christmas lights

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jhaas5

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Our mill hangs (2 wire) xmas lights on a chain link fence around our facility, the fence isn't bonded. I have told them not to do this because of the possibility of the fence becoming hot. Which section of the code covers this??
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I am not sure which part of the Code covers this situation but there is a mention of the means of attachment of light such as temporary, festoon and decorative lighting must be done by the use of insulating material rated at least to the voltage of the lights.

The use of GFCI's for any outdoor application is also mentioned in the 05 NEC. Following those two rules should make for a safe display.

Happy Holidays,

Marky the Sparky
 
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roger3829

Senior Member
Location
Torrington, CT
jhaas5 said:
Our mill hangs (2 wire) xmas lights on a chain link fence around our facility, the fence isn't bonded. I have told them not to do this because of the possibility of the fence becoming hot. Which section of the code covers this??
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Isn't the metal fence connected to metal poles that are buried into the ground?
 
celtic

celtic

Senior Member
Location
NJ
K8MHZ said:
I am not sure which part of the Code covers this situation but there is a mention of the means of attachment of light such as temporary, festoon and decorative lighting must be done by the use of insulating material rated at least to the voltage of the lights.
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:confused:
Does that mean millions of homeowners are in violation when they put lights on their railings?


K8MHZ said:
The use of GFCI's for any outdoor application is also mentioned in the 05 NEC. Following those two rules should make for a safe display.
Click to expand...

I'd stick to the GFI and not worry too much about it.
 
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jhaas5

Member
fence

fence

roger3829 said:
Isn't the metal fence connected to metal poles that are buried into the ground?
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Yes there is metal poles in the ground, but their not bonded back to the panel, earth ground has a high impedance so if the hot wire touches the fence it wouldn't trip the breaker! if the fence was bonded back to the panel it would have a low impedance and the breaker should trip.
 
480sparky

480sparky

Senior Member
Location
Iowegia
jhaas5 said:
Yes there is metal poles in the ground, but their not bonded back to the panel, earth ground has a high impedance so if the hot wire touches the fence it wouldn't trip the breaker! if the fence was bonded back to the panel it would have a low impedance and the breaker should trip.
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So the danger is in the lights, not the fence. Check the lights to make sure the unsulation on them is acceptable, put in a GFI recep and call it good.
 
charlie b

charlie b

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Location
Lockport, IL
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Semi-Retired Electrical Engineer
roger3829 said:
I have seen a live wire come in contact with a metal fence that did trip the breaker.
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That is certainly possible. If for example the resistance of the ground rod to planet Earth was 10 ohms, attaching a 120 volt source to the fence would add 12 amps to the existing load. Depending on how much "normal" load was running at the time, that extra current might be enough to cause the breaker to trip.

But a higher ground resistance is more likely, and it is more likely that this scenario would not trip a breaker. That is why we are not allowed to take credit for planet Earth as being part of a path for clearing a 120 volt system fault.
 
cowboyjwc

cowboyjwc

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Location
Simi Valley, CA
I used to do a 10,000+ light Christmas display that people came from all over town to look at. When people used to ask where I lived it was usually followed by, "oh you're the house with all the lights."

You don't even want to know how it was all connected.

I understand your concerns, but it's for the holidays, at least they're doing something. I sure wouldn't want to be the Grinch.;)
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
LarryFine said:
Right. Fences don't shock people . . . ;)
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I got called to one of the prisons we maintain for a report of the fence shocking people. I got there and put meter on fence to ground and I got 97v. After looking around we found that some one had installed new horseshoe stakes. The guy had driven a rod down beside the underground 5200v primary and nicked one of the conductors which was close to the fence. This let the primary "bleed" over to the fence post which made the fence hot. If he would have been 1/4" closer he may not have lived for the horseshoe tournament
 
TOOL_5150

TOOL_5150

Senior Member
Location
bay area, ca
ceb58 said:
I got called to one of the prisons we maintain for a report of the fence shocking people. I got there and put meter on fence to ground and I got 97v. After looking around we found that some one had installed new horseshoe stakes. The guy had driven a rod down beside the underground 5200v primary and nicked one of the conductors which was close to the fence. This let the primary "bleed" over to the fence post which made the fence hot. If he would have been 1/4" closer he may not have lived for the horseshoe tournament
Click to expand...

This is something I think about every time I drive a ground rod.

~Matt
 
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