Questions and Answers
Which insulation type is moisture resistant and suitable for wet conditions?
What is the temperature rating of RHW wiring insulation?
Which wiring type is not sunlight resistant?
What is a characteristic of THWN insulation?
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Which of the following conductors has a nylon jacket that aids in sliding through conduit?
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What is the maximum temperature rating for THW wiring insulation?
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Which wiring type is categorized under thermoset materials?
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What type of insulation is widely used in modern wiring?
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What feature differentiates XHHW-2 from other types of wiring insulation?
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Which insulation type is designed for moisture resistance?
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Which of the following materials is known for its extra heat resistance up to 1940F?
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What is required for all supports and fasteners in wet locations?
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What designation indicates a thermoplastic insulation that is heat resistant and rated for wet conditions?
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Which type of insulation was formerly used and has now become obsolete?
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How many quarter bends can be made in a single run between pull points?
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What is indicated by the designation 'N' in wiring designations?
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What is a necessary feature for wiring materials used in wet locations?
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Which of the following is true regarding hydraulic benders?
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Which insulation type provides protection against both heat and moisture?
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What insulation type is known for its use in old conductors?
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Which method helps in protecting wiring from overcurrent?
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Study Notes
Conductor Types and Insulation Ratings
- Not Moisture Resistant: Certain conduits are unsuitable for wet conditions, with no ratings for moisture resistance.
- Sunlight Resistance: Several types of conductors, including THW and THHN, do not withstand sunlight exposure.
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Temperature Ratings:
- THW-2: Thermoplastic, rated up to 194°F (900°C), not moisture or sunlight resistant.
- RHW: Thermoset insulation (rubber/synthetic), rated 167°F (750°C), moisture and heat resistant.
- THHN: Thermoplastic, rated 194°F (900°C), not moisture resistant.
- XHHW-2: Thermoset (cross-linked polymer), rated 194°F (900°C), suitable for wet and dry locations.
Insulation Materials and Designations
- Plastic Insulation: Most widely used for modern conductors, offering durability.
- Old Insulation: Cloth and rubber materials were common in older conductor designs.
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Common Designations:
- A: Glass fiber
- X: Cross-linked synthetic polymer (obsolete)
- FEP: Fluorinated ethylene propylene
- N: Nylon jacketed insulation
- R: Thermoset insulation (rubber/synthetic)
- THW: Thermoplastic with 167°F (750°C) rating.
- HH: Extra heat resistant up to 194°F (900°C).
Wiring Methods and Regulations
- Corrosion Resistance: All supports and hardware must use corrosion-resistant materials to ensure longevity.
- Bend Regulations: No more than four quarter bends (360° total) between pull points in conduit installations to maintain efficiency and effectiveness.
- Conduit Bending: 90° bends are commercially available, and hydraulic benders can be utilized on-site for installation adjustments.
Conductors for Wet Locations
- RHH: Thermoset insulation, 194°F (900°C) temperature rating, designed for wet conditions and provides extra heat resistance.
- Moisture and Heat Resistance: Key consideration for conductor choice in environments susceptible to varying temperatures and moisture levels.
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Description
Test your knowledge on different types of electrical wires and their insulation properties. This quiz covers various ratings including moisture resistance, temperature capabilities, and suitability for sunlight exposure. Perfect for electrical engineering students or professionals looking to refresh their knowledge.
