National Home Inspector Exam Prep Podcast
The Complete National Home Inspector Training Manual—In Audio Form
Welcome to National Home Inspector Exam Prep Podcast—the most comprehensive audio course for aspiring home inspectors preparing for the National Home Inspector Exam.
Your Complete Exam Preparation Resource
This is a complete professional training program based on the National Home Inspection Training Manual, transformed into detailed audio lessons you can study anywhere, anytime. Whether you're commuting, at the gym, or reviewing before bed, master the entire home inspection curriculum.
Complete 16-Discipline Coverage:
This training program covers ALL major areas tested on the National Home Inspector Exam:
📋 Analysis & Reporting - Professional report writing and communication
❄️ Cooling Systems - Air conditioning, heat pumps, and distribution
⚡ Electrical Systems - Service equipment, panels, circuits, wiring, safety devices
🏠 Exterior Components - Siding, trim, doors, windows, finishes
🔥 Fireplaces & Chimneys - Masonry and factory-built systems, venting, safety
📖 Complete Glossary - Essential professional terminology
🔥 Heating Systems - Furnaces, boilers, distribution, controls
🌬️ Insulation & Ventilation - Attic ventilation, insulation types, energy efficiency
🍳 Kitchen Appliances - Ranges, ovens, dishwashers, disposals, built-ins
🚰 Plumbing Systems - Supply, drainage, water heaters, fixtures
👔 Professional Responsibilities - Ethics, standards of practice, business practices
🏚️ Roof Components - Coverings, flashings, drainage, structural elements
🌳 Site Conditions - Grading, drainage, driveways, landscaping
🏗️ Structural Components - Foundations, framing, load paths, structural defects
🪟 House Interior - Walls, ceilings, floors, stairs, doors, windows
200+ Detailed Episodes
Each episode provides in-depth coverage of specific topics within each discipline. Episodes are designed to be studied in sequence, building your knowledge systematically from fundamentals to advanced inspection techniques.
Who This Is For:
✅ New home inspectors studying for the National Home Inspector Exam
✅ Career changers entering the home inspection profession
✅ Real estate professionals expanding technical knowledge
✅ Anyone preparing for state licensing exams
✅ Practicing inspectors seeking continuing education
Why This Training Works:
🎯 Exam-Focused - Aligned with National Home Inspector Exam requirements
🎯 Field-Tested - Based on real inspection scenarios and common defects
🎯 Code-Referenced - Current IRC standards and industry best practices
🎯 Comprehensive - Complete coverage, not just highlights
🎯 Audio Learning - Study while driving, working out, or multitasking
🎯 Sequential Structure - Logical progression builds expertise systematically
Study Approach:
For best results, listen to episodes in numerical order within each discipline. Take notes, pause to review complex topics, and re-listen to challenging sections. This is professional training designed for exam success.
Beyond the Podcast:
This podcast is part of our complete National Home Inspector Training program. For comprehensive training including visual materials, practice exams, hands-on demonstrations, and certification support, visit [YOUR WEBSITE URL].
National Home Inspector Exam Prep Podcast
08 - Old Wiring Methods: Knob & Tube, Cloth-Covered, Aluminum
Knob and Tube Wiring (1900s-1930s)
Named for ceramic knobs (support conductors) and ceramic tubes (protect conductors through framing). Most popular early 1900s to 1930s. Still may be installed as extension of existing systems.
Correct Installation Standards:
- ≥1" distance between wires and objects (walls, floors, framing)
- ≥3" distance between wires
- ≤6" between knobs and wire splice
- ≤4½ feet between knobs in wire runs
- Wires on sides of joists/rafters/studs (not on top)
- Tubes where wires penetrate framing
- Taps between knob-tube wires: May occur outside boxes (soldered/taped)
- Taps to other wiring: Must be in covered box with appropriate protection
Major Problems:
- Covering with thermal insulation NOT allowed (NEC Article 394.12)
- Contact with metal (pipes, ducts, foil) is major deficiency
- At end of service life
- Usually no EGC (safety issue)
- 15-amp circuits (may be overloaded)
- Potential asbestos in insulation
- Insurance/mortgage underwriting issues
Cloth-Covered NM (1940s-1950s)
Cotton or rayon sheathing (derogatory nickname: "rag wire"). Found late 1920s through 1960s. PVC sheathing replaced cloth in 1960s.
Problems:
- Cloth sheathing and insulation deteriorate/become brittle with age
- Vermin chew on cloth
- No EGC (most installations)
- Insurance underwriting issues (some companies)
Tin-Coated Copper Wire (1940s-1950s)
Most popular 1940s-1950s. Looks like solid-conductor aluminum but check: cut wire shows copper, cloth insulation (not plastic).
Solid-Conductor Aluminum Wiring (1964-1980)
Manufactured 1964-1980 in #8-12 AWG NM cable for residential use. Copper became expensive; aluminum seemed like good alternative. Problems emerged quickly.
Why Aluminum Wire Failed:
- Galvanic reaction: Different metals in contact (with moisture) cause corrosion
- Oxidation: Aluminum "rusts," increasing resistance at connections
- Expansion/contraction: Different rates than copper and steel terminals
- Creep (cold flow): Wire becomes permanently distorted, smaller, brittle after expansion/contraction cycles
- Result: Loose connections, high resistance, arcing, heat, fires
New Aluminum Alloy (1972): More stable alloy introduced 1972, required 1981. By 1980, solid-conductor aluminum had bad reputation; manufacturers stopped producing it.
Distinguishing Aluminum Wire Types:
- Stranded aluminum (#8+ AWG): No problems with CO/ALR devices and CU/AL breakers. Used for large appliances, service entrance, feeders. Anti-oxidant paste highly recommended.
- Copper-clad aluminum (1970s): Uncommon. Looks like copper except aluminum visible at cuts. No reported problems. Rated as aluminum for ampacity.
- Solid-conductor aluminum (#8-12 AWG, 1964-1973): PROBLEMATIC. Especially old technology (pre-1972 alloy).
Typical Repair Solutions:
- Rewire entire house with copper (safest, expensive, disruptive)
- COPALUM connectors (cold-weld copper to aluminum, expensive ~$60/outlet, requires special tools/training, CPSC-recommended)
- AlumiConn connectors (less expensive, sold to public, requires proper installation)
- Replace devices with CO/ALR (helps post-1972 wire, doesn't address creep in old wire, doesn't address light outlets)
IRC/
For complete training with visual materials, practice exams, and certification support, visit nhiexamprep.com
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