One hole straps used to strap ground wire

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hunt2871

Member
Location
Carlsbad, NM
I am doing QA on a government project in a level 2 nuclear facility and the electrical contractor on the project has used a bunch of 1/2" steel one hole straps to strap bare copper equipment grounding conductors and bare copper grounding electrode conductors to concrete slabs and pillars. The straps have been "mashed" in order to fit the 4/0 copper better. I know this is pretty standard practice...I have done it hundreds of times myself...but I have never thought that it was exactly kosher. There is the issue of dissimilar metals but I also think there is a UL listing issue...I doubt seriously if a standard 1/2" one hole strap is listed for this application.

My goal here is to find a way to justify the use of these straps. I don't want to force the contractor into replacing them but I also want to make sure the tax-payer is getting what they pay for. The job specs cover all bases from the NEC to best industry practices.

Any thoughts?
 

iwire

Moderator
Staff member
Location
Massachusetts
Do they specs include how to secure the GEC?

As far as the listing I agree they are not listed for it however the AHJ still has the authority to allow it.
 

hunt2871

Member
Location
Carlsbad, NM
what product is listed to strap bare wire to anything? the steel straps are probably zinc plated.

They are zinc plated. There are copper one hole straps used in lightning protection applications as well as copper one straps used to strap copper tubing although I doubt they are listed for this application.

I will do some research on the zinc plating....that may be all I need! There are no "inspections" on this project short of about 20 people with various ideas about how things should be done....but the final AHJ would be me and I am leaning in that direction but I want to make certain that the wire isn't going to disappear at the straps in a couple of years....just trying to dot the "T's" and cross the "I's" without crossing too many eyes....
 

kwired

Electron manager
Location
NE Nebraska
what product is listed to strap bare wire to anything? the steel straps are probably zinc plated.

My thoughts as well - show me a product that is listed for the purpose and maybe I will consider the practice mentioned to be inadequate. I do believe that there probably should possibly be some isolation between the copper and zinc though how often do we see bare copper pulled through galvanized pipe/tubing?
 

hunt2871

Member
Location
Carlsbad, NM
Do they specs include how to secure the GEC?

As far as the listing I agree they are not listed for it however the AHJ still has the authority to allow it.

Specs are generic as usual....in typical government and NQA-1 fashion they reference about 40 different industry specific requirements in a CYA situation. And of course there is the all governing Engineer of Record "out" that supersedes all other requirements...what is referred to in the industry as "pencil whipping" requirements. Basically the EOR can sign off on anything and it is acceptable....happens way more often than one outside of the industry would think....

Officially I serve as the AHJ but the EOR can over ride that also.

I am leaning toward accepting the application but I am trying to be as conscientious as possible. I have used one hole straps for this application myself hundreds of times in the past but I never really thought it was 100% correct.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I don't know that there is listed product but clearly 1/2" EMT straps are not and the fact they are listed brings 110.3(B) into it.

Hopefully the AHJ is reasonable.

Just because something is listed for a specific purpose does not preclude one from using it for a different purpose. otherwise it would not be permitted to use conduit as a sleeve instead of a raceway.
 

iwire

Moderator
Staff member
Location
Massachusetts
Just because something is listed for a specific purpose does not preclude one from using it for a different purpose. otherwise it would not be permitted to use conduit as a sleeve instead of a raceway.

Have you read 110.3(B)? It directly prohibits using listed products outside their listing.

When we do use EMT for other purposes the inspector can cite 110.3(B), luckily most inspectors are reasonable.
 

hunt2871

Member
Location
Carlsbad, NM
Is a 'level 2 nuclear facility' covered by the NEC?


A government owned level 2 nuclear facility is not UNLESS the contract documents require the work to be done according to the NEC...and in most cases this is the case. The Specifications for most projects are generic and list any and all relevant requirements, in this case electrical work must be done in accordance with the NEC along with 30 or so similar regulations. You know how engineers are....why pigeon hole yourself with one requirement when there are several hundred that may apply loosely?

I run into this all of the time on DoD facilities around the world. It was much simpler when I was doing plan and spec and design build commercial and industrial projects where all you have to adhere to is the adapted NEC and local codes and of course the AHJ. When you combine bureaucrats and engineers with no profit motive the hi-jinx that they can get up to is mind boggling at times. It makes for some very profitable projects though!
 

hunt2871

Member
Location
Carlsbad, NM
Tempest procedures are another PITA at government facilities.


No kidding....ever run a piece of RGS inside of another piece? I have...communication duct bank at an Embassy in the UK....12 runs of 4" ran inside of 12 runs of 6" RGS and encased in concrete.....welded 6" hubs at man holes with the 4 inch ran into the wall of the manholes....talk about a NIGHTMARE...and expensive...and for sure and certain not at all listed for such an application.

is it any wonder we are $20 Trillion in debt? A trillion here, a trillion there....pretty soon it adds up to some real money!
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Have you read 110.3(B)? It directly prohibits using listed products outside their listing.

When we do use EMT for other purposes the inspector can cite 110.3(B), luckily most inspectors are reasonable.

(B) Installation and Use. Listed or labeled equipment
shall be installed and used in accordance with any instructions
included in the listing or labeling.

It does not actually say you cannot use it for unlisted purposes. only that you have to follow the directions. My guess is that the directions for one hole straps tell you how to use it with EMT but don't tell you it cannot be used for other purposes.
 

iwire

Moderator
Staff member
Location
Massachusetts
It does not actually say you cannot use it for unlisted purposes. only that you have to follow the directions. My guess is that the directions for one hole straps tell you how to use it with EMT but don't tell you it cannot be used for other purposes.

However you want to phrase it the result is the same, it's an AHJ call if I can use listed EMT clips for cable. (And I have)

I have never seen directions for a 1 hole strap but they do have the UL mark and the product it is designed for stamped into it.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
If you check, Arlington or one of the other companies do have one hole straps for ground wires.
I have 2 different sizes out in the van, it's been quite a while since I purchased them and I think one size does #6 and the other #4 or #2. Shows how much I actually use them.

Found one of them--- Arlington 311 1/4" bare copper one hole strap made I believe plated steel.
I ve used the 3/8" version for mc which worked well for 1/0 with a little crimp.
 
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curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
If you check, Arlington or one of the other companies do have one hole straps for ground wires.
I have 2 different sizes out in the van, it's been quite a while since I purchased them and I think one size does #6 and the other #4 or #2. Shows how much I actually use them.

Found one of them--- Arlington 311 1/4" bare copper one hole strap made I believe plated steel.
I ve used the 3/8" version for mc which worked well for 1/0 with a little crimp.

Those Arlington straps are for steel armored ground not bare CU ground wire.
 

kwired

Electron manager
Location
NE Nebraska
Have you read 110.3(B)? It directly prohibits using listed products outside their listing.

When we do use EMT for other purposes the inspector can cite 110.3(B), luckily most inspectors are reasonable.
Which gets into where do you draw the line. Listed raceway strap supporting a plumbing pipe - can EI reject that? Plumbing inspector likely doesn't other then if it introduces a dissimilar metals problem.

How about in an industrial facility running electrical raceway but using it for pneumatic lines instead of conductors?
 
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