Substa on Electrician Appren ceship Category E: EHV
Maintenance Ques ons and answers Newest RATED A+
2025/2026 NEW!!
Please list the 6 major categories of discussion for any tailboard.
a. Methods of emergency no fica on
b. What is our job plan?
c. What is energized? What is not? What are the clearance points?
d. What are the hazards associated with the job?
e. What are the assignments, groups or individuals?
Special precau ons, special equipment, PPE?
g. Does everyone understand/ask ques ons?
What are the major categories of a Substa on Maintenance switching tailboard?
a. Methods of emergency no fica ons
b. What is our switching assignment?
c. How will we accomplish the switching?
d. Have I verified equipment to be opera onal?
e. What are the hazards involved/ PPE required?
f. What are my clearance points?
g. Are grounds installed? If so, where?
What are the basic safe work prac ces observed in a 230KV or 500KV receiving sta on?
Check in to sta on upon arrival, close and lock gate a2er entering. Maintain MAD for personnel
and equipment as well as safe working clearances at all mes 500KV- PTG 11'11"PTP
19'9"230KV- PTG 5'8"PTP 9'2"115KV- PTG 3'4" PTP 4'7" 69KV- PTG 2'11" PTP 3'9" PWalk down
yard and visually inspect for damaged equipment or missing/broken grounds.tailboard with
other crews in working in the same area. Maintain speed limits and follow roadways.
What insula ng mediums are used in EHV breakers?
SF6 gas, ultra-dry high pressure air, polymer, ceramics, air, epoxy, silicone
What does a WIKA gauge measure?
WIKA is a brand. Usually, it is measuring gas pressure.
, What is the minimum % of gas density that SRP allows in an EHV breaker?
98% on all new breakers,98% on Palo Verde Breakers, 97% on all other voltage class breakers
including older 500KV breakers.
Is SF6 gas harmful and or a hazardous material?
Yes, it displaces oxygen and can create a toxic substance when used to suppress an electric arc.
It is invisible, odorless, and tasteless.
Explain the difference between a live tank and a dead tank breaker.
A live Tank breaker has external energized tanks that are isolated from ground. These tanks
contain the interrup ng contacts, which are above ground poten al.
A dead tank breaker has their interrup ng contacts enclosed in tanks that are at ground
poten al.
What type of EHV breaker has a free standing C.T.?
A live tank breaker.
Preventa ve breaker maintenance consists of what?
Tailboard and be working under a grounded clearance. Power factor test, ductor/micro-ohm
test (the resistance of closed contacts, ming test ( opening and closing) , checking moisture,
purity and density of SF6 gas (and content of SO2 if any), pressure switch seHngs, service the
compressors (oil change and belt checks, pump mes), check heaters, mechanism travel
measurements, alarm checks ( low gas and low gas lock outs, motor trouble/fail) , and an
inspec on of the overall condi on of the breaker.
Name the different types of opera ng mechanisms and explain the safety hazards associated
with each.
Air Hazards include: pressurized containment vessel, air leaks are not visible, fiHngs, hoses,
regulators and air tools need to be rated for the pressure to be applied, beware of moving parts,
drain air pressure before performing maintenance.
Hydraulic hazards: pressurized containment vessel, containment vessel has a nitrogen pre-
charge pressure even a2er hydraulic pressure has been drained, hydraulic oil is flammable,
beware of moving parts, drain hydraulic pressure before performing maintenance.
Spring hazards: beware of moving parts, discharge spring pressure before performing
maintenance, spring can be charged in both open and closed breaker posi ons.
Maintenance Ques ons and answers Newest RATED A+
2025/2026 NEW!!
Please list the 6 major categories of discussion for any tailboard.
a. Methods of emergency no fica on
b. What is our job plan?
c. What is energized? What is not? What are the clearance points?
d. What are the hazards associated with the job?
e. What are the assignments, groups or individuals?
Special precau ons, special equipment, PPE?
g. Does everyone understand/ask ques ons?
What are the major categories of a Substa on Maintenance switching tailboard?
a. Methods of emergency no fica ons
b. What is our switching assignment?
c. How will we accomplish the switching?
d. Have I verified equipment to be opera onal?
e. What are the hazards involved/ PPE required?
f. What are my clearance points?
g. Are grounds installed? If so, where?
What are the basic safe work prac ces observed in a 230KV or 500KV receiving sta on?
Check in to sta on upon arrival, close and lock gate a2er entering. Maintain MAD for personnel
and equipment as well as safe working clearances at all mes 500KV- PTG 11'11"PTP
19'9"230KV- PTG 5'8"PTP 9'2"115KV- PTG 3'4" PTP 4'7" 69KV- PTG 2'11" PTP 3'9" PWalk down
yard and visually inspect for damaged equipment or missing/broken grounds.tailboard with
other crews in working in the same area. Maintain speed limits and follow roadways.
What insula ng mediums are used in EHV breakers?
SF6 gas, ultra-dry high pressure air, polymer, ceramics, air, epoxy, silicone
What does a WIKA gauge measure?
WIKA is a brand. Usually, it is measuring gas pressure.
, What is the minimum % of gas density that SRP allows in an EHV breaker?
98% on all new breakers,98% on Palo Verde Breakers, 97% on all other voltage class breakers
including older 500KV breakers.
Is SF6 gas harmful and or a hazardous material?
Yes, it displaces oxygen and can create a toxic substance when used to suppress an electric arc.
It is invisible, odorless, and tasteless.
Explain the difference between a live tank and a dead tank breaker.
A live Tank breaker has external energized tanks that are isolated from ground. These tanks
contain the interrup ng contacts, which are above ground poten al.
A dead tank breaker has their interrup ng contacts enclosed in tanks that are at ground
poten al.
What type of EHV breaker has a free standing C.T.?
A live tank breaker.
Preventa ve breaker maintenance consists of what?
Tailboard and be working under a grounded clearance. Power factor test, ductor/micro-ohm
test (the resistance of closed contacts, ming test ( opening and closing) , checking moisture,
purity and density of SF6 gas (and content of SO2 if any), pressure switch seHngs, service the
compressors (oil change and belt checks, pump mes), check heaters, mechanism travel
measurements, alarm checks ( low gas and low gas lock outs, motor trouble/fail) , and an
inspec on of the overall condi on of the breaker.
Name the different types of opera ng mechanisms and explain the safety hazards associated
with each.
Air Hazards include: pressurized containment vessel, air leaks are not visible, fiHngs, hoses,
regulators and air tools need to be rated for the pressure to be applied, beware of moving parts,
drain air pressure before performing maintenance.
Hydraulic hazards: pressurized containment vessel, containment vessel has a nitrogen pre-
charge pressure even a2er hydraulic pressure has been drained, hydraulic oil is flammable,
beware of moving parts, drain hydraulic pressure before performing maintenance.
Spring hazards: beware of moving parts, discharge spring pressure before performing
maintenance, spring can be charged in both open and closed breaker posi ons.
