I was replacing outlets in the basement and noticed that unfinished basements require them to be GFCI protected. While I did do this, I can't help but wonder: WHY?? I searched for the NEC definition of "unfinished basement" and I just don't see why the fact it's not "habitable" it needs GFCI. I can understand moisture areas like outlets near sinks, etc., but not this: my basement is very dry and whether the basement is finished or not does not affect the moisture content. Does the NEC explain this?

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    I admit the NEC handbook probably can't explain every reason why, but in my experience, knowing why provides intent and helps you "fill in the blanks" when the things aren't clear enough. I say this because lately I've read many discussions in multiple forums about how to interpret various parts of the handbook. Anyways, I was curious and thought it couldn't hurt to ask. If it IS just about moisture, then why not just say that (need GFCI when visible moisture is present)? :) Perhaps that's too subjective? Commented Feb 27, 2020 at 16:24

5 Answers 5


Even "dry" concrete contains considerable water, and is a relatively good conductor. So, it's a relatively good path to ground for a person touching it, increasing the odds of a lethal shock.

Generally, for something to make it into the electrical code, some number of people have probably died due to the lack of it before that happened.

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    Indeed, most building/fire/electrical codes are written in blood. Commented Feb 27, 2020 at 16:22
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    I like this answer. But, to "stir the pot": why not just say "GFCI protection is needed when there is a bare concrete floor"? Commented Feb 27, 2020 at 16:26
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    @AdirondackJim Because that would only target the one scenario. Ecnerwal's answer, while great, may not be entirely exhaustive.
    – ebwb
    Commented Feb 27, 2020 at 21:57
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    Understood--thanks. But, I wonder if the "unfinished basement" is too broad. Case in point: half the basement was a finished mancave (habitable, if I understand the term correctly). I'm now using it as a workshop, so it now needs GFCI protection. Room stayed the same, just a different use. Commented Feb 27, 2020 at 22:46
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    Years ago I saw a disturbing training video that used actual footage from 'the wild', capturing electrical shock incidents as they just happened to occur. One was of a person using a vacuum cleaner in their garage (with a concrete floor). Also "dry" concrete. Well, they died from an electrical shock when they touched the power switch of the vacuum. Dry concrete conducts well enough.
    – Jon Custer
    Commented Feb 28, 2020 at 15:11

You don't need GFCI receptacles anywhere. Nobody cares how you provision the GFCI protection. You are welcome to have one GFCI device and feed all the receptacles from the protected zone (LOAD) of that GFCI device. You should take the time to learn exactly how downline protection works, and then, put LOAD to good use! That will greatly reduce the cost of fitting GFCIs, since you then only need 1 per circuit.

It's really a statistical numbers game with the NFPA. They are looking at accident statistics and where accidents happen. It's not just the access to moisture-containing concrete and brick; it's also that the devices used in basements tend to be more risky equipment.

NFPA is now requiring GFCI and/or AFCI on pretty much every circuit, but the requirement for unfinished basements came in shortly after kitchens and bathrooms, i.e. high on their priority list. So it's pretty apparent this has been a problem area according to the statistics.

One thing you should do, if you have a freezer, refrigerator, fire alarm, radon system or other safety critical appliance, is talk to your AHJ (inspector) about a variance to exclude that appliance from GFCI. For pretty much all those systems, GFCI is completely useless because e.g. a refrigerator is grounded other ways, fire alarms and radon systems are hardwired and don't create particular shock risks, etc. The inspector will typically want to see a single, solitary receptacle (1-socket instead of 2-socket) and want it labeled "Refrigerator only". I for one prefer to put a regular 2-socket receptacle right next to it that is GFCI protected, so that no one is tempted to stick a 3-way splitter there or something.

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    Using a single GFIC outlet with non-GFIC outlets downstream from it does you save you money. The trade off is that when the outlet trips you don't know at which of those outlets the issue really is. With individual GFIC outlets there is no doubt. Personally, I spend a few more dollars up front to save possible annoyance later.
    – user689
    Commented Feb 27, 2020 at 12:52
  • Having a refrigerator share a GFCI with other devices would be bad, but if it's alone on a GFCI, what would cause it to trip in the absence of an insulation failure, flood, or other hazardous condition?
    – supercat
    Commented Feb 28, 2020 at 18:12
  • @supercat fridges have constant problems with tripping GFCIs. Even new ones. They shouldn't in theory, but they do. Commented Feb 28, 2020 at 20:03
  • I believe this answer is good because it works from (likely) evidence about the NEC process to come to its conclusion. (The suggestions about ways to be flexible and still safe with the rules are also good.)
    – X Goodrich
    Commented Feb 28, 2020 at 22:16
  • Y'all can look up the code and wonder why to your heart's discontent in the link below. If we're going to talk about GFCIs, then the discussion is Where should I NOT use a GFCI or AFCI? - basically nowhere can you not except those exceptions, the important one being the fridge, +1.
    – Mazura
    Commented Feb 29, 2020 at 0:54

Some basements are prone to flooding even if yours isn't. Plumbing is often run through basements which further increases the risk of a flood. If the outlets end up under water this isn't a good thing since water and electricity don't mix.

In this case, it's easier to apply a blanket rule to all basements in all areas than it is to regulate individual basements. Then people want to sue you because THEY did something stupid. It's better to be safe than sorry.


Partly because some unfinished basements have water containment risks, and the code is written to not create work for inspectors arguing the risk for each individual installation.

A Code-Making Panel document I saw a few of years indicated manufacturers were pushing to require GFCI protection for all circuits. The code making panel was pushing back only sightly, by adopting their proposal incrementally, by locations of highest risk first.

It does seem like could be a case of a manufacturer identifying how they can use government regulation to increase sales, and the willingness of government to use all the power of regulation that the govern don't protest against.

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    I liked the last part about manufacturers using regulations to increase sales. In my opinion, that does happen in this country. If the NEC doesn't explain why, then maybe this is the true reason why :). Also, thanks for the url pointing to the panels. That was interesting. I expanded one code-making panel at random and I did see some manufacturers on the panel, but many were "users". (I'm assuming a "user" is someone like an electrician that uses the items and not affiliated with a manufacturer). Commented Feb 27, 2020 at 17:14
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    This answer is much better than mine. It's much more conspiratorial and really makes it sound like NEC is about sales not safety. That appeals to my preconceived notions of how business and government are rigged against the little guy. This makes me distrust Code and puts me at ease with simply ignoring Code when I find it inconvenient, since now, I can rationalize that the annoying rule is probably there for corrupt reasons. Commented Feb 27, 2020 at 17:38
  • I'm sure some people on the panels do put safety first, but CMP-2 covers section 210, and Leviton, Schneider, and Eaton all sit on CMP-2 (and hold the two alternate seats). nfpa.org/codes-and-standards/all-codes-and-standards/… Commented Feb 27, 2020 at 19:48
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    I agree some people are just trying to make things safe for us. But, to some extent, I also do believe it's about revenue (so I'll add this to my list of conspiracy theories :)). And, maybe we're reaching the point of diminishing returns (small gains in safety for additional cost)--but no organization is going to admit that--it means they can be reduced in size, or go away :). As a side note, I've watched standards committees in my field take forever because manufacturers push for their own (i.e. patented) technologies (which requires everyone else to purchase a license from them). Commented Feb 27, 2020 at 21:37

There are many manufacturer representatives in code making panel and I believe there is push towards Increasing the sales. Remember back in 1999 consultants alarmed everyone about Y2K problems and received lucrative contracts to solve problems those were not existed. I still keep the book telling “Airplanes will fall of sky, because their clocks will fail in control software when midnight new year 2000 arrives.”. None of proven theories happened. Now the sales focus on Internet of the things (IoT), in industrial process it is IIoT. Process industries will need billions of sensors and switch to complete digital control to be competitive. Some Dishonest Sales people will never stop exaggerating.

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    I don't believe salespeople write the NEC or the UK wiring regs... Spoken to a couple of people involved in wiring regs and they are really experienced electrical engineers...
    – Solar Mike
    Commented Feb 28, 2020 at 16:06
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    There must be Conspiracy-Theory-of-the-Day-Club out there somewhere :-) Commented Feb 28, 2020 at 17:58
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    Hi Sean: Comments are generally used for asking clarifying questions of the OP (original poster) so we can provide a better answer. The OP is usually asked to edit his/her original post rather than comment. Your comment is more of an opinion than a clarifying question. And BTW, the Y2K problem was real. I'm an older IT guy who was closely aware of the Y2K issue. Only because of tons of Y2K mitigation work, nothing bad happened. That nothing bad happened is a great success story. I'm sure somewhere in Stack Exchange you could find info regarding the Y2K remediation efforts. Welcome to SE. Commented Feb 28, 2020 at 18:56
  • Y2K was real in instants of time keeping but in no way effected some of the fields used to wave the giant scary fund me flags. Such as the airplanes falling from the sky or cars crashing. There were Y2K issues but the vast majority were big spend projects that helped create the 2000 tech bubble. Commented Mar 30, 2022 at 10:41

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