Article 682 and Flood Plain

[beanland]

Article 682.10 states that no electrical equipment or their enclosures can be below the electrical datum. The datum is defined in 682.2(3) as 24 inches above the high water mark.

Given all the photos of flooding I have seen on the news, where houses are flooded to their eaves, wouldn't the electrical datum be above the roof. This means no electrical enclosures can be installed in the house. Is there limited applicability of this article that allows electrical equipment enclosures to be below this datum?

I am dealing with a building that is in a FEMA flood plain. The FEMA flood plain is 1' above finished floor. Therefore all electrical equipment enclosures must be 36" above the floor. 100 defines "equipment" as including "fittings" and defines "fittings" to include locknuts, bushing, "or other part of a wiring system..." Since conduit is an "other", does this mean there can be no conduit below 36" AFF?

 

[north star]

* + * +

beanland,

Not to worry......A lot of those flooded houses were most likely built
before a floodplain was even thought about.....If a Base Flood Elevation
[ BFE ] has been established in an area and a structure is built in that
area, then flood insurance is required......If flood insurance is not
obtained, then the insurance company does not have to pay for the
losses of any flooding of that / those structures.......It is a decisive
effort by the insurance industry to cover their losses when structures
are built in a designated floodplain area, and, ...FWIW, ...structures
are going to continue to be built in the flood plain areas.

Regarding your other question, Article 682.10 says that "No portion
of an enclosure for electrical equipment not identified for operation
while submerged shall be located below the electrical datum plane."
The structure would need to be raised, or the electrical enclosures
would need to be rated for submersion.

+ * + *

 

[jxofaltrds]

As I read it.

(3) In land areas subject to flooding, the electrical datum
plane based on (1) or (2) above is a horizontal plane
600 mm (2 ft) above the point identified as the prevailing
high water mark or an equivalent benchmark based
on seasonal or storm-driven flooding from the authority
having jurisdiction.

Which takes us back to:

(2) In land areas not subject to tidal fluctuation, the electrical
datum plane is a horizontal plane 600 mm (2 ft)
above the highest water level for the area occurring
under normal circumstances.

 

[hillbilly1]

Here you have to build above the "100 year flood" level, which means the floor level will be above that. On some cabins I have wired, this put the meter over 10' above ground level, the house built on stilts, breakaway underpinning, propane tanks strapped down and more.

 

[renosteinke]

You are misapplying the code.

You are asking about a 'normal' house, in an area that might flood. The NEC has no discussion, let alone rules. specific to that situation.

Look to the scope of 682. Equipment 'in and adjacent to bodies of water.' Bodies of water. By no stretch of the imagination did the authors intend to apply this to every place that might get wet when something goes wrong. Look at the examples cited by the code: aeration ponds, retention basins, irrigation channels.

By no means is 'adjacent to a body of water' to be construed as being the same thing as 'within the statistical area that will probably be flooded once every hundred years (the FEMA floodplain basis).

 

[jxofaltrds]

You are misapplying the code.

You are asking about a 'normal' house, in an area that might flood. The NEC has no discussion, let alone rules. specific to that situation.

Look to the scope of 682. Equipment 'in and adjacent to bodies of water.' Bodies of water. By no stretch of the imagination did the authors intend to apply this to every place that might get wet when something goes wrong. Look at the examples cited by the code: aeration ponds, retention basins, irrigation channels.

By no means is 'adjacent to a body of water' to be construed as being the same thing as 'within the statistical area that will probably be flooded once every hundred years (the FEMA floodplain basis).

So if a building department regulates;

"The Building Division is responsible for regulating development within the city's floodplains based on the standards established by the National Flood Insurance Program (NFIP)."

do any articles in the NEC need to be consulted in regards to a flood plain installation?

 

[don_resqcapt19]

If you can build the building under the guidelines from the building department for buildings in flood prone areas, there is nothing special in the NEC. Just the normal code rules.
Those rules in the building codes and flood insurance program guide lines will likely prohibit the installation of an equipment, electrical or otherwise, that can be damaged by flooding, within the flood plain elevation or some distance above that elevation. I don't think there is anything in the NEC that directly addresses construction in a flood plain.

 

[don_resqcapt19]

Our local flood plan ordnance says:

The lowest floor and all electrical, heating, ventilating, plumbing, and air conditioning equipment and utility meters shall be located at or above the flood protection elevation

The flood protection elevation is defined as 2 feet above the 100 year flood level as defined by FEMA.

 

[beanland]

Roll over, play dead

Roll over, play dead

I asked a state inspector and he advised that 682.2 is up the AHJ. Like others, the AHJ has decided the FEMA 1% in 30 year floor level is the basis for the datum and all electrical equipment shall be above that plane. We decided not to fight, we are raising our 324 square foot building by adding 4 feet of foundation height and filling the resulting 57 yard hole with rock. We must also build a stair system and platforms for the POCO to have meter access. It probably doubles the cost of the building but avoids a protracted fight with the AHJ that we may eventually lose. It will also look foolish having a raised building a few feet from others built on the flat, but it will never get water inside.