Verify-Test-Verify

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stickelec

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The line-side of the Main Breaker on a 480v MCC is rated Dangerous (>40 cal/cm2). How would you comply with verify-test-verify to prove the buss deenergized after opening the Breaker? The MCC is also the source to the lighting transformer for the entire building. Thanks
 
stickelec said:
The line-side of the Main Breaker on a 480v MCC is rated Dangerous (>40 cal/cm2). How would you comply with verify-test-verify to prove the buss deenergized after opening the Breaker? The MCC is also the source to the lighting transformer for the entire building. Thanks
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We use a non-contact voltage detector mounted on a hot stick.
Our implementation of allowable risk assessment lets us wear 'Category 4' PPE to remove covers on equipment that we are extremely confident is de-energized in order to verify its actual state. Remember, 'we are trained professionals, do not try this at home', this is part my company's safe work practices policy that has been cleared through our 'risk management' group.
 
stickelec said:
The line-side of the Main Breaker on a 480v MCC is rated Dangerous (>40 cal/cm2). How would you comply with verify-test-verify to prove the buss deenergized after opening the Breaker? The MCC is also the source to the lighting transformer for the entire building. Thanks
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Difficult question to answer that comes up often, I am of the same school as Jim Dungar but opinions vary on this matter. One thing to keep in mind is the assumed working distance your label lists compared to the length of your hotstick, the actual Ei can be much less.
 
The Graceport product appears to be a quality device but it does leave room for doubt because it can't be verified. It might work in a redundant scheme where it is not the sole method used, or possibly for "mechanical LOTO" rather than electrical. For example, if a mechanic is going to change oil in a compressor.

Our program has not allowed us thus far to use non-contact voltage detectors as the sole means to prove deenergized (for electrical work). I can see where the models that have a self-test feature could satisfy the requirement (ie: Amprobe TIC-300PRO). Even then I would feel better using it in conjunction with a volt-meter before I put my hands on an exposed terminal.

Jim, I appreciate your comment and disclaimer about you and your group being professionals, but we have to remember that there are many more out there that are "less than fully developed professionals" that are doing this work everyday. It would be nice to have such a qualified professional available to every tech in the field to prove his gear deenergized before he makes contact, but when the assets cover 7 states that's not possible. I'm trying to help develop a program to be sure these people are properly trained and have the necessary equipment, and at the same time maintain some resemblance of continued operations.

BTW: I won't try it at home - I sold my MCC. :D
 
stickelec said:
I'm trying to help develop a program to be sure these people are properly trained and have the necessary equipment...
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As soon as you have done that you will be able to have 'professionals' that can perform work per your Electrical Safe Work Practices.

The important thing is to understand that NFPA 70E is purposely written 'vaguely' when it comes to the 'how to'. It is your company's responsibility to protect your workers from the hazards they experience when working on or near electrical equipment.

My non-contact voltage detector is not a simple 'tic' device. We use a self testing device, Model 4744 from Salisbury.
 
The Amprobe TIC-300PRO has the self-test feature also. Our guys are very much professionals but not to the level of a EE - although we all are still learning, especially in the light of the requirements of 70E.

I would appreciate it if anyone would comment on the temporary grounding and how they apply it (typical 480v MCC). Thanks
 
stickelec said:
Our guys are very much professionals but not to the level of a EE - although we all are still learning, especially in the light of the requirements of 70E.
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I am a qualified electrical worker in the eyes of my company because they have trained me, not because of my schooling. As soon as I leave this company, I will need to be re-qualified by my new company under their practices.

In general, we do not apply safety grounds at 480V.
 
jim dungar said:
I am a qualified electrical worker in the eyes of my company because they have trained me, not because of my schooling. As soon as I leave this company, I will need to be re-qualified by my new company under their practices.

In general, we do not apply safety grounds at 480V.
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Well said. That is the exact goal we are striving to accomplish with the development of our program. Thanks
 
zog said:
How do you know if the voltage is off or if the device failed? You still would need to do a L-D-L verification to comply with 70E.
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Because you see it illuminated before you operate the disconnect. You have dual LEDs in each phase to protect against individual LED failure. To have EVERY individual LED fail simultaneously as you're switching off is HIGHLY improbable.
 
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