Questions and Answers
What unit is the measure of electric shock intensity?
Current (Amperes)
What level of current will a person be unable to let go?
10 Milliamps
What level of current can be fatal if felt for more than 1 second?
100 Milliamps
PPE is required when working with what voltage?
Signup and view all the answers
What are the symptoms of electric shock?
Signup and view all the answers
If someone experiences electric shock, what action should be taken for loss of breathing?
Signup and view all the answers
What are the first two steps when someone is being electrocuted?
Signup and view all the answers
What is a flash protection boundary?
Signup and view all the answers
What is the purpose of equipment grounding?
Signup and view all the answers
What is an EMI Filter used for?
Signup and view all the answers
What are TVSS systems?
Signup and view all the answers
What are Arc Fault Detection Systems?
Signup and view all the answers
Work on energized systems above this voltage is prohibited unless approved by NAVSEA.
Signup and view all the answers
When may interlocks be 'cheated'?
Signup and view all the answers
Whose approval is required for work on energized electrical equipment over 30 volts?
Signup and view all the answers
What are some safety precautions when working on energized equipment?
Signup and view all the answers
What are STW Checks?
Signup and view all the answers
What safety checks must be completed during STW checks?
Signup and view all the answers
When do STW checks not need to be completed?
Signup and view all the answers
What is 'deranged equipment' now called?
Signup and view all the answers
For repair activity work conducted shipboard not IAW NSTM Chapter 300, a ___ between shipyards/repair activities and Ship's Force must be documented.
Signup and view all the answers
For naval applications, voltages greater than or equal to ___ are considered high voltage.
Signup and view all the answers
The resistance of a human body is about ___
Signup and view all the answers
When the skin is damp, the resistance of a human body is about ___
Signup and view all the answers
A situation where electrical current passes through air gaps between ungrounded conductors or between conductors and grounded components is called?
Signup and view all the answers
Another product of an arc flash is the incident energy, which is ___
Signup and view all the answers
Occurs when the severity of an arc or short circuit current causes destructive heating and explosive vaporization of both the surrounding air and the metal in the current path?
Signup and view all the answers
The unobstructed distance from exposed energized circuits within which unprotected skin could receive a second degree burn if an arc flash were to occur is known as?
Signup and view all the answers
Flash Protection Boundaries is abbreviated as?
Signup and view all the answers
The FPB distance aboard a ship for 450-volt circuits is ___
Signup and view all the answers
The FPB distance aboard a ship for 4160-volt circuits is ___
Signup and view all the answers
The FPB distance aboard a ship for 13.8K volt circuits is ___
Signup and view all the answers
An FPB of 4 feet is applicable to circuits with rated voltages between ___
Signup and view all the answers
An FPB of 11 feet is applicable to circuits with rated voltages between ___
Signup and view all the answers
An FPB of 13 feet is applicable for voltages ___
Signup and view all the answers
Study Notes
Electric Shock and Current
- Electric shock intensity is measured in Amperes (current).
- 10 milliamps is the current level at which a person cannot release their grip.
- A current of 100 milliamps can be fatal if sustained for more than one second.
Personal Protective Equipment (PPE)
- PPE is mandatory when working with voltages of 30 volts and above.
Symptoms and Emergency Actions
- Symptoms of electric shock include pale or bluish skin, weak pulse or breathing, and body stiffness.
- Perform CPR if a person loses breathing due to electric shock.
- First two steps during an electrocution incident: shut off power (or remove the victim using dry, non-conductive materials) and administer first aid.
Safety and Protection Measures
- Flash protection boundary (FPB) is defined as the distance from an energized circuit that could cause a second-degree burn from an arc flash.
- Equipment grounding ensures a low-resistance path to reduce dangers from electrical failures.
Electrical Systems and Protection Devices
- EMI Filters minimize interference in shipboard electrical and electronic systems.
- Transient Voltage Surge Suppression (TVSS) systems absorb and clamp voltage spikes on the main AC bus.
- Arc Fault Detection Systems are installed on switchboards to detect arc flashes and minimize damage.
Voltage Regulations and Approvals
- Work on energized systems is prohibited above 1000 volts unless approved by NAVSEA.
- Commands for work on energized electrical equipment over 30 volts require Commanding Officer approval.
Safe Practices in Energized Conditions
- Safety precautions include removing all metal, wearing rubber gloves, using one hand while working, and ensuring someone CPR qualified is present.
- Safe-to-Work (STW) checks are necessary after prolonged inactivity or changes in boundaries, including verifying danger tags, work authorization forms (WAFs), and voltage levels.
- STW checks are unnecessary when working on systems under 30 volts.
Equipment and Voltage Classifications
- "Deranged equipment" is now referred to as damaged equipment.
- For naval applications, voltages equal to or greater than 1000 volts are categorized as high voltage.
Human Body Resistance
- The average resistance of a human body is around 500 ohms, which decreases to 300 ohms when the skin is damp.
Arc Phenomena
- An arc flash occurs when current passes through air gaps between ungrounded conductors or between conductors and ground.
- Incident energy from an arc flash is classified as radiant energy.
- An arc blast results from severe heating due to high current, leading to explosive vaporization of air and surrounding metal.
Flash Protection Boundary (FPB) Details
- FPB defines the distance where unprotected skin could suffer burns from an arc flash.
- FPB ranges for energized circuits aboard ships:
- 4 feet for circuits rated between 30-1000 volts.
- 11 feet for circuits rated between 1000-5000 volts.
- 13 feet for voltages exceeding 5000 volts.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers essential knowledge on electric shock intensity, symptoms, and emergency responses. It also highlights the importance of Personal Protective Equipment (PPE) and safety measures when handling electricity. Prepare to learn and assess your understanding of electrical safety protocols.