How to Look

at a House

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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.

   Because an appliance switch is typically placed on the incoming hot wire side when it is wired correctly, everything past the switch is dead until turned on. If the wiring is backwards, the internal components of an appliance are electrified up to the point of the switch at the back end. No current is flowing, but it allows the possibility of electrical shock if someone inadvertently completes a circuit to ground with their body. Two examples would be poking inside a toaster with a knife to loosen a stuck piece of bread or touching the shell of a lamp socket—both of which could possibly shock you if the polarity of the wiring is reversed.

    Correct polarity can be defeated if the outlet itself is wired backwards, which is a safety defect we check for at a random sampling of wall outlets during a home inspection. Some appliance manufacturers overcome this potential problem by using a double-pole switch that disconnects the circuit at both the hot and neutral wires.

   Although polarized outlets and plugs were introduced in the 1880s, they were not popular at first and did not become standard until the mid-20th century. The earliest National Electric Code (NEC) that we can find that references polarized receptacles is the 1962 edition, which required outlets to be both grounding (3-prong) and polarized. We occasionally see an unpolarized outlet still in place in a vintage home with ungrounded 2-slot receptacles—like the battered, burnt, and ready-for-retirement one shown below.

    To read more about reversed polarity, see our blog post “What is reversed polarity at an outlet/receptacle? Why is it dangerous?”

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.
©2016 - McGarry and Madsen Inspection


More blog posts about electric service and distribution:

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

  2. How can I tell if the electric outlets are grounded?

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

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

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

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

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

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

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

  12. Is a bare bulb light in a closet alright?

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

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

  15. What is a “missing twistout” at an electric panel?

  16. Where are smoke alarms required to be located?

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

  18. How far apart should electric receptacle outlets be placed in a garage?

  19. Will the electric company remove branches rubbing against the overhead service lines to my home?

  20. What is the lock device on a circuit breaker for?

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

  22. Can wiremold be used at an exterior location?

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

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

  25. What is an open electrical splice?

  26. Why is an old fuse panel dangerous?

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

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

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

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

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

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

  33. What are the most common defects with over-the-range microwaves?

  34. Can an electric panel be located over stairs?

  35. Does a GFCI-receptacle that is not grounded still function properly?

  36. Is a house required to have outdoor electric outlets?

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

  38. How can I change a 240V circuit to a 120V circuit?

  39. Can old electric wiring go bad inside a wall?

  40. What could cause an extremely high electric bill?

  41. Why are extension cords dangerous?

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

  43. How many electrical receptacles (outlets) are required in a hallway?

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

  45. When was the three slot (grounding) outlet/receptacle first required?

  46. Why are old electric components not always “grandfathered” as acceptable by home inspectors?

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

  48. When were GFCI receptacle outlets first required?

  49. Where are GFCI receptacle outlets required?

  50. Why is bundled wiring in an electric panel a defect?

  51. Why are some electric receptacles/outlets upside down (ground slot up) in a house?

  52. Why is undersize electric wiring in a house dangerous?

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

  54. What is a “backstab” receptacle outlet?

  55. What electrical hazards does a Ground Fault Circuit Interrupter (GFCI) not protect against?

  56. What is the color code for NM cable (Romex®) sheathing?

  57. What are the right words for talking about a house electrical system?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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