ufer/ aluminum

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I have been recently flagged on running a #2 aluminum to the ufer and was wondering what code article says you can't use aluminum.. I see in 250.52 (8)(b)2 says not permitted as a grounding electrode.. 250.62 grounding electrode conductor says it is acceptable either I'm missing something or he is help me out on this hope it's not a dumb question
 
Is it considered to be in contact with masonry and earth if the ufer sticks out of the of the concrete a foot. or is the termination being less than 18 inches from earth

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infinity

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Is it considered to be in contact with masonry and earth if the ufer sticks out of the of the concrete a foot. or is the termination being less than 18 inches from earth

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Is the connection outside? If not the 18" rule does not apply. Also if it's insulated the bare conductor rule does not apply either.


250.64(A) Aluminum or Copper-Clad Aluminum Conductors.
Bare aluminum or copper-clad aluminum grounding elec-
trode conductors shall not be used where in direct contact
with masonry or the earth or where subject to corrosive
conditions. Where used outside, aluminum or copper-clad
aluminum grounding electrode conductors shall not be ter-
minated within 450 mm (18 in.) of the earth.
 

luckylerado

Senior Member
250.66(A) specifically gives a max size for aluminum but 250.66(B) does not list aluminum at all? Seems odd if aluminum is acceptable why it would not be included in A but not B.


250.66(A)
"...shall not be required to be larger than 6 AWG copper
wire or 4 AWG aluminum wire..."

250.66(B)
"...shall not be required to be larger than 4 AWG
copper wire."
 

kwired

Electron manager
Location
NE Nebraska
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Originally Posted by charlymurphy Is it considered to be in contact with masonry and earth if the ufer sticks out of the of the concrete a foot. or is the termination being less than 18 inches from earth

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Is the connection outside? If not the 18" rule does not apply. Also if it's insulated the bare conductor rule does not apply either.



250.64(A) Aluminum or Copper-Clad Aluminum Conductors.
Bare aluminum or copper-clad aluminum grounding elec-
trode conductors shall not be used where in direct contact
with masonry or the earth or where subject to corrosive
conditions. Where used outside, aluminum or copper-clad
aluminum grounding electrode conductors shall not be ter-



minated within 450 mm (18 in.) of the earth.
It also says where subject to corrosive conditions in there. That don't mean all locations would be subject - but needs to be considered.

I have never seen a rebar clamp that would accept aluminum conductor - one place to start.

As many underground aluminum conductors I have repaired in my lifetime so far - I'd never suggest terminating one below grade - so there about need to somehow be a splice onto a copper lead for the final run to the CEE or run the rebar out of the footing and into non corrosion environment to land the conductor. Termination in the footing likely has enough moisture that corrosion is going to be an issue.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I have been recently flagged on running a #2 aluminum to the ufer . . .


Is it considered to be in contact with masonry and earth if the ufer sticks out of the of the concrete a foot.

I can't tell from your words what your configuration of the "ufer", or Concrete Encased Electrode, is. Are you running a wire inside the footing as the grounding electrode, or are you connecting to the footing rebar? And if you are connecting to the rebar, is the rebar inside (at the point of connection of the Aluminum GEC - Grounding Electrode Conductor) the footing or is part of the rebar turned out so it sticks out of the footing. And if the rebar sticks out of the footing, is the rebar sticking out into the air above the basement floor, or is it turned out of the footing under the basement floor slab?

Tell us what the inspector saw at this one installation that he flagged.
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
250.66(A) specifically gives a max size for aluminum but 250.66(B) does not list aluminum at all? Seems odd if aluminum is acceptable why it would not be included in A but not B.

Ok...I get touchy with those words "maximum".....lol

being "not required" to be larger than those sizes is not the "Max Size" possible, just not required to be larger, but could indeed be larger if the designer so chooses. Clearly the maximum size is going to be dependent on your termination and the Engineers imagination. Now I will explain my opinion (for what it's worth)on the oddness of (B)...

1) the 2014 NEC change to Section 250.68(C)(3) to make it clear that the rebar could extend beyond the actual UFER (CEE) location as defined in 250.52(A)(3) and probably more of an issue that no one proposed a change to 250.66(B) to correlate with this change and permit AL to serve this purpose as permitted in 250.62. Typically the method of termination for the (UFER) would indeed bring 250.64(A) into play and limit the application anyway which is why it probably was not added to 250.66(B)....which in light of the changes to 250.68(C)(3) could use some tweaking in the 2020 process....bring on the 2020 NEC....)

I am more than sure a public input will be made during the 2020 cycle...by a future CMP 5 member.....:cool:
 

sandsnow

Senior Member
It also says where subject to corrosive conditions in there. That don't mean all locations would be subject - but needs to be considered.

I have never seen a rebar clamp that would accept aluminum conductor - one place to start.

ILSCO AGC-1 is listed for 1/0 to #14 AL/CU and rebar #4, #5 ,#6
 
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