Defining Basement

[mwm1752]

for those out there confused about GFCI protection in a basement - NFPA does have a definition

 

[suemarkp]

Now can you define a finished -vs- unfinished basement?

 

[mwm1752]

Now can you define a finished -vs- unfinished basement?

It doesn't matter per 210.8(A)

 

[infinity]

It doesn't matter per 210.8(A)

What about every code version prior to the 2020 NEC?

 

[romex jockey]

another sematic slippery slope.....~RJ~

 

[mwm1752]

What about every code version prior to the 2020 NEC?

The jest was because of the 2020 NEC - we didn't have to include 240 v & above 20 amp receptacles for GFI & recept spacing was minimal - but most could fathom what unfinished was due to the 2017 210.8(5) description in code. Not intended as habitable use IMHO

 

[kwired]

The jest was because of the 2020 NEC - we didn't have to include 240 v & above 20 amp receptacles for GFI & recept spacing was minimal - but most could fathom what unfinished was due to the 2017 210.8(5) description in code. Not intended as habitable use IMHO

What was considered unfinished has always been inconsistent. You can still have "habitable" use and bare concrete floor.

We used to have inspectors enforcing it as you at very least need to install receptacles per 210.52 requirements or else GFCI will be required.

 

[mwm1752]

What was considered unfinished has always been inconsistent. You can still have "habitable" use and bare concrete floor.

We used to have inspectors enforcing it as you at very least need to install receptacles per 210.52 requirements or else GFCI will be required.

so if it was wired per spacing they would consider it habitable - got it

 

[kwired]

so if it was wired per spacing they would consider it habitable - got it

Correct. That was 20 some years ago though when the GFCI rules were still reasonable as written.

Again why is a basement room more dangerous than if you placed the same room layout and finish types on a slab on grade floor?

 

[Dennis Alwon]

Correct. That was 20 some years ago though when the GFCI rules were still reasonable as written.

Again why is a basement room more dangerous than if you placed the same room layout and finish types on a slab on grade floor?

I assume the difference is that a basement is below grade and therefore less resistance to the earth

 

[rnatalie]

The NEC doesn't delve into any definion. Some of the other codes do and they're sometimes oddly interpreted when you're talking about a house built on a slope. For example. My front door is right at ground level (not even a step) but the back side has doors a floor below. My AHJ here considers my entire lower level to be "basement." I've seen othe jurisdictions that would not consider a walk-out level to be a basement. In my previous house, I had three stories the lowest level was a slab-on-grade. They considered my unfinished utility room that was on the lowest level to be a basement (and put a GFCI in there).

 

[kwired]

I assume the difference is that a basement is below grade and therefore less resistance to the earth

Why? Floor in either case is in contact with the same earth.

Moisture levels in soil may or may not tend to diminish at middle of the slab in either situation, kind of depends on other conditions. I can show you some places that should never had a basement because water table is high and is always a problem in those basements and others that never have dampness aside from whatever happens because of human actions within.

I'm guessing bare concrete floor is main factor that triggered these requirements way back in 1984 or 87 whenever it was that code first started requiring GFCI in basements and garages. I have seen many basements that have bare concrete though walls and ceiling are finished with some conventional method. Maybe place a large area rug in some those spaces but don't actually fix any kind of carpet in place. Others have seen with an epoxy finish applied, garages or slab on grade as well. Still pretty similar shock risk if you are standing on that barefooted.

 

[Dennis Alwon]

Kwired, why do they require the concrete encased electrode to be at the bottom of a footing?

 

[kwired]

Kwired, why do they require the concrete encased electrode to be at the bottom of a footing?

House on slab on grade often will still have a footing, or at least deeper around the outer edges and all in one pour, giving you similar ground potential on the surface in either situation.

Prior to 2020 change it made more sense, garages and unfinished basements were typically higher risk because concrete floor (likely on grade) is more likely to be exposed. But 2020 they decided all the basement is apparently higher risk, and don't matter if finished with insulating floor covering or not.

My basement is almost entirely capeted. mechanical and a storage room have bare concrete, bath has ceramic tile. A bar area has vinyl floor covering. Why should this require GFCI in the non exposed concrete areas other than bathroom that requires it anyway and within 6 feet of sink at the bar? You are isolated from the ground potential concrete. This is just manufacturers pushing their agenda to sell more product and hiding behind somewhat false safety claims as the basis. It is turning into eventually they will have GFCI requirement on everything whether justified or not. Don't get me wrong GFCI is a good thing, but is not needed for everything either.

 

[Fred B]

House on slab on grade often will still have a footing, or at least deeper around the outer edges and all in one pour, giving you similar ground potential on the surface in either situation.

Prior to 2020 change it made more sense, garages and unfinished basements were typically higher risk because concrete floor (likely on grade) is more likely to be exposed. But 2020 they decided all the basement is apparently higher risk, and don't matter if finished with insulating floor covering or not.

My basement is almost entirely capeted. mechanical and a storage room have bare concrete, bath has ceramic tile. A bar area has vinyl floor covering. Why should this require GFCI in the non exposed concrete areas other than bathroom that requires it anyway and within 6 feet of sink at the bar? You are isolated from the ground potential concrete. This is just manufacturers pushing their agenda to sell more product and hiding behind somewhat false safety claims as the basis. It is turning into eventually they will have GFCI requirement on everything whether justified or not. Don't get me wrong GFCI is a good thing, but is not needed for everything either.

Flooding potential higher than above grade, even if just from elevated ground water levels. You can recieve an unbelievable amount of hydraulic pressure from ground water, that will find any weak point in a wall to get in, so even in a finished basement a wet carpet can pose a risk of shock when manipulating equipment or plugs. I think also people if they see the basement beginning to flood will enter to try to "save" a washer or dryer vs if flooding starts to enter above grade area, people look more at real priorities and life issues to escape.
I think it is just actuarial statistics driven.

 

[kwired]

Flooding potential higher than above grade, even if just from elevated ground water levels. You can recieve an unbelievable amount of hydraulic pressure from ground water, that will find any weak point in a wall to get in, so even in a finished basement a wet carpet can pose a risk of shock when manipulating equipment or plugs. I think also people if they see the basement beginning to flood will enter to try to "save" a washer or dryer vs if flooding starts to enter above grade area, people look more at real priorities and life issues to escape.
I think it is just actuarial statistics driven.

Maybe. If flooded you now have conditions similar to a swimming pool, so maybe we need to comply with art 680 for basements as well? EGC to earth voltages become more of a hazard when you are immersed or partially immersed in water, which is what drives some the 680 requirements, so I guess maybe we should ban nearly all electrical in the vicinity sort of like we do for swimming pools?

Floods still have similar effects on at or not much above grade floors in many cases.

 

[mwm1752]

My garden level basement has windows all around the dwelling with windows at grade - is considered a basement by this definition. I have most of it covered with a padded manufactured wood product. I would like to see the statistics that more than likely are driven to appease the few rather than the many circumstances in a below grade floor. Finishing or building a space to be habitable in an area that will cause flooding above the floor is just bad construction in the 1st place.

 

[kwired]

My garden level basement has windows all around the dwelling with windows at grade - is considered a basement by this definition. I have most of it covered with a padded manufactured wood product. I would like to see the statistics that more than likely are driven to appease the few rather than the many circumstances in a below grade floor. Finishing or building a space to be habitable in an area that will cause flooding above the floor is just bad construction in the 1st place.

I don't know exactly what "garden level" means but presume you have something similar to what I have, one side of the house that level is basically at grade, the other side of house is well below grade. I have one side of the house and part of another side that is wood stud walls on that level. The remaining "basement" walls are poured concrete.

Yes it is still a basement per definition. Yes other than the mechanical room and one storage room is finished no different than what is typical for habitable rooms on any floor level. Carpet on quite a bit of it, vinyl tiles on floor in the bar area.

Would be very poor decision to finish like that if you were expecting flooding to occur.

The once in a hundred year floods don't count. They even tend to flood things that are well above grade at times. We got a taste of this in March 2019 somewhat statewide, or at least most the eastern half of the state saw fairly direct impact from it.

 

[mwm1752]

Garden level refers to the entire lower level is half below grade & half above grade on level surface surounding the entire structure.

 

[retirede]

Garden level refers to the entire lower level is half below grade & half above grade on level surface surounding the entire structure.

Then that’s not a basement according to the original post. See the figure on the left.