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Ask the Electrical Inspector

We received a bunch of good questions from readers regarding electrical codes in 2017 and passed them on to John Williamson, a bona fide electrical inspector. Here are his answers to your FAQ's.

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Garage door receptacles | Construction Pro Tips
Construction Pro Tips

Garage receptacles

Question: Is supplying receptacle outlets using 15-ampere branch circuits in house garages still permitted?

Answer: No, for new installations the code now requires at least one 20-ampere branch circuit to supply receptacle outlets in garages and detached garages with electric power. Although detached garages are not required to be supplied by electrical power, if they are powered they must comply with the code. Also, garage lighting cannot be supplied by the 20-ampere branch circuit. The garage lighting must be supplied by a general-purpose lighting branch circuit, but that branch circuit could be either 15 or 20-ampere. The idea here is that if a faulty tool blows a circuit, the occupant would not have to stumble around in the dark heading towards the panel.

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A diagram showing GFCI protection at sinks | Construction Pro Tips
Construction Pro Tips

Water source and GFCI

Question: I know that receptacles within 6-ft. of a sink need to be protected with a ground fault circuit interrupter (GFCI). But what if the appliance (fridge, microwave, etc.) that is plugged in to said receptacle is closer than 6-ft?

Answer: NEC 210.8 and NEC 210.8(A)(7) are very clear that the measurement is from the “top inside edge of the bowl of the sink” to the “receptacle”. The measurement is not to the appliance.

Image by the IAEI (International Association of Electrical Inspectors).

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A Sink | Construction Pro Tips
Construction Pro Tips

How to measure from sinks

Question: When it comes to sinks, receptacle outlets within 6-feet of the sink are required to be GFCI protected. Measuring from the outside edge of the sink is open to wide interpretation. Has this measurement process been clarified in the code?

Answer: The only thing that limits the styles and shapes of modern sinks is the designer’s imagination. Basing the measurement on the outside of the sink is not very clear. However, all sinks have one thing in common; they have a bowl that contains the water. The code now says that receptacle outlets installed within 6-feet of the “top inside edge of the bowl” must have GFCI protection. This change should help to eliminate any more arguments or misinterpretations.

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Garbage disposal under the sink | Construction Pro Tips
Construction Pro Tips

Garbage disposal outlets

Question: Don’t all garbage disposal outlets under sinks need GFCI protection? It’s definitely closer than 6-feet to the sink.

Answer: There is a new informational note in the code that provides clarity. Determining the distance from a receptacle to a water source is actually fairly simple. Just measure the distance of the shortest path to the receptacle outlet an appliance cord would follow without piercing a wall, a ceiling, or fixed barrier, or passing through a door, doorway or window. As always, be sure to check with your local electrical inspector. Despite this clarification in the code they may not be in agreement and they might still require GFCI protection for the garbage disposer receptacle outlet.

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Man sitting in a crawl space | Construction Pro Tips
Construction Pro Tips

GFCI protection in crawl spaces

  1. Q) As an electrician, I spend a lot of time in crawl spaces. Working in these confined areas always come with challenges and hazards, but bare or unguarded 120-volt incandescent light bulbs combined with damp dirt or concrete floors always make me uneasy because of the potential for an electrical shock. Doesn’t it make sense to require lighting in crawl spaces to be GFCI protected?
  1. A) It does, and it is. You’re not the only one who finds this situation unnerving. Due to a tragic fatality when a worker came into contact with a light bulb that had broken glass but an energized filament, the code now contains provisions that require GFCI protection for 120-volt lighting in crawl spaces that are at or below grade level.
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Electrical Code
Construction Pro Tips

NEC code questions

Question: My electricians have been studying the 2017 NEC changes in anticipation of the upcoming adoption of the new NEC in our state. One of my guys has a good idea for a change in the next edition of the code. How does he go about submitting a code proposal?

Answer: Public Input (formerly known as Proposals) for the 2020 NEC needs to be submitted no later than September 7, 2017. As the term implies, the NEC is an open, consensus process and accepts input and commentary from anyone. You can submit Public Input online at

Image supplied by

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Two Pronged Outlets
Construction Pro Tips

Two prong outlets in rentals

Question: I am a city rental inspector. A question has come up about two-prong outlets. Should we be making property owners replace two-prong outlets with three-prong GFCI outlets in bathrooms, kitchens, garages and outside if the home was built with two-prong outlets?

Answer: Except in very limited situations, the National Electrical Code (NEC) does not apply retroactively. There are many thousands of homes across the U.S. that contains one or more different wiring methods that were installed as far back as the 30’s and 40’s.

Existing electrical wiring is considered to be in compliance with the NEC that was in effect at the time of the original installation. That means existing electrical can remain if:

  • it’s in good condition and fully operational.
  • the can has not been subject to overloading or physical damage.
  • it is large enough to handle the electrical load.
  • the can is properly protected by overcurrent protection.

Rules for replacing

If a two-prong receptacle is going to be replaced, then it must comply with the following according to the NEC:

  • The basic rule is that receptacle outlets be replaced with a grounding-type receptacle outlet if an equipment grounding conductor is present in the receptacle box
  • If an equipment grounding conductor is not present in the receptacle box, there are options for using non-grounding-type replacement receptacles
  • A replacement receptacle HAS TO
    • have GFCI protection if it’s at a location that requires GFCI protection
    • have AFCI protection if it’s at a location that requires AFCI protection
    • be tamper-resistant (TR), unless the replacement receptacle is the non-grounding type (TR non-grounding-type receptacles are not available)
    • be weather-resistant (WR) if it’s at a location that requires WR receptacle outlets

As you can see, simply replacing a receptacle outlet can trigger several code requirements. And it can be even more complicated when the existing receptacle box from the 1930’s or 1940’s is too small to accept today’s larger receptacle devices. Very often the existing wall boxes must be replaced with larger boxes to accommodate the number of conductors and the new receptacle outlet. A simple two-hour project can quickly become an expensive two-day project.

Code authorities would always like to see everything brought up to current code, but that is not always a reasonable requirement. The State Building Code (which includes the electrical code) is a minimum standard. Enforcement of “the code” has to be reasonable and at the least possible cost, while still consistent with recognized standards of health and safety.

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Garage Framing
Construction Pro Tips

Electrical supply for a new garage

Question: Our organization builds around 120 new garages each year, and we would like to know if we are allowed to use the existing underground electrical supply if it has been determined by a licensed electrician to be in good shape. We do not want to add cost to the project and tear up our customer’s yard if we don’t have to.

Answer: For a new garage (where none previously existed) both the garage and the underground electrical supply to the garage need to comply with all provisions in the current NEC. There’s no debate on that one.

For a replacement garage (tear down and rebuild), the garage itself would be required to be wired in accordance with the current NEC. The existing underground electrical supply to the garage can be re-used if:

  • It’s in good working condition.
  • the supply is in good physical condition,
  • the supply is equipped with the proper overcurrent protection.
  • It’s sized correctly for the electrical load in the garage.

Generally, the existing underground electrical supply would not need to be brought up to code at this time. That being said, there could be circumstances (damage from rodents, water infiltration, etc.) that could warrant upgrading the underground electrical supply. A licensed electrical contractor is responsible for making that assessment.

Code authorities would always like to see everything brought up to current code, but that is not always a reasonable requirement. The State Building Code (which includes the electrical code) is a minimum standard. Enforcement of “the code” has to be reasonable and, at the very least, cost consistent with recognized standards of health and safety.

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Construction Pro Tips

Meet the inspector

John Williamson has been in the electrical industry for 40 years and is a licensed master electrician and certified building official. John has worked for the state of Minnesota for over 23 years and is the Chief Electrical Inspector. For the past 25 years John has also provided electrical code consultation to various book and magazine publishers.

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