210.8(A)(2) and the Oxford comma

Srv52761

Senior Member
Location
lowa
Occupation
Energy Manager
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Theoretical questions.

Given: A stand alone accessory building workshop with slab on grade construction. The finished floor is the 6” thick concrete slab.
The top of the slab is 6” above grade, but the bottom of the slab is at grade. Certainly you would expect gfci to be required.

But now to the floor you add panels of 1” polyiso insulation and cover with osb sheets. Now the finish floor is 7” above grade.
Is gfci now required?

Next question…
In 2017 there is a comma after the word garages (blue) and in 2020 the comma is removed.
What does this mean?

Does it mean all garages must have gfci AND all accessory buildings that have a floor that is at or below grade level must have gfci?
Or does it mean that garages that have floors above grade level are also exempt?
I wish they would not include multiple concepts under the same code unless they wanted all the conditions to apply to all the concepts. … But maybe they do.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Given: A stand alone accessory building workshop with slab on grade construction. The finished floor is the 6” thick concrete slab.
The top of the slab is 6” above grade, but the bottom of the slab is at grade. Certainly you would expect gfci to be required.
Not necessarily. The floor can't be both 6" above and at grade at the same time.

I'd expect GFCI protection because of the concrete floor on grade.

But now to the floor you add panels of 1” polyiso insulation and cover with osb sheets. Now the finish floor is 7” above grade. Is gfci now required?
I would still say not required.

In 2017 there is a comma after the word garages (blue) and in 2020 the comma is removed. What does this mean?

Does it mean all garages must have gfci AND all accessory buildings that have a floor that is at or below grade level must have gfci?

Or does it mean that garages that have floors above grade level are also exempt?
I'd say the former: all garages, and only accessory buildings with a floor at or below grade.
 

kwired

Electron manager
Location
NE Nebraska
Maybe some clarification wouldn't hurt, but for most part a slab on grade floor still has finished surface above the surrounding grade, you typically want water to drain away from it instead of onto it. You may possibly have one end (like at an overhead door entrance that is essentially at same level as the exterior side, but that may be for limited area near that entry and then it slopes away.

A wash bay floor however is kind of the opposite.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
View attachment 2560609

Theoretical questions.

Given: A stand alone accessory building workshop with slab on grade construction. The finished floor is the 6” thick concrete slab.
The top of the slab is 6” above grade, but the bottom of the slab is at grade. Certainly you would expect gfci to be required.

But now to the floor you add panels of 1” polyiso insulation and cover with osb sheets. Now the finish floor is 7” above grade.
Is gfci now required?

Next question…
In 2017 there is a comma after the word garages (blue) and in 2020 the comma is removed.
What does this mean?

Does it mean all garages must have gfci AND all accessory buildings that have a floor that is at or below grade level must have gfci?
Or does it mean that garages that have floors above grade level are also exempt?
I wish they would not include multiple concepts under the same code unless they wanted all the conditions to apply to all the concepts. … But maybe they do.
While not the intent, the words in the code do not require garages with floors above grade to have GFCI protection. I have never seen a garage with a floor that was not either above or below grade level. The typical garage has a floor that is slightly above green.
 

kwired

Electron manager
Location
NE Nebraska
IMO grade level slab is one that sits on grade (on the dirt) even if the top of it is above grade.

Non grade level slab would be one that is elevated in any way that doesn't leave it 100% supported by the dirt below it. Most those would have some sort of decking that would have been used mostly as a form for pouring the slab and likely other framing supporting said decking/slab at certain intervals necessary for the application. I have seen a few but not too many residential garage floors that are concrete slab, but have trusses and a basement below them. I would say those are not "on grade" but at same time going back to 210.8(A)(2) for this discussion, it is still a "garage" and still would need GFCI protected receptacles, it would be other structures where you may not need GFCI and likely depending on use of said structure.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
I see the word "also" in (2020) 210.8(A)(2) as acting like a separator much like a comma. If it were deleted, the following is a barely plausible parsing:

"(Garages and accessory building) (that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use.)"

I say barely plausible because it doesn't really make sense to modify "garages" with the bit about "not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use." Garages are never intended as habitable rooms (if it's habitable, it's not a garage, you've converted it) and are always "storage areas, work areas, and areas of similar use."

But with the word "also" as a separator it should be parsed as:

"(Garages) and also (accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use.)"

Cheers, Wayne
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
I see the word "also" in (2020) 210.8(A)(2) as acting like a separator much like a comma. If it were deleted, the following is a barely plausible parsing:

"(Garages and accessory building) (that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use.)"

I say barely plausible because it doesn't really make sense to modify "garages" with the bit about "not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use." Garages are never intended as habitable rooms (if it's habitable, it's not a garage, you've converted it) and are always "storage areas, work areas, and areas of similar use."

But with the word "also" as a separator it should be parsed as:

"(Garages) and also (accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use.)"

Cheers, Wayne
Agree, because a house on a cliff could have a garage that the driveway is on grade and the ramp to the garage and the garage itself are out over a cliff. The code as written would not require GFCI protection in that garage.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
IMO grade level slab is one that sits on grade (on the dirt) even if the top of it is above grade.

Non grade level slab would be one that is elevated in any way that doesn't leave it 100% supported by the dirt below it. Most those would have some sort of decking that would have been used mostly as a form for pouring the slab and likely other framing supporting said decking/slab at certain intervals necessary for the application. I have seen a few but not too many residential garage floors that are concrete slab, but have trusses and a basement below them. I would say those are not "on grade" but at same time going back to 210.8(A)(2) for this discussion, it is still a "garage" and still would need GFCI protected receptacles, it would be other structures where you may not need GFCI and likely depending on use of said structure.
In building construction documents and drawings, grade level has always been the actual outside grade level. I stand by my statement that I have never seen a garage with its floor at grade level.
From a construction law source.
Finished Grade Level. - shall mean the average elevation of the finished surface of the ground abutting the external walls of the building or structure, exclusive of any embankment in lieu of steps.
 

kwired

Electron manager
Location
NE Nebraska
In building construction documents and drawings, grade level has always been the actual outside grade level. I stand by my statement that I have never seen a garage with its floor at grade level.
From a construction law source.
Finished Grade Level. - shall mean the average elevation of the finished surface of the ground abutting the external walls of the building or structure, exclusive of any embankment in lieu of steps.
Guess it depends on how much precision you want in measurement?

Garage will often be "grade level" or very near grade level particularly at vehicle doors, but opposite end of building may have floor well above or even below grade if building is on a hill, but most will consider the entire garage floor to fit under "grade level" I think?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Guess it depends on how much precision you want in measurement?

Garage will often be "grade level" or very near grade level particularly at vehicle doors, but opposite end of building may have floor well above or even below grade if building is on a hill, but most will consider the entire garage floor to fit under "grade level" I think?
I stand by my statement made in my PI on this issue....I have never seen a garage with a floor at grade level...everyone I have ever seen has a floor below or above grade level.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
I stand by my statement made in my PI on this issue
Don, what PI is that? I looked through the 2023 PIs and PCs and 2020 PIs and PCs, did I miss it?

I was looking for the CMP's statement accompanying the deletion of the "," but I couldn't find it. It was present in the 2020 First Draft but absent in the 2020 Second Draft. None of the PCs for the 2020 Second Draft proposed deleting it. I'm wondering if the deletion was intentional or not.

Cheers, Wayne
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Don, what PI is that? I looked through the 2023 PIs and PCs and 2020 PIs and PCs, did I miss it?

I was looking for the CMP's statement accompanying the deletion of the "," but I couldn't find it. It was present in the 2020 First Draft but absent in the 2020 Second Draft. None of the PCs for the 2020 Second Draft proposed deleting it. I'm wondering if the deletion was intentional or not.

Cheers, Wayne
That was my reply to a garage grade level comment...not what you are talking about.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
OK, but do you have any information on whether the comma deletion from 2020 First Draft to 2020 Second Draft was intentional? Or is this whole thread much ado about nothing?

I'm thinking that the comma deletion was just a "typo," but I have no definitive information about it.

As a point of reference, the current language of 210.8(A)(2) first appeared in the 1999 NEC, and it included the comma under discussion in this thread.

The previous 1996 NEC said:
"Garages and grade-level portions of unfinished accessory buildings used for storage or work areas."

In 1999 it became the following with the comma:
"Garages, and also accessory buildings having a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use."

The panel statement on the revision for 1999 was "The panel prefers the revision shown in order to clarify what types of accessory buildings are included." And so the original intent of the words that follow "accessory buildings" in 210.8(A)(2) is that they are applicable only to accessory buildings and not garages. And so 210.8(A) would apply to all garages.

The panel statement above is from pg. 92 of the pdf file at the link below:
https://www.nfpa.org/Assets/files/AboutTheCodes/70/NEC-ROPA-1998-Articles 90 to 240.pdf
 
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