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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    "so it is written, so it shall be done" Feb 27 '20 at 1:05
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    This probably requires the NEC Handbook to answer, at a minimum, if not a rustle through the old files of when the change was made (as all NEC changes come with a fairly extensive paper trail) Feb 27 '20 at 1:07
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    @manassehkatz-Moving2Codidact The electrical code is far too complex to include detailed explanations for the history and motives that gave rise to specific rules - but that doesn't mean that good reasons don't exist. It behooves us to understand why sometimes.
    – J...
    Feb 27 '20 at 14:51
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    Walk across a dry carpet in dry conditions with some clothes. Note the static electricity generated. Wear the same clothes in the same conditions and walk across bare concrete. No static - you are well enough grounded. Now take the average uncompleted basement and compare it to yours. A wide range of differences. Many will be a lot less dry. The code cannot allow for all these. On average, people die in such conditions. Try not to. Feb 27 '20 at 14:56
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    Some basements are sufficiently damp and/or prone to frequent flooding that attempting to finish them would be crazy. Rather than try to guess which basements are sufficiently damp as to warrant a GFCI, I think the Standard treats a decision not to finish a basement as evidence that it might meet that criterion.
    – supercat
    Feb 27 '20 at 15:52

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. Feb 27 '20 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"? Feb 27 '20 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
    Feb 27 '20 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. Feb 27 '20 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
    Feb 28 '20 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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    Good answer. But I do buy those 10 packs once a year or so!
    – DMoore
    Feb 27 '20 at 4:22
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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. Feb 27 '20 at 12:52
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    @UnconditionallyReinstateMonica I suppose that works if you know what you're doing. But you know 99% of people do not, end up putting the LINE of the next recep on the LOAD of the last one... Which not only fails to accomplish your goal, but makes resetting a very difficult task. Feb 27 '20 at 15:58
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    The part about stats showing accidents in unfinished basements is interesting--thanks. However, I don't care for other parts of this answer. You focus on something I didn't ask about ("load vs line"). You're probably just trying to be thorough and want to warn about proper installation of GFCIs, but it kind of hides the answer. Also, I wasn't asking why because I "was sore". I was asking because I was curious (it really didn't make sense to me and an internet search didn't provide any answers). I guess that's the problem with text--it's too easy to get the wrong idea. Feb 27 '20 at 16:58
  • @AdirondackJim Good thoughts. Edited. Feb 27 '20 at 17:31

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.

  • 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). Feb 27 '20 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. Feb 27 '20 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/… Feb 27 '20 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). Feb 27 '20 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
    Feb 28 '20 at 16:06
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    There must be Conspiracy-Theory-of-the-Day-Club out there somewhere :-) Feb 28 '20 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. Feb 28 '20 at 18:56

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