Concrete encased electrode

[infinity]

Because there is contact on 2 sides I would bet that the concrete encase electrode in the case mentioned would have a lower ohm reading than 2 rods.

Why isn't #4 compliant--- Are you saying that because of the stone? I agree if one is not compliant then neither are compliant

Footings often have stone on both sides depending on their design and only the bottom is in direct contact with the dirt. If there is drainage on the inside and outside of the footing the sides are not in contact with the earth. This is common around here:

 

[Fred B]

Just got a call from a local inspector who just got back from a footing inspection and a concrete encase electrode. The electrician put 20' #4 in the footing and connected it to the rebar. We all know that 20' #4 is not necessary but that is what he did.

The problem is that the footing is set atop of crushed stone. I have never seen that before.....The code says direct contact with the earth. My guess is it is not compliant however it is better than 2 rods. I am not sure which way the inspector will go on this.

It does not say "earth". It says "the earth". If you dig out the dirt and put something else there it is no longer "the earth" it is in contact with.

In any case, the informational note makes it pretty clear that the foundation has to be in direct contact with the earth, and not sitting on something else.

OTOH, if he can get the inspector to accept the very weak argument that gravel is the same as "the earth", more power to the guy. However, it would probably be simple enough to just pound a couple rods and be compliant. He could still bond the rods to his wire and the rebar if he wanted to.

Is stone something other than earth? They dig up stone out of the earth, run it thru a crusher, and you have crushed stone. They dig up gravel, run it thru a screen and you have different grades of gravel base on size of aggregate.
I've yet to see a footer that is not put onto a bed of compacted crushed stone around here. Most will be excavated down to below our frost line and then recompacted with some sort of aggregate. If this is an issue, then we'll never get an UFER approved.

My biggest issue is the contractor that installs the footer is putting a nonconductive barrier under and around the footer, negating the attempted UFER.

My understanding also is some very large buildings simply require to excavate to below frost and to "undisturbed" soil and place footer directly there depending on compaction and load bearing ability of the "virgin soil". Soil composition plays a big roll in determing all of this. (Not a structural engineer but get the basic concept.)

 

[Jpflex]

Just got a call from a local inspector who just got back from a footing inspection and a concrete encase electrode. The electrician put 20' #4 in the footing and connected it to the rebar. We all know that 20' #4 is not necessary but that is what he did.

The problem is that the footing is set atop of crushed stone. I have never seen that before.....The code says direct contact with the earth. My guess is it is not compliant however it is better than 2 rods. I am not sure which way the inspector will go on this.

What about NEC exemption allowing rod to be buried 2 feet and laid horizontally when hitting bedrock or obstruction?

 

[Dennis Alwon]

What about NEC exemption allowing rod to be buried 2 feet and laid horizontally when hitting bedrock or obstruction?

I am not sure what that has to do with the issue at hand.