Questions and Answers
The use of Chapter 9, Table 1 for conduit fill allows the use of which additional tables in the notes to Table 1?
Tables 4, 5, 5A, and 8
Fill requirements for rigid metal conduit are addressed in Section 344.22. This section refers the user to Chapter 9, Table 1.
True
Tables 11(A) and 11(B) are designed as information when dealing with which systems?
Class 2 and Class 3 AC and DC wiring
Tables 12(A) and 12(B) are designed as information when dealing with what?
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The information in the Annexes of the NEC is enforceable by AHJ.
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The tables in Annex C are to be used only when?
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The percentage to use for conduit fill when installing one cable assembly with five conductors in the cable assembly is?
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When calculating the number of 10 AWG conductors that may be installed in a raceway, when the calculation results in a decimal of what or greater, the calculated number can be rounded up to the next whole number?
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When installing six conductors in a nipple between boxes, what fill shall be permitted to be used?
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How many 10 AWG THHN conductors may be installed in a one-inch EMT conduit?
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What is 60% of the cross-sectional area of a one-inch EMT conduit?
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What is the cross-sectional area of a 10 AWG THHN stranded copper conductor?
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How many 10 AWG THHN copper conductors may be installed in a one-inch EMT nipple 12 inches long?
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What is the minimum bending radius of one-inch EMT conduit using a hand bender?
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What UL standard number covers ground-fault circuit interrupters?
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Where all of the conductors are the same size, which table in Annex C covers intermediate metal conduit?
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Using the forward reach requirements, if a switch is installed on the wall above a countertop that protrudes 22 inches from the wall, what is the maximum height allowed for the switch according to the 2010 ADA standards?
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In the absence of manufacturer's torque recommendations, what may be used?
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For a critical operations power system using 8,760 hours for a typical year, a system with an availability of 0.9999 will have a maximum downtime of what?
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What is the maximum number of 12 AWG THHN conductors that can be installed in 3/8-inch FMC, where the fitting is on the outside of the conduit? Include an equipment grounding conductor.
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When installing four conductors in a rigid metal raceway with a sealing fitting such as those found in a Class 1, Division 1 location, what percentage of conduit fill is permitted?
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Study Notes
NEC Chapter 9: Tables and Informative Annexes Overview
- Chapter 9, Table 1 for conduit fill permits the use of additional tables including Tables 4, 5, 5A, and 8.
- Rigid metal conduit fill requirements are specified in Section 344.22, linking to Chapter 9, Table 1 for enforcement.
- Tables 11(A) and 11(B) address Class 2 and Class 3 AC and DC wiring systems.
- Tables 12(A) and 12(B) provide information related to PLFA (Power-Limited Fire Alarm).
Annexes and Non-Enforceability
- Information in NEC Annexes is not enforceable by the Authority Having Jurisdiction (AHJ).
- Annex C tables are applicable only when all conductors in the raceway are of the same size.
Conduit Fill Calculations
- For one cable assembly with five conductors, the conduit fill percentage is 53%.
- When calculating 10 AWG conductor capacity in a raceway, if results yield a decimal of 0.8 or greater, round up to the next whole number.
- For a nipple between boxes containing six conductors, standard fill regulations are not applicable.
Conductor and Conduit Specifications
- A one-inch EMT conduit accommodates a maximum of 16 10 AWG THHN conductors.
- 60% of the cross-sectional area for a one-inch EMT conduit equals 0.519 in².
- The cross-sectional area of a 10 AWG THHN stranded copper conductor measures 0.0211 in².
- In a one-inch EMT nipple measuring 12 inches, 24 10 AWG THHN copper conductors can be installed.
Bending Radius and Standards
- The minimum bending radius for a one-inch EMT conduit with a hand bender is 5.75 inches.
- Ground-fault circuit interrupters fall under UL standard number UL 943.
Additional Tables in Annex C
- Intermediate metal conduit specifications when all conductors are the same size are detailed in Table C.4.
Height and Torque Standards
- According to 2010 ADA standards, a switch above a countertop extending 22 inches from the wall cannot exceed a height of 44 inches.
- In the absence of manufacturer's torque recommendations, refer to Annex I for guidance.
System Availability and Installation Limits
- For critical operations power systems using 8,760 hours in a year, a system with 0.9999 availability experiences no permissible downtime.
- A maximum of 3 12 AWG THHN conductors can be installed in 3/8-inch FMC when an equipment grounding conductor is included.
- In rigid metal raceways with sealing fittings in Class 1, Division 1 locations, 25% conduit fill is allowed for four conductors.
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Description
Test your knowledge of NEC Chapter 9, which focuses on tables related to conduit fill and other relevant information. This quiz covers definitions and concepts related to Tables 1, 4, 5, 5A, and 8 in the chapter. Perfect for electrical professionals seeking to reinforce their understanding.
