What Do You Know About Wire And Cables?
Wire is a single, usually cylindrical, flexible strand or rod of metal – used to bear mechanical loads of electricity and telecommunication signals. Cable is commonly known as several wires laid into a helix. What do you know about the two?
- 1.
When using electrical metal tubing, the maximum distance between pull points (boxes) is
- A.
100 feet
- B.
50 feet
- C.
The length of your snake.
- D.
Undefined. There is no maximum distance specified in the code.
Correct Answer
D. Undefined. There is no maximum distance specified in the code.Explanation
NFPA 70, 358.26Rate this question:
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- 2.
Non-listed wire may be used anywhere other than a plenum.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The correct answer is False because non-listed wire should not be used anywhere, including plenum areas. Plenum areas are spaces used for air circulation in buildings, such as the area above a drop ceiling or below a raised floor. These areas are required to use plenum-rated cables, which are specifically designed to have low smoke and flame spread in case of a fire. Using non-listed wire in a plenum area can pose a safety hazard as it may contribute to the spread of fire and toxic fumes. Therefore, it is incorrect to say that non-listed wire can be used anywhere other than a plenum.Rate this question:
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- 3.
Cables controlled by or containing wires or fiber-optic strands of private signaling organizations
- A.
Never be used on a fire alarm system.
- B.
Shall be permitted to be used for fire alarm purposes only by permission of the authority having jurisdiction.
- C.
Shall not be permitted to be used for fire alarm purposes unless approved by an electrical engineer qualified to test such cables.
- D.
Must be terminated by a certified cable technician certified by ANSI.
Correct Answer
B. Shall be permitted to be used for fire alarm purposes only by permission of the authority having jurisdiction.Explanation
NFPA 72, 2010 edition, section 27.7.1.2.4.2Rate this question:
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- 4.
Wires must be protected from physical damage anytime they are
- A.
Within 10 feet of the floor.
- B.
Within 10 feet of the ceiling.
- C.
Within 7 feet of the floor.
- D.
Exposed.
Correct Answer
C. Within 7 feet of the floor.Explanation
Wires must be protected from physical damage anytime they are within 7 feet of the floor. This is because wires that are closer to the floor are more susceptible to damage from foot traffic, furniture, or other objects that may come in contact with them. By providing protection for wires within 7 feet of the floor, the risk of damage and potential hazards such as electrical shocks or short circuits can be minimized.Rate this question:
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- 5.
When used in aerial construction, fire alarm wires and cables shall be located
- A.
Below all other wires.
- B.
Above all other wires.
- C.
In between cables used for telecommunication and power cables.
- D.
Under all other wires except communications wires.
Correct Answer
D. Under all other wires except communications wires.Explanation
NPFA 72, 2010 edition, section 27.7.1.4.1Rate this question:
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- 6.
The most common type of tubing used in the security industry for raceways is
- A.
FMC
- B.
HDPE
- C.
EMT
- D.
RNC
Correct Answer
C. EMTExplanation
EMT stands for Electrical Metallic Tubing, which is the most common type of tubing used in the security industry for raceways. EMT is made of steel and is highly durable, providing excellent protection for electrical wires and cables. It is also easy to install and is widely available, making it a popular choice for security installations. HDPE, RNC, and FMC are not commonly used in the security industry for raceways, making EMT the correct answer.Rate this question:
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- 7.
Which of the following is not a test used when approving Class 2 low-voltage transformers?
- A.
Circuit Secondary Voltage Test
- B.
Testing for compliance with CP-01 standards when packaged as a complete assembly
- C.
Output Current and Power Test
- D.
Rated Output Heating Test
Correct Answer
B. Testing for compliance with CP-01 standards when packaged as a complete assemblyExplanation
The question asks for a test that is not used when approving Class 2 low-voltage transformers. The options include Circuit Secondary Voltage Test, Testing for compliance with CP-01 standards when packaged as a complete assembly, Output Current and Power Test, and Rated Output Heating Test. The correct answer is Testing for compliance with CP-01 standards when packaged as a complete assembly. This means that this test is not used when approving Class 2 low-voltage transformers.Rate this question:
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- 8.
Cables or raceways that run parallel to framing members or furring strips must be protected where they are likely to be penetrated by nails or screws by installing the wiring method so it isn’t less than ______ from the nearest edge of the framing member or furring strips.
- A.
3/4 inch
- B.
1/2 inch
- C.
1 1/4 inch
- D.
1 inch
Correct Answer
C. 1 1/4 inchExplanation
Cables or raceways that run parallel to framing members or furring strips must be protected where they are likely to be penetrated by nails or screws by installing the wiring method so it isn't less than 1 1/4 inch from the nearest edge of the framing member or furring strips. This distance ensures that the cables or raceways are adequately protected and reduces the risk of damage from nails or screws.Rate this question:
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- 9.
Electrical metallic tubing must be securely fastened within _____ of every box, cabinet, or termination fitting, and at intervals not exceeding ______.
- A.
12 inches / 5 feet
- B.
3 feet / 10 feet
- C.
18 inches / 10 feet
- D.
6 inches / 10 feet
Correct Answer
B. 3 feet / 10 feetExplanation
Electrical metallic tubing must be securely fastened within 3 feet of every box, cabinet, or termination fitting, and at intervals not exceeding 10 feet. This ensures that the tubing is properly supported and reduces the risk of damage or disconnection. By fastening the tubing at these intervals, it maintains stability and prevents it from sagging or becoming loose. This spacing also allows for easy access and maintenance if needed.Rate this question:
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- 10.
If the edge of the framing member or furring strip is less than 1¼ inch away, a _____-thick steel plate of sufficient length and width must be installed to protect the wiring method from screws and nails.
- A.
1/8 inch
- B.
1/16 inch
- C.
1/4 inch
- D.
1/2 inch
Correct Answer
B. 1/16 inchExplanation
If the edge of the framing member or furring strip is less than 1¼ inch away, a 1/16 inch thick steel plate of sufficient length and width must be installed to protect the wiring method from screws and nails. This means that if the distance between the framing member or furring strip and the wiring method is less than 1¼ inch, a 1/16 inch thick steel plate should be used as a protective barrier to prevent damage to the wiring from screws and nails.Rate this question:
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- 11.
A box must be installed at each splice of termination point, except for
- A.
Communications, signal, and control conductors.
- B.
Line voltage connections.
- C.
Class 1 connections.
- D.
None. A box is always required for a splice.
Correct Answer
A. Communications, signal, and control conductors.Explanation
NFPA 70, 300.15Rate this question:
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- 12.
Which of the following wiring methods are permitted to be used in a ceiling area designated for environmental air?
- A.
EMT
- B.
Flexible metal conduit
- C.
Rigid metal conduit
- D.
Any of the above
- E.
None of the above
Correct Answer
D. Any of the aboveExplanation
Any of the above wiring methods are permitted to be used in a ceiling area designated for environmental air. This means that EMT, flexible metal conduit, and rigid metal conduit can all be used in this specific area.Rate this question:
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