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#112433 - 06/21/01 08:04 AM Would you do this?  
Admin  Offline

Joined: Oct 2000
Posts: 3,439
[Linked Image]

would you do this? Cadweld a #2 tinned cu to a propane tank. This was done at a cell tower site.

Submitted via Joe Tedesco

Tools for Electricians:

#112434 - 06/21/01 09:53 AM Re: Would you do this?  
Mike Wescoatt  Offline
Joined: Jun 2001
Posts: 161
Cedar City, Utah
I don't deal with this type of bonding, and I'm no brain surgeon, but I'd say that is bad... I'd at least have not bonded to the pressure vessel and welded to the foot a couple of inches away.

Stand back 50' is right...

Mike Wescoatt

#112435 - 06/21/01 01:07 PM Re: Would you do this?  

Bond to all metallic objects in the vicinity. It's a metal object. It is properly bonded.

I think it is the right thing to do.

Near a radio tower static electric would be a major concern.

Not bonding a fuel tank would be a big boo-boo.

#112436 - 06/21/01 05:16 PM Re: Would you do this?  
Bill Addiss  Offline
Joined: Oct 2000
Posts: 3,878

I'm with you on that for sure!


#112437 - 06/21/01 07:09 PM Re: Would you do this?  
ampznvoltz  Offline
Joined: Jun 2001
Posts: 9
Gretna, LA USA
Originally posted by Webmaster:
[Linked Image]

[b]Submitted via Joe Tedesco


I would have just drilled a hole in that leg looking thing underneath the tank and put a LUG there instead. Oh and please mount that lug with a nut and bolt!!!

#112438 - 06/21/01 07:46 PM Re: Would you do this?  
sparky  Offline
Joined: Oct 2000
Posts: 5,306
I'll second Joe's response, as to cad-welding a pressurized volitale vessel , they just don't make enough budwieser

[Linked Image]

#112439 - 06/21/01 10:36 PM Re: Would you do this?  
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
I agree that the tank should be bonded, but it is a pressure vessel and you just can't cadweld to the vessel itself. This is most likely an ASME certified vessel and any welding to the vessel must be made by an ASME certified welder using specific procedures. I highly doubt that the cadwelding process is certified for a pressure vessel. A bolt or cadweld to the support would be fine.


#112440 - 06/21/01 10:40 PM Re: Would you do this?  
Mike Wescoatt  Offline
Joined: Jun 2001
Posts: 161
Cedar City, Utah
In our 1.9 million gallon pool we bond everything with a crimp on lug and thread the metal if possible and use 316 stainless bolts, 1/4" or 3/8". This allows us to remove the bond to make repairs to the equipment or the bonding strap when needed. This makes maintenance a snap... well, as snappy as it can be for over 1000 documented bonding points

Mike Wescoatt

#112441 - 07/02/01 11:10 PM Re: Would you do this?  
John Steinke  Offline
Joined: Apr 2001
Posts: 518
Reno,Nv., USA
Others' comments are on the money- this is not an NEC problem, but a violation of the ASME Boiler & Pressure vessel code (and you thought the NEC was expensive!) From an engineering viewpoint, the cadweld process is hot enough to affect the temper/strength of the metal. The depth of the weld also introduces a stress riser/weak spot in the tank wall. It is also located in possibly the most vulnerable spot of the tank. Last but not least, if the tank was filled with anything -even water- at the time, the cadweld isn't even electrically sound. Another fine Darwin candidate.

#112442 - 07/03/01 08:34 PM Re: Would you do this?  
John Steinke  Offline
Joined: Apr 2001
Posts: 518
Reno,Nv., USA
(Webmaster note: This may duplicate an earlier post)
This is a good example of why you should know something about other trades.
This is not an NEC violation; rather, it violates the ASME "Boiler & Pressure Vessel Code."
This job violates training, technique, materials, and certification requirements.
From an engineering viewpoint, the cadweld is hot enough to change the temper of the metal, and introduce a stress riser. It does so in one of the most vulnerable areas- on the flat, near a seam. Even if the tank was filled with water at the time, there are penetration issues.
The ground should have been attached to the tank's foot.
The installer is a Darwin candidate.

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