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ekstra   ara
 Post subject: Contact Measurements at 34.5kV?
PostPosted: Wed Jul 07, 2010 6:33 am 

Joined: Wed Jul 07, 2010 5:12 am
Posts: 1
Location: Clarence, NY
Hi Gang,

I'm new here, but not to safety as I'm the Safety Engineer for a major University EH&S department. (I'll admit to being a bit behind the electrical curve as I'm a mechanical PE.)

My question: Following an investigation of a serious arc flash accident, I've had requests that instead of using the traditional non-contact testing, we instead use CONTACT testing. I've never heard of anyone doing this at distribution levels and cannot find any information on the web. I've basically told this person no way, I'm not going to tell our HV electricians to break critical boundaries with conductive test equipment.

Am I missing something?

Thanks,
Mark


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PostPosted: Wed Jul 07, 2010 6:56 am 
Sparks Level

Joined: Mon Mar 29, 2010 11:52 am
Posts: 110
Location: Yankton SD/ Lead SD
To actually follow the wording of 70E in regards to voltage testing, you need to use contact testers. How else would be able to test phase to phase, as well as, phase to ground. That being said, I personnally would use the a proximity tester first and then follow up with the contact tester.


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PostPosted: Thu Jul 08, 2010 6:51 am 
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Joined: Sun Dec 23, 2007 1:44 pm
Posts: 348
Location: Charlotte, NC
How bout a visible locked disconnect and grounds? By visible I mean an air break switch that you can see as open.


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PostPosted: Thu Jul 08, 2010 8:01 am 
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Joined: Mon Mar 29, 2010 11:52 am
Posts: 110
Location: Yankton SD/ Lead SD
acobb wrote:
How bout a visible locked disconnect and grounds? By visible I mean an air break switch that you can see as open.


I can see the exception for a GOAB switch, but then what do you do when you have a high voltage gear that has several switches and you only want to isolate one circuit?


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PostPosted: Thu Jul 08, 2010 12:33 pm 
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Joined: Sun Dec 23, 2007 1:44 pm
Posts: 348
Location: Charlotte, NC
Is this overhead, underground, or a combination of both?


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PostPosted: Thu Jul 08, 2010 12:51 pm 
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Joined: Mon Mar 29, 2010 11:52 am
Posts: 110
Location: Yankton SD/ Lead SD
I believe that K2QO was probably talking about OH stuff. What I was referring to was UG distribution. Strictly speaking, I do not think that proximity meters meet the letter of 70E. What I have reccommended at our facility is that they first use a prox meter, and then for added insurance use the contact meter.


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PostPosted: Thu Jul 08, 2010 4:29 pm 
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Joined: Sun Dec 23, 2007 1:44 pm
Posts: 348
Location: Charlotte, NC
Yeah.....I confuse easily these days! I thought he was talking OH but was not sure. With the switchgear problem, I don't get involved with 34.5 UG that much, but I would want a visible break before I had to put on grounds. The mistake of grounding it hot will be exciting to say the least. I saw a friend ground a hot 230 kV one day.....he did just fine with the 8' stick but it was a bit loud. Don't know if he had hearing problems later in life from it though.

Someone else will chime in I am sure!


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