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Zog
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Post subject: Compliant or not? Posted: Wed May 12, 2010 6:17 pm |
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Joined: Mon Jun 02, 2008 11:58 am Posts: 1103 Location: Charlotte, NC
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What do you guys think about this?
http://www.graceport.com/files/ChekVolt.pdf
Does this meet the OSHA and 70E requirements for verifing equipment denergized? Or L-D-L check?
Look at the installation before deciding, I have seen many of these with a similar design but always found a potential failure or flaw in the concept but this one looks good to me. Assuming the NC detector is verified before and after the test.
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tjgraf
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Post subject: Posted: Thu May 13, 2010 5:06 am |
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Joined: Mon Mar 09, 2009 5:52 am Posts: 10
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non contact
If you tested NCVD prior to, and after insertion in these things, I'd say you could safely use this.
What if you had a little insulated cover over some live terminals on the front of the device, and you opened the cover and tested with a contact device. How is that seriously worse than this? Your live terminals could be connected with some very small size wire, say # 24. That would be a fuse in and of itself. Or you could have some very low current fuses in line with each phase terminal. If you test with a "contact device", i.e. your Fluke DVM, you have a more positive proof that you are de-energized, right? What else am I forgetting? I'm new at this stuff.
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Zog
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Post subject: Posted: Thu May 13, 2010 5:41 am |
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Joined: Mon Jun 02, 2008 11:58 am Posts: 1103 Location: Charlotte, NC
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tjgraf wrote: If you tested NCVD prior to, and after insertion in these things, I'd say you could safely use this.
What if you had a little insulated cover over some live terminals on the front of the device, and you opened the cover and tested with a contact device. How is that seriously worse than this? Your live terminals could be connected with some very small size wire, say # 24. That would be a fuse in and of itself. Or you could have some very low current fuses in line with each phase terminal. If you test with a "contact device", i.e. your Fluke DVM, you have a more positive proof that you are de-energized, right? What else am I forgetting? I'm new at this stuff.
Fuses could be an issue, a blown fuse could give a false negative. I agree a direct contact test is more reliable and I would use one to verify if I was to work on this panel.
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Wormfood
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Post subject: Posted: Thu May 13, 2010 8:14 am |
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Joined: Mon Mar 29, 2010 8:31 am Posts: 24 Location: Jonesboro, AR
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I would refrain from using it. What happens when the insulator degrades, or someone defaces the probe, to much of an issue for someone to get shocked. Adds another PM routine to keep up with, plus the cost of the probe, and I would still want a true reading (voltmeter) to ensure that the panel was dead before anywork down stream took place (still have to put on PPE).
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stevenal
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Post subject: Posted: Thu May 13, 2010 12:43 pm |
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Joined: Tue Jan 13, 2009 5:00 pm Posts: 585
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The ChecVolt is not part of the circuit, it is part of the tester.
1. Test the tester. No problem, test the tester before isolating the circuit.
2. Test the circuit. Checks okay.
3. Test the tester. Reenergize the circuit to test the tester and then proceed to step 1.
See the problem?
You cannot use your non-contact device on a known live circuit to accomplish #3, since both the ChecVolt and the non-contact device must be proved to still be operational.
It doesn't replace regular contact testing, but it could be used to supplement it.
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jghrist
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Post subject: Posted: Sun May 16, 2010 7:35 pm |
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Joined: Wed Jun 04, 2008 9:17 am Posts: 428 Location: Spartanburg, South Carolina
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I agree with stevenal. This is no different conceptually than having a panel meter to verify the voltage.
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TxEngr
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Post subject: Posted: Sat May 29, 2010 8:11 am |
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Joined: Fri Jan 16, 2009 1:07 pm Posts: 67 Location: North Florida
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I believe it meets the requirements. I disagree that it is not a part of the circuit since it is as much of the circuit as the wire going to the top of the CPT. My concern would be the 480V passing over the hinge of the door. I think that the company makes a sleeve (costs extra) that you can run the cable in to avoid damage from abrasion, etc. and this would solve this problem.
Use of this device would also lower the overall exposure to an arc flash incident since you would not have to open the door and be performing contact testing on the hot terminals at the top of the disconnect/breaker. That action is a direct interaction subject to human error and/or equipment failure and much riskier than performing the non-contact measurement through the door.
If I were going to be working on the conductors (e.g. wiring a motor, etc.) I would still perform a check to re-verify, but I tend to do that anyway no matter the test technique.
Just my 2 cents worth.
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