (cover, cableheads)
Inspecting oil-fill plug and sight gauge seals
Inspecting tightness of bail tabs (200 A positions)
Inspecting oil level
Inspecting condition of marine-coating
Inspecting fuse carriers for proper locking and sealing
Verifying that switches are mounted properly; for example, that all bolts in the wall and steadilegs are in good condition
95
Prior to operating any switch or BON fuse in a single-phase or three-phase pad-mounted transformer, what two precautions must be taken?
Before operating any switch or BON fuse in a single or three-phase pad-mounted transformer, which is either energized or about to be energized, the pressure-relief device shall be operated to relieve internal pressure and the oil level must be verified on the oil-level indicator to be adequate.
96
When inspecting underground switches, the operating mechanism(s) should be operated how many times in order to verify functionality?
5 times.
97
Describe how to operate a pad-mounted transformer tank's pressure relief valve.
Operate transformer tank's pressure relief valve as follows. Use hot stick for energized
operation.
1. Pull pressure relief valve open, keeping it held open until pressurized air can no longer be heard hissing through the valve, and then for another 30 seconds allowing any residual pressure to be removed from the tank.
2. Close pressure relief valve and wait 30 seconds.
3. Pull pressure relief valve open, keeping it held open until hissing stops and then for another 5 seconds allowing any residual pressure to be removed from the tank.
98
What is the purpose of the CLF on the primary of pad-mounted transformers?
The primary of a pad-mounted transformer equipped with BON fuses also contains additional internal current limiting fuses (CLF). These CLFs are designed to operate on high- fault currents caused by internal transformer failures. CLFs are not field replaceable
99
Describe how to mark the structure number on a pad-mounted transformer.
All pad-mounted equipment shall have the structure number permanently affixed using Scotchlite decals. The structure number shall be installed in the upper left-hand corner of the pad-mount door. Additional Scotchlite numbers may be placed in other locations to assist in locating equipment not easily seen, for example, on the back of a transformer only visible from the street.
100
What marking requirement exists for pad-mounted transformers equipped with a tap changer?
Pad-mounted transformers with external tap changers in cabinets will require a decal stating "DE-ENERGIZED OPERATION ONLY" near tap changer.
101
What are the clearance requirements for installing 12/16 kV three-phase subway transformers?
A minimum clearance of 3 feet shall be maintained on the back and sides of the subway transformer. A minimum of 8 feet shall be maintained in front of the transformer in order for the crews to operate the transformer safely.
102
Why do we ground?
Grounding is required for the protection of the worker when working without live line
tools or approved rubber gloves on de-energized high voltage line or equipment.
102
Describe the procedure for sealing a pad-mounted transformer.
A. Clean around the concrete pad and pad-mount to remove any dirt or debris in order for the sealant to adhere properly.
B. Before applying sealant, carefully follow instructions on the cartridge. Open sealant by cutting at a 45 degree angle at the 1/2 mark.
C. Apply sealant completely around equipment between the concrete pad and in the "pad unistrut."
D. Larger gaps or holes may require the use of concrete mortar or steel plates.
103
What are the key steps in the grounding process?
The key steps in the grounding process are:
Conduct an active tailboard
Determine grounding requirements
Inspect grounds before use
Clean ground connections
Test conductors de-energized
Apply proper grounds
Remove grounds
104
What is the preferred method of grounding?
Equal potential bracket grounding is the preferred method for all situations. This method
requires a set of grounds between the worksite and every source of supply. In addition,
an equal potential zone (workspace) shall be created at the worksite. Equal potential
bracket grounding applies to any type of structure.
105
Can the second set of grounds be installed by hand?
No employee shall handle any conductive portion the grounding device while it is being
installed or removed from the conductors, except when using the live line tools.
106
What is the function of the Rocker Arm Bus (RAB) grounding tool?
Designed and built by SSID for grounding an oil switch bus directly using live line tools after draining the oil where the switch positions cannot be grounded by any other means. Multiple size end pieces are available for RAB tool to be used for different size switch buses.
107
What are the grounding options for handling the concentric when replacing a transformer using the underground isolation method of grounding?
1. Completely isolate the concentric at the source, or
2. If the concentric is not isolated at the source, then the concentric of at least one phase should remain connected to the structure ground at the work site to eliminate hazardous difference of ground potential.
107
What is the definition of a pothead tap (according to the DUGGM)?
Wires that connect the cable to the overhead conductor. Pothead taps are the conductor jumpers that are connected from the pothead (cable termination) to the overhead conductor line.
108
State at least three variables that dictate the manner in which work and grounding are accomplished in underground structures.
1.The specific types of components, terminations, joints or junctions.
2. The decision of working underground components with or without live-line tools.
3. The characteristics of the system or equipment to be worked.
4.Available fault current duties and the proper ground sizing (Table 3.1).
5. Elimination of hazardous differences of electrical potential.
6. The requirement to maintain minimum approach distances or use appropriate high voltage cover while working near unprotected energized conductors and/or equipment.
7.Application of an Equipotential zone (EPZ)
109
. Define Current, Voltage and Resistance. What is the formula that defines the relationship of Volts, Amps and Ohms in a DC circuit? Using this formula, what happens to current if the voltage decreases?
Current: The flow of electrons through a circuit. Current is measured in amperes
(amp). Amperage is the rate of flow of electrons.
Voltage: The driving force that makes electrons flow through the circuit. It is
measured in volts (v). Common sources are batteries and generators
Resistance: The electrical quantity that opposes the flow of electrons. It is the
difficult encountered in trying to push electrons through matter. It is measured in
ohms. All matter offers some resistance. An insulator offers a great deal of
resistance while a conductor offers little resistance.
E= Ix R where:
E: Electromagnetic force (volts)
I: Intensity of current (amp)
R: Resistance (ohms)
Current decreases if voltage decreases
110
What is the difference between Alternating Current (AC) and Direct Current (DC)?
Alternating current flows in two directions, forward and backward.
Direct current flows in only one direction from the negative terminal to the
positive terminal.
111
The houses below are supplied by a 120 V source, would the house at the end of the circuit have a higher, lower or equal voltage to the first house in the circuit
House 3 would have an equal voltage in a parallel circuit.
112
Referring to the previous question, what can be said of the current supplied to each home given that each home has a different amount of load, but the same voltage supplied?
Each home has a different current flow proportional to the load
113
What is backfeed? How can you protect from backfeed?
A source of supply from the load side of the electrical system to a de-energized section of line, apparatus or equipment.
Before contacting the high-voltage (rated in excess of 600 volts) side of a deenergized transformer(s), or conductors connected thereto, all possible sources of backfeed shall be eliminated by disconnecting with an opening (opening primary or secondary jumpers, fuses, primary switches, cutouts, etc.), or by grounding and short circuiting the low or high-voltage side.
When short-circuiting at the customer panel, shunts shall be connected to each phase, the neutral and the customer ground
114
What is the purpose and application of the Ground Assembly Rotation Program?
GARP ensures that ground assemblies are routinely maintained. No ground assembly should ever exceed 24 months in the field.
115
Grounds are to be inspected before each use. What should you look for while performing a ground cable inspection?
Inspect the ground cable for cuts, nicks, and abrasions that may have penetrated through the jacket into the conductor and, if suspect, inspect the conductor for broken strands or visual signs of corrosion.
Inspect for kinks that could possibly damage the strands.
Ensure ground cable is not damaged, for example, (flattened).
Inspect for swollen cable jacket or soft spot for indication of internal corrosion or damage to strands.
Verify the GARP test date is current. (That is, within 24 months of test date)
116
Discuss why a ground wire is installed in a vault standpipe vent.
To assist in underground structure locating from the surface, install a #6 bare copper wire from inside the vent pipe to the structure ground system. This installation will allow a single person crew to tie into the system ground and locate the facilities unaided. The installation shall be made to a minimum of one vent per vault during new construction, added to the appropriate structures during the routine maintenance cycle or as the need arises by request for assistance from the contract cable locating company.
117
What are the structure grounding requirements for pullboxes?
One ground rod is required in all pull boxes where primary cable is installed, except those pull boxes that have bare copper ground wires laid along with the conduit.
117
Prior to 1983, vault structure grounds were installed near the floor of the structure. Since then, they have been installed near the top of the vault. Why?
Prior to 1983 the ground bus was installed near the floor in manholes and vaults. Since then, provisions for installing and grounding the bus have been provided approximately 4 inches below the top of the structure. The purpose is to minimize the effect of corrosion on the ground bus.
118
What is the minimum size and type of conductor for connecting vault equipment to the structure ground bus?
Ground all equipment to the ground bus using #2 str bare copper (minimum).
119
Describe how to inspect a BURD transformer for signs of overheating?
Check for overheating of primary connections (signs of burning or arcing) and secondary connections (signs of discoloration). Check for hot spots and for signs of excessive heating (discoloration of paint or paint blistering) of tank surfaces
120
What actions should be taken if soil/debris is found inside a BURD enclosure?
1. Verify if additional structures on the radial require pumping and, if so, schedule outage and pump truck accordingly.
2.De-energize all structures requiring soil/debris removal.
3. Inspect for oily debris or smell. If oily debris is found, refer to the removal policies and procedures detailed in EN-1 of the Environmental Policies and Procedures (EN) Manual.
4.Inspect how soil/debris entered the structure and make any necessary repairs.
5. After soil/debris removal is completed, (1) verify there is no "red eye": (2) check the gas pressure; (3) ensure all terminations are seated properly; and (4) complete any other maintenance while de-energized (for example, cable tagging).
6. If any of the conditions in steps 1 - 5 are found, ensure the DIMP process is followed and entered in the Field Tool (for example, P2 or E1,P1)
121
Describe the procedure used if a lineman on a pole is unconscious from electrical contact.
1. Call the switching center on the radio and declare an emergency using the orange button.
Give the nature of the injury, address/location, radio or phone number you are calling from to the switching center
3. Clear any electrical hazards or imminent danger to prevent further injuries to victim or crew
4.Once all hazards have been cleared, ascend the pole to the victim
5. Take the hand line snap and wrap around the cross arm two times
6. Take enough rope to wrap around the victim. Secure the rope under the armpits and tie three half hitches
7. Drop the hand line sheave and hook, take the hand line and slowly lower the victim to the ground.
122
