How to Look

at a House


A blog with answers
to your questions about
HOME INSPECTION
and HOME MAINTENANCE

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We want you to be an informed homebuyer, and each blog post is a question that we have answered for our friends and customers over the years. Hope they help you make a good choice for your next home.

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Watt - Volts x Amps = Watts. It is a “unit of power,” and can also be described as a measure of the amount of energy produced. A flow of 3 amps from a typical house 120-volt  receptacle outlet equals 360 watts. Ohm - A “unit of electrical resistance” to current flow. The heating elements in a toaster, for example, have high electrical resistance that creates heat.

Short Circuit - An unintended connection between parts of a circuit. A short circuit typically, but not always, trips a circuit breaker, and a short at a receptacle outlet leaves black burn marks on the cover plate from the surge of electricity.

Electrical Components

Bus - A metal strip inside a panel that serves as a common connection for multiple circuit wires. A panel typically has both a neutral and ground bus, or a single bus for both.

Bus Bar - A metal strip inside a panel used to connect circuit breakers. Cable - A cluster of wires encased in a flexible sheathing. Initials identify the type of cable, such as NM (Non-Metallic) or UF (Underground Feeder).

Conductors - There are three types:

  1. 1)Ungrounded Conductors - The “hot”wires, usually black or red.

  2. 2)Grounded Conductors - The “neutral” wires, usually white.

  3. 3)Grounding Conductors - The “ground” wires, usually green or bare wires.

Dead Front - The plate the covers the front of an electric panel, with openings for the circuit breakers to protrude, enabling them them to be safety operated while protecting the live electrical connections behind it from contract. Called a “dead” front because it is isolated from any voltage in the panel.

Disconnect - A device that cuts off the current to an appliance or circuit. It can be a switch, circuit breaker, or cord that can be unplugged from a receptacle.

Electric Panel - The cabinet with components that distribute electricity around the home. The first panel after the electric meter is called the service panel and the ones after that are subpanels. “Main panel” is a slang term sometimes used to describe the service panel.

Grounding Electrode - A conductive object makes a connection to earth from the electrical system. It is typically a ground rod, but can also be underground metal piping or the reinforcing steel in a foundation footing.

Knockout - Perforated circular tabs in the walls of an electric panel that can be easily broken loose to create a hole for bringing wiring into panel.

Luminaire - A term that has replaced what was formerly called a “light fixture” in building codes.

Receptacle Outlet - A connection device that receives a plug and cord. A receptacle that have two plugs connected to it is a duplex receptacle.

Service Drop - The overhead wires that run from the utility transformer to the house.

Service  Lateral - Underground wires running from theutility transformer to the house.

Service Mast - The pipe that extends above the roof to which the service drop wires are connected. It is topped with a weatherhead to keep water out.

Terminal - A lug or screws that secure wires to breakers, bus bars, and neutral/ground bus.

Twistout - Perforated metal plate in a panel dead front that is removed (twisted out) to allow a circuit breaker handle to protrude through the dead front.


Blog Posts About Typical Electrical Defects

  1. What are the most common homeowner wiring mistakes?

  2. Can old electrical wiring go bad inside a wall?

  3. What are the most common problems with electrical outlets?

  4. My circuit breaker won’t reset. What’s wrong?

  5. What is reversed polarity at an outlet/receptacle? Why is it dangerous?

  6. Why is a fuse box an insurance problem for homebuyers?

  7. Why is undersize wiring in a house dangerous?

  8. What is an open electrical splice?


While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© McGarry and Madsen Inspection


More blogs about electrical service and distribution:

  1. How come my generator hookup got tagged as defective by the home inspector?

  2. Is the electric panel big enough for this house?

  3. How do the new tamper-resistant electric receptacles work?

  4. The electric panel is marked “Trilliant” and it’s all grey plastic. Is it alright?

  5. Why do you pay so much attention to electrical safety?

  6. What is the life expectancy of a circuit breaker?

  7. How dangerous is old electrical wiring?

  8. What is the right electric wire size for a home?

  9. Why does the electric company want my house electric system inspected before turning the power back on?

  10. What is a double tap at a circuit breaker?

  11. Why does that wall plug have push-buttons in the middle?

  12. Does this place have one of those “bad” electric panels I’ve heard about?

  13. My bathroom electric receptacle/outlet is dead, and there is no tripped breaker in the electric panel. What’s wrong?

  14. What is the switch on the wall with only two pushbuttons for?

  15. What are those strange looking wall switches in houses from the 1950s and 1960s?

  16. What is a lock device on a circuit breaker for?

  17. Can multiple neutral or ground wires be secured under the same terminal in an electric panel?

  18. Why are Zinsco and Sylvania-Zinsco electric panels a problem?

  19. Can wiremold be used at an exterior location?

  20. What is the life expectancy of electrical wiring in a house?

  21. How can adding wood paneling or a wainscot create an electrical safety hazard?

  22. What are the most common electrical defects found in a home inspection?

  23. Why is an old fuse panel dangerous?

  24. What does it mean when a wire is “overstripped” at a circuit breaker?

  25. What is the difference between “grounded” and “grounding” electrical conductors?

  26. What is the difference between a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?

  27. How can I tell if a receptacle/outlet is tamper resistant?

  28. What is a Dual Function Circuit Interrupter (DFCI)?

  29. Will a GFCI receptacle that is not grounded still function properly?

  30. Does a home inspector remove the electric panel cover plate and examine the inside of the panel?

  31. Can an electric panel be located over stairs?

  32. What are the code requirements for NM-cable (nonmetallic-sheathed cable or Romex®) in an attic?

  33. How do I trace and identify each circuit breaker in my electric panel to make a circuit directory?

  34. Why are extension cords dangerous?

  35. What problems does having too many electrical outlets on a single circuit cause?

  36. How can I find out the size of the electric service to a house?

  37. What happens when you press the “TEST” button on a circuit breaker in an electric panel?

  38. How many electric receptacles (outlets) are required in a hallway?

  39. Why does painting an electric receptacle (outlet) make it unsafe?

  40. Why are old electrical systems not always “grandfathered” as acceptable by home inspectors?

  41. Why do the lights dim when the air conditioner turns on?

  42. Where are GFCI receptacle outlets required?

  43. When were GFCI receptacle outlets first required?

  44. What is the height requirement for an electric receptacle outlet?

  45. Why are some electric receptacle outlets upside down (ground slot up) in a house?

  46. What is a “backstab” receptacle outlet?

  47. What electrical hazards does a Ground Fault Circuit interrupter NOT protect against?

  48. What does “listed” and “labeled” mean for an electrical component?

  49. What does it mean when I find buried yellow "CAUTION" tape when digging a hole in the yard?

  50. Can a washer or dryer be located in front of an electric panel?

  51. How far away should a sink be from an electric panel?

  52. What are the requirements for NM-cables entering an electric panel box?

  53. How can I tell if the electrical service is 3 phase or single phase?

  54. What is the minimum clearance of overhead electric service drop wires above a house roof?

  55. What is the building code requirement for receptacle outlets at stairs and stair landings?

  56. Can a home surge protector be installed loose in the bottom of an electric panel box?

  57. Can a bare bulb “lampholder” light fixture be installed outdoors?

  58. Can you add circuit breakers by different manufacturers to an electric panel if they fit?

  59. When did arc fault circuit interrupter (AFCI) breakers first become required?

  60. What is the difference between an electrical receptacle, an outlet, and a plug?

  61. Should I buy a house near a high-voltage power line?

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