NFPA70 Study Guide Questions with Correct Answers

NFPA70 Study Guide Questions with Correct Answers What is an Arc Flash? - Answer-A short circuit that jumps through the air from one exposed conductor to another. What makes an Ar Flash dangerous? - Answer-Temperatures of up to 35k' F, shrapnel, molten metal, chocks, shockwave (2k lbs/foot^2), soud (140 dB), burn injuries. Hazard/Risk Category 1 contains PPE requirements. What are they? - Answer-hardhat, safety glasses, hearing protection, heavy duty leather gloves, leather work shoes. What proper electrical PPE protect you from? - Answer-burns, electrical shock and small shrapnel. What is PPE? - Answer-Personal Protective Equipment If you are qualified to work on low-voltage equipment, what is the cut-off point where you are not allowed to perform electrical tasks at higher voltages? - Answer-50 - 600V What is the most important part of creating an electrically safe work condition - Answer- Test for Voltage Once an electrically safe work condition is created, shock and arc flash protection are no longer necessary. (T/F) - Answer-True The Arc Flash Protection Boundary is the distance from an arc source where an unprotected worker will receive first-degree burns. (T/F). - Answer-False When dressing in layers for arc flash protection, non-FR material can be counted toward your total level of protection. (T/F). - Answer-False When dressing in layers for arc flash protection, non-FR material can be counted toward your total level of protection. (T/F). - Answer-False live work. - Answer-Prohibited Approach Boundary For energized circuits, escorted unqualified persons are allowed within which Hazard Protection Approach Boundaries? - Answer-Limited Approach Boundary If an electrical circuit that normally operates above 50 volts has been de-energized but not tested to verify that the circuit is in an electrically safe work condition, which of the following apply? - Answer-Requirements associated with flash protection boundary must be followed. Only qualified persons shall perform tasks such as testing and voltage measuring within the limited approach boundary of energized electrical conductors operating at 50 volts or more or where an electrical hazard exists. (T/F). - Answer-True What is the time in which a GFCI is required to open a circuit in the event of a fault? - Answer-1/40th of a second Which Hazard Risk Category requires clothing that provides a minimum of 25 calories/cm^2 arc-rated protection? - Answer-Category III What electrial Hazards are NOT covered in NFPA 70E? - Answer-Lightning strikes Hazard Risk Category Two requires a minimum of a 40 cal/cm^2 Arc Rated Clothing. (T/F) - Answer-False For work under Hazard/Risk Categories 1, 2, 3 and 4, which of the following PPE is always required? - Answer-Hardhat Electric hock Hazard, Extreme Temperatures molten metal debris, intense light, sound waves and pressure are some of the reasons why this type of analysis is done. - Answer-Flash Hazard or Arc Flash Hazard. The National Electrical Code is generally considered an electrical installation document and protects employees under normal circumstances is referred to as: - Answer-NFP70 The National Protection Association developed a standard addressing electrical safe work practices in 1979, referred to as? - Answer-Best Practice What leel of fault current is required to open a GFCI contact? - Answer-GmA What is the safest way to work on electrical equipment? - Answer-de-energize test, verify live/dead/live Hazard Risk Category Zero is the only category where only untreated natural fiber clothing that is not arc-rated is allowed. (T/F). - Answer-True An Arc flash boundary includes the following EXCEPT: - Answer-Qualified Approach A qualified electrial person shall: - Answer-Be trained and knowledgeable of the operation of equipment and trained to recognize and avoid the electrical hazards that might be present to the equipment or work method. An unqualified person shall be trained in and be familiar with, any electrical safety related practices necessary for their safety. (T/F). - Answer-True The temperature of an Arc flash at the source can reach. - Answer-35,000' F Proper PPE selection for the Hazard Risk Category a worker will: - Answer-Prevent the onset of second degree burns half of the time for the worker.