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 Post subject: Lockout/Tagout practices
PostPosted: Tue Aug 11, 2009 4:36 am 

Joined: Wed Oct 29, 2008 6:05 am
Posts: 39
Is zero voltage verification needed for all lockouts?

Current procedure simplified example
pump change
-Pump is stopped
-Disconnect is opened
-Attempt to start pump from controls
-Lock installed and work performed

Since this lockout does not require any electrical work, do they need to verify that there is zero voltage to the pump motor? This would require a qualified electrical worker to verify.

Thanks in advance!

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PostPosted: Wed Aug 12, 2009 2:09 am 

Joined: Thu Nov 15, 2007 7:58 am
Posts: 33
Location: NY
I believe that all conductors at the work location must be checked dead with the proper rated voltage detection device. In the process of this the person must use the correct "V" rated gloves, and wear all necessary PPE for the environment . That includes arc protection clothing. The only exception is when it is visibly grounded at the work location. If there is an exception for motors, or devices where access to the conductors is a problem, I would like to hear it. Good Question

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PostPosted: Wed Aug 12, 2009 3:36 am 
Sparks Level

Joined: Fri Jan 16, 2009 1:07 pm
Posts: 67
Location: North Florida
Based on my experience, it is not necessary to do a voltage verification for a basic lockout where an electrical hazard will not be present. However, if an electrical hazard is present, then the conductors must be verified as being deenergized to confirm the electrically safe work condition.

I have never particularly liked using the 'bump test' as the measure of a safe lockout even though it is acceptable. My main concern has been the presence of interlocks that could give you a false response to the bump test and then allow startup later. In the 2009 70E some verbage was added stating that drawings must be consulted to confirm that removal of an interlock will not cause sudden startup of the device. In my mind it's a lot easier just to pull the switch and verify an absence of voltage on the load side of the switch. Then it no longer matters what the interlocks are because once the switch is locked out, there is no power available. But many facilities lack enough qualified persons to do this type of verification (e.g. one multicraft mechanic per shift). So if you do the consult drawings thing to confirm interlocks that might create an unsafe condition, the bump test is fine.


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