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 Post subject: HV Line clearances- fatal Accident
PostPosted: Sat Nov 06, 2010 11:37 am 

Joined: Thu Feb 04, 2010 5:00 pm
Posts: 36
Location: Camp hill Pa
Recently in Lancaster PA. there was an incident where a worker for habitat for humanity was installing aluminium flashing on a new building that was located on a previously vacant lot. This building was about 54" from a high voltage line. The clearance required by the National Electrical Safety code (the other code that is used by utilities, and enforced by most PUC's including= Pa.) requires 90". The piece of flashing carried by the worker contacted the High-voltage line and the worker was electrocuted and fall 30 feet to the ground. Building designers and code inspectorss should assure that new construction clears existing lines. The NESC is available from the Institute of Electrical and Electronic Engineers. I have picture of the site which i Will try to post.


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PostPosted: Sat Nov 06, 2010 4:59 pm 
Sparks Level

Joined: Sun Dec 23, 2007 1:44 pm
Posts: 348
Location: Charlotte, NC
You are correct that someone should make sure that proper clearances or guards are in place.....unfortunately many times someone from the utility just happens to drive by and see the work happening before they can do anything about it. Construction supers/owners have some responsibility as well. I have had utility clients stop the work once they found out what was happening until they could safely cover the lines.

Don't know the voltage, but 8.5 feet is not a clearance I am comfortable with on an uncovered "high voltage" line and especially with workers and metal objects.

I once was involved with a site when the company moved a tank under a line that otherwise had proper clearances. They sent workers to the top of the tank with a long piece of rebar to check the product in the tank. Guy died, utility was sued and lost even though they knew nothing of the operation!

Extremely unfortunate, but does happen!


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PostPosted: Mon Nov 08, 2010 9:29 am 
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Joined: Tue Jan 13, 2009 5:00 pm
Posts: 584
The NESC applies to the utility, not to the building owner or the (presumably unqualified for line work) worker. Since it is a maintenance code, the utility is expected to correct any clearance issue as they arise. Clearance to the building that is; utility cannot maintain any amount of clearance to flashing or rebar that is being waved about.

Covers also do not make a line safe for unqualified workers to contact.

This is not so much about clearance or NESC, but about safe work practices. These objects should have never come within 10 ft of an energized line whether covered or not.


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PostPosted: Tue Nov 30, 2010 7:51 pm 

Joined: Sun Nov 28, 2010 10:06 pm
Posts: 2
Location: Ohio
They should have never came within 10 feet of the energized lines. This is all about electrical safe work practices. Thanks for the thread and info.


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PostPosted: Wed Jan 19, 2011 8:45 am 

Joined: Fri Jan 14, 2011 1:33 pm
Posts: 3
Location: ST. Clairsville Ohio
one source

Table 2.03a: Minimum Approach Distance to Any Energized Overhead Line or Part by
Unqualified Persons (General Public, General Industry, Construction Equipment)
Adapted to Colorado Springs Utilities System from OSHA 1910.333 & 1926.416
A: Voltage
Phase to phase
(volts)
B: Electrical Distance
phase to ground
(feet-inches)
0 to 35,000
(incl. neutrals &
secondary)
A. 10’-0” B. 10’-0”
115,000 10’-8" 10’-8”
230,000 13’-0” 13’-0”


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PostPosted: Sat Jan 22, 2011 9:24 am 
Sparks Level

Joined: Mon Mar 29, 2010 5:02 am
Posts: 136
In Alberta...

If work is done or equipment is operated within 7 metres (276") of an energized overhead power line, the employer must contact the power line operator to determine the voltage of the power line. Situations may arise in which work must be done or equipment operated near an energized power line at distances less than the safe limit of approach distance for that particular voltage. In such cases, the employer must notify the operator of the power line before beginning the work and obtain the operator’s assistance in protecting workers involved in the work. The operator may protect workers by deenergizing the power line, relocating it, isolating it, or performing some other equally effective action.

Here are the clearances that are required in Alberta:

0-750 volt INSULATED: 300 mm (12")
0-750 volt BARE: 1.0 m (40")
Above 750 volt Insulated: 1.0 m (40")
750v - 40 kv: 3.0 m (10')
69-72 kv: 3.5 m (137")
138-144 kv: 4.0 m (157")
230-260 kv: 5.0 m (197")
500 kv: 7.0 m (276")

Minimum height above ground of overhead power lines:

Pedestiran access areas: 3.6 m (142")
Residential Driveways: 4.1 m (161")
Areas where Agricultural Equipment is regularly used: 4.2 m (165")
Industrial/Commercial Alleys: 4.8 m (189")
Roads/Highways: 5.3 m (209")
Pipeline Right of Ways: 5.4 m (213")


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