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 Post subject: Lockingout motor
PostPosted: Tue May 25, 2010 1:12 am 

Joined: Sun Nov 16, 2008 12:01 pm
Posts: 44
My company insist that when lockingout a piece of equipment like a motor it must be done at the mcc or panel and not at a disconnect located at the motor or piece of equipment. Is there a right location and a wrong location as far as 70e and osha is concern ?


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PostPosted: Tue May 25, 2010 4:42 am 
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Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
PUCKMAN wrote:
My company insist that when lockingout a piece of equipment like a motor it must be done at the mcc or panel and not at a disconnect located at the motor or piece of equipment. Is there a right location and a wrong location as far as 70e and osha is concern ?


You're more likely to lockout the wrong equipment when at the MCC then at 10' from it.
Plus you get to watch if somebody messes with your lockout.


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PostPosted: Wed May 26, 2010 9:37 am 
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Joined: Sat Jun 07, 2008 5:11 pm
Posts: 143
Location: Connecticut
Locking out only the motor t-leads is dangerous. If someone energizes the motor starter circuit in the mcc, the motor will rotate as soon as the local disconnect is closed. This is a uncontrolled start (we call them hot starts) and could result in equipment damage or personnel injury. Most equipment is PLC controlled nowadays with aux contacts in the starters to let the PLC logic know it energized. So locking out only at the motor could result in the PLC starting other equipment that "thought" this motor was running. Our policy is LOTO at the MCC then test by using the start button to verify the device in question won't start. Only the person locking out the device can unlock it and each person's locks only have one key. Anyone "messing" with someone's LOTO lock is terminated no questions asked.


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PostPosted: Sat May 29, 2010 9:03 am 
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Joined: Fri Jan 16, 2009 1:07 pm
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Location: North Florida
I have installed local disconnects at motor locations many times. Typically this is done where maintenance will need to lockout to perform work, then rotate the equipment for testing, the immediately re-lock for adjustment.

I always purchase disconnects with auxiliary contacts that are fed back to the starter bucket so that if the switch is de-energized, the control circuits will not energize. Since these are make-before-break contacts this will also drop out a running motor before the disconnect is opened, a nice safety feature although our training requires stopping of the motor prior to use of disconnect. This avoids the problem that geh7752 noted. This should be a standard. I also purchase disconnects with the viewing window and that have the positive indication when the blades are out of the stabs. As part of our training for mechanics or operators that will use the disconnects, they are taught how to visually verify that the disconnect opened all three phases. We don’t use the “within sight rule” in these installations and everyone has to apply a lock if working on the equipment.


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