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#9605 - 05/07/02 07:04 AM 250.104(B) FPN ?  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Does anyone take the suggestion of the FPN cited above? Read on...
MERIDIAN — Residents in a north Meridian neighborhood are devastated by the Saturday accidental electrocution of Anthony Bartlett, 37. Bartlett, of 3416 50th St., died shortly before noon while trying to lower a television cable into a daughter's bedroom, said Clayton Cobler, Lauderdale County deputy coroner. "It was just a freak accident," Cobler said. "The air compressing unit outside had a short in it, and when it kicked on it shot 240 amps of electricity through the air ducts. He just happened to be laying over one of them at the time." Cobler said Bartlett's wife, Kristy, had been waiting for her husband to feed her the cable wire when she heard a strange noise. "She went up to see what was going on and when she put her hand on him she got shocked," he said. "It more or less pushed her away from him. She went and got a neighbor who turned off the breakers and called 911." Neighbor Sharon White said she arrived home to find emergency vehicles lining 50th Street. "About a dozen neighbors who were home when it happened were trying to comfort his wife, and the people who could not get to Kristy were comforting each other, even those neighbors who seldom spoke. There were people who really didn't know each other, acquaintances, who were holding each other. We're all so deeply saddened." Cobler said Bartlett was the father of two young daughters and a nurse at East Mississippi State Hospital. White said people who didn't know Bartlett personally knew him for his ready smile and wave. "Everyone who knew him knew he would have done anything for anybody," White said. "You always saw Anthony outside, working on his lawn and playing with his daughters. Every time I saw him, he waved. Both Anthony and his wife are the kind of people you wish for as neighbors. To say he'll be missed is a terrible understatement."


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#9606 - 05/07/02 01:28 PM Re: 250.104(B) FPN ?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Redsy,
While the bonding suggested in the FPN will provide some additional safety, if the fault is directly to the ductwork, the fault return path may not be able to carry enough current to open the OCPD. If the OCPD does not open, there would be voltage between the duct and ground". However, if the compressor unit was properly grounded, why didn't the required EGC at the unit itself clear the fault? The grounding suggested in the FPN should not have been required to prevent this accident. The code required EGC should have prevented this tragic accident.
DoN(resqcapt19)


[This message has been edited by resqcapt19 (edited 05-08-2002).]


Don(resqcapt19)

#9607 - 05/07/02 10:21 PM Re: 250.104(B) FPN ?  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Don,
I'm thinking that the ckt. feeding the AC must have been skinned while being pulled. Therby energizing the duct, but not the AC unit housing. He must also have been grounded himself in some manner.


#9608 - 05/08/02 10:38 AM Re: 250.104(B) FPN ?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Redsy,
I didn't think of that. My projects are almost all rigid conduit. If the duct was directly energized by a skinned cable, the application of the FPN may help.
Don(resqcapt19)


Don(resqcapt19)

#9609 - 05/08/02 01:19 PM Re: 250.104(B) FPN ?  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,875
NY, USA
Sheesh!!

How many errors can you spot in this account?

[Linked Image]
Bill


#9610 - 05/08/02 02:27 PM Re: 250.104(B) FPN ?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
240 amps??? I think they meant volts, but then surely if this was residential it could only be 120 to ground anyway. Trust the press to get the technical bits wrong.....

Isn't there already an NEC requirement for A/C ducting to be bonded, either directly or via the ground wire to the compressor unit?


#9611 - 05/08/02 03:01 PM Re: 250.104(B) FPN ?  
motor-T  Offline
Member
Joined: Nov 2001
Posts: 280
Girard, Ohio, USA
Pawlik that was my question how can 240 volts be at the duct ? When in residential can only be 120 to ground at any point on the system. If there was 240 volts on that duct would that not be a bolted fault, or one great enough to trip the breaker ?
Has anyone seen the official investigation report. The whole article sounds a bit bogus. If this was a pre-existing condition there must have been a touch voltage around the house, even the house rigisters would have been hot when the AC unit was on. The furnace too would be energised when the unit was running.
I hate to see any kind of accident especially electrical accidents, but this just doesnt sound right.
-Mark-


#9612 - 05/08/02 04:06 PM Re: 250.104(B) FPN ?  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,875
NY, USA
You guys picked up one of the things I was talking about (where does 240v come from?)

Redsy,

Wouldn't the ductwork be live all the time if a skinned cable was touching it? If, indeed there was some relationship with the unit coming on as the report states this must've been an ungrounded installation.

Bill


#9613 - 05/08/02 06:52 PM Re: 250.104(B) FPN ?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Maybe an ex-British journalist who doesn't realize that the 240V in American homes isn't quite the same as the 240V in British homes! [Linked Image]

O.K., how about this for a possibility: The skinned cable mentioned had energized the ductwork -- at 120V! -- and the man was well insulated from ground as he came into contact with it, so he felt nothing (or perhaps just a very light buzzing that he dismissed as nothing to worry about).

It says he was threading a TV cable, so if one end were already connected to equipment in the house or to the rooftop antenna (or maybe a cable-TV service), the outer braid could have been grounded. As he worked on the cable he happens to grab hold of the bare end.....


#9614 - 05/09/02 06:37 AM Re: 250.104(B) FPN ?  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Guys,
I believe the report is true because it came from the Safeteng.com website. And all of the players names and locations are there.
The media always gets technical info. wrong, so I don't sweat the poor technical terminology.
If he was in an attic or crawl space and sweating and came in contact with an energized duct (120 volt) and ground this is the likely result. Espscially if he was laying across the duct, which would greatly increase his contact area thereby lowering the effective resistance of his body.
I don't find this scenario implausible at all.


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