Grounded/bonded box?

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  #1  
Old 11-17-12, 09:00 AM
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Grounded/bonded box?

Hi I have a older 1978 square d box/panel.Am trying to figure out where if it even is bonded /grounded.
I did ohms test from neutral bar to panel and got 0 even though i see no green screw anywhere.There is a alluminum #4 or 6 at top of neutral bar going to copper pipe..
How is the box able to show 0 ohms(neutral to panel box? with no green bonding screw?Name:  IMAG0116.jpg
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  #2  
Old 11-17-12, 09:27 AM
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The bonding screw will not be green. The screw may be there masquerading as one of the screws in the ground/neutral bar.


on edit: the bonding screw isn't always green especially with older panels.
 

Last edited by PJmax; 11-17-12 at 09:29 AM. Reason: correction
  #3  
Old 11-17-12, 10:47 AM
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Working from memory, I don't think the bonding screw had a green head back in the 70s. I know your panel is older, but there should be a label inside the left side of the panel box that probably has an illustration that will show where the bonding scew should be installed. I am thinking it was the left side, look on the right side too.
 
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Old 11-17-12, 02:04 PM
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Thanks,is there a website that will tell me this , if i get the panel information?
So many newbie electrical "experts"dont realize old grounding/bonding screws are NOT all green..many state no green=not bonded..(i believe mine is but want to look at manufacture info to confirm )
 
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Old 11-17-12, 02:27 PM
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I don't think you'll find a website with that information, but you always could submit a question to or call Schneider Electric.

Contact Us - Schneider Electric United States

If your meter showed 0 ohms resistance between the box and the neutral bar, it is bonded. Why do you need more info than that? What I would have done is just checked for continuity between the neutral bar and the box.
 
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Old 11-17-12, 09:47 PM
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Thanks,is there a website that will tell me this , if i get the panel information?
What did you find on the label on the inside of the panel door?
 
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Old 11-18-12, 07:07 AM
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What did you find on the label on the inside of the panel door?
The panel is a Square D QO series from the late 70s. Square D sells the covers, whether flush or surface, separately. The label inside the panel door only gives data on the cover and door and not data on the panel. The panel data label is located inside the panel box, I think on the left side.
 
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Old 11-18-12, 11:46 AM
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here is a pic from door.still looking for inside info . is series L7 .Qoc 20mw225[ATTACH=CONFIG]5661[/ATTACH]
 
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Old 11-18-12, 04:37 PM
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Had also meant to ask when atatching the #4 aluminum to copper pipe which clamp should i use, the allow copper or aluminum?
 
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Old 11-18-12, 05:24 PM
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The label should have a diagram of the neutral bar with the bond screw location.
 
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Old 11-18-12, 05:41 PM
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was already on it from 70s -goes to neutral bar from pipe
 
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Old 11-18-12, 05:49 PM
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The bond screw goes in the empty hole to the right of the large neutral lug.
 
  #13  
Old 11-18-12, 06:10 PM
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Aluminum can be used for indoor grounding of the neutral to the water service, but cannot be used to the ground rod outside. I believe the issue with grounding with aluminum wire to the ground rod would be that you are not allowed to have an aluminum termination within 18" of earth which is corrosive. Bottom line is, use copper wire to a ground rod. If you have a #4 aluminum water pipe ground wire, you must have a 100 amp service.....correct? A 200 amp service requires either a #4 copper or #2 aluminum ground wire to the water service. Use a water pipe clamp like one of these and DO NOT allow the aluminum ground wire to come in contact with any masonry or concrete surfaces!

Ground Clamps for Bare or Armored Ground Wire/Grounding & Bonding Fittings
 
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Old 11-18-12, 06:39 PM
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went to that link..which one though for mine(aluminum to copper) -the zinc or bronze?
 
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Old 11-18-12, 06:43 PM
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Item #: GCB50100
Bronze Ground Clamp for Bare Wire and Pipe Size 1/2" to 1"
1/2" to 1" ground clamps are used to ground bare copper or aluminum wires to water pipes, ground rods, rebar or other structural members that will ens(more....)
Item #: GCBZ50100
Zinc Ground Clamp for Bare Wire and Pipe Size 1/2" to 1"
1/2" to 1" ground clamps are used to ground bare copper or aluminum wires to water pipes, ground rods, rebar or other structural members that will ens(more....)
Looks to me like either one would work fine, but I always prefered zinc diecast for aluminum ground wire and bronze for copper ground wire. Either clamp will work fine on your copper water pipes.
 
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Old 11-18-12, 08:13 PM
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Just remember 1/2 inch galvanized steel pipe is larger then 1/2 inch copper pipe so be sure it is sized for copper pipe.
 
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Old 11-18-12, 10:52 PM
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the pipe is copper and wire #4 aluminum...no galvanized pipe
I wouldnt need one thats made out of what the split bolt connectors for these type connections (copper to aluminum )are would i ?
 
  #18  
Old 11-19-12, 03:20 PM
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Im going to use a side bar to neutral bar to bond it with a #2 copper.When inspected should there be any problems with that type bonding?
Here is a pic[ATTACH=CONFIG]5693[/ATTACH]
 
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Old 11-19-12, 06:27 PM
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I wouldnt need one thats made out of what the split bolt connectors for these type connections (copper to aluminum )are would i ?
No, you aren't connecting aluminum wire to copper wire, you are connecting aluminum wire to a copper pipe. At no time will your aluminum ground wire be in direct contact with the copper pipe. Both the zinc and bronze clamps are rated for either copper or aluminum ground wire, either is acceptable.

Im going to use a side bar to neutral bar to bond it with a #2 copper.When inspected should there be any problems with that type bonding?
Do you mean to bond the panel box to the neutral bar? If so, that would be fine. #2 is a bit large, I believe a #4 or #6 would be adequate.
 
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Old 11-19-12, 07:20 PM
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That's for bonding..via box....(the copper wire pic)


I already used the brass pipe connector..not in picture..to attatch the #2 aluminum to the copper pipe with anti oxidant on the aluminum.
 
  #21  
Old 11-19-12, 10:27 PM
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is this what id need for attatching the aluminum to copper pipe
NOTE-the A306CX---[ATTACH=CONFIG]5722[/ATTACH]
 
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Old 11-20-12, 05:04 PM
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Now I am confused. You just said:

I already used the brass pipe connector..not in picture..to attatch the #2 aluminum to the copper pipe with anti oxidant on the aluminum.
Why would you need that other connector?
 
  #23  
Old 11-20-12, 05:46 PM
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yes i did connect that one i spoke on and then asked if that other one-last pic- was the one i should have used.. it now has this one on the copper pipe w anti corrosion on the aluminum area . -pic[ATTACH=CONFIG]5753[/ATTACH]
 
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Old 11-21-12, 05:19 PM
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it now has this one on the copper pipe w anti corrosion on the aluminum area
It looks fine to me. I don't know why it has the little siver colored strapp and 2 screws, but I don't see a problem if that's the way it came.
 
  #25  
Old 11-21-12, 05:27 PM
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.



It almost looks like an insulation strain relief clamp if the wire was fed from the other direction.



.
 
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Old 11-21-12, 06:36 PM
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Eve went to electric supply shop and they had nothing for AL to copper groundy grounding..you shouldn't have to go online for what is NEC code ..AL to copper pipe..so many older homes have this .
 
  #27  
Old 11-22-12, 05:44 AM
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Water pipe ground clamps like these are available at any supply house, most hardware stores and big box stores.

Zinc Ground Clamp for Bare Wire and Pipe Size 1/2" to 1"

Bronze Ground Clamp for Bare Wire and Pipe Size 1/2" to 1"

These are approved for both copper and aluminum wire.
 
  #28  
Old 11-22-12, 08:31 PM
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all the zinc ones ive seen in the stores and the electric supply shop do not say for AL and neither do the other ones they had-including the brass one i hadName:  IMAG0162.jpg
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  #29  
Old 11-22-12, 08:59 PM
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What you presently have installed is ok for aluminum ground wire.
 
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Old 11-22-12, 09:29 PM
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Now this is odd-
exact same item i have from pic and it DOES state AL on it-only online though..
Im gonna use the zinc one after all..
 
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Old 11-22-12, 11:12 PM
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The picture in post #23 is for use with an armored grounding electrode conductor. The steel strap holds the armor in place.
 
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Old 11-23-12, 06:03 AM
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Here is a Blackburn from T&B that is commonly stocked at many supply houses. It's also dual rated for either CU or AL ground wire.

Frost - BLACKBURN AJ 1/2 TO 1 INCH WATER PIPE DUAL RATED GROUND CLAMP (WIRE SIZE #14 - 1/0 AWG) CU/AL
 
  #33  
Old 11-23-12, 06:11 AM
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The picture in post #23 is for use with an armored grounding electrode conductor. The steel strap holds the armor in place.
It looks as if you are exactly correct, Furd. I have never seen an armored grounding conductor before and don't really know why the armor would be required, but it may be common in some areas or in some industries.
 
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Old 11-23-12, 07:45 AM
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Joe, It was real common back in the late 50's and 60's. It was called baby ground. Had a single copper conductor with a small steel spiral. My house here was built in 1958 and it had it originally.
 
  #35  
Old 11-23-12, 11:30 AM
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NEC has stated pretty much forever that a Grounding Electrode Conductor #6 or larger does not need any additional mechanical protection. That implies that using a smaller (#8) conductor DOES require additional protection. Those older GECs on 60 and 100 ampere services used an armored #8 copper conductor.

Today we simply specify #6 for smaller services or for sub-panels in outbuildings to get away from the additional protection requirement.
 
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Old 11-24-12, 05:46 AM
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NEC has stated pretty much forever that a Grounding Electrode Conductor #6 or larger does not need any additional mechanical protection. That implies that using a smaller (#8) conductor DOES require additional protection. Those older GECs on 60 and 100 ampere services used an armored #8 copper conductor.

Today we simply specify #6 for smaller services or for sub-panels in outbuildings to get away from the additional protection requirement.
Good point, Furd. I have seen a lot of commercial and residential services from the 40s, 50s and 60s (some from 20s and 30s too), but still don't recall seeing an armored grounding conductor. Like I said before, it may be something that was more prevalent in certain areas.
 
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