50 Ft. line of sight rule

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Tripwire

Member
Good morning,

I have a similar situation with the "line of sight" rule as another thread was asking about and I need clarification please.

Situation: A Maintenance Mechanic is about to conduct a PM on a conveyor line. He is supposed to lockout two motors. He proceeds to lock out one motor at the motor switch, but fails to lockout the second one because he says that it is quite difficult to reach. Instead, he decides to to lock out the control cabinet that powers both motors among others, but it is more than 50ft away.

The company internal written procedures declare that both motors be disconnected and it doesn't say anything about the control cabinet. The main page of the procedures binder does list ALL the motors that the CC will power down. The Maintenance mechanic did not follow the "letter" of the law, but followed the "spirit" of the law in my opinion.

I think a clarification of the 50 ft rule and whether or not he violated that rule will help me determine is the Mechanic will need to be disciplined.

What are your thoughts? Thank you in advance...
 

Cold Fusion

Senior Member
Location
way north
Good morning,

I have a similar situation with the "line of sight" rule as another thread was asking about and I need clarification please.

Situation: A Maintenance Mechanic is about to conduct a PM on a conveyor line. He is supposed to lockout two motors. He proceeds to lock out one motor at the motor switch, but fails to lockout the second one because he says that it is quite difficult to reach. Instead, he decides to to lock out the control cabinet that powers both motors among others, but it is more than 50ft away.

The company internal written procedures declare that both motors be disconnected and it doesn't say anything about the control cabinet. The main page of the procedures binder does list ALL the motors that the CC will power down. The Maintenance mechanic did not follow the "letter" of the law, but followed the "spirit" of the law in my opinion.

I think a clarification of the 50 ft rule and whether or not he violated that rule will help me determine is the Mechanic will need to be disciplined.

What are your thoughts? Thank you in advance...
You really need to read some of the NEC sections:
My recomendation is:
90.1.C
90.2.A
The NEC covers installation - not operation or maintenance. The only people that violate the 50ft rule are the designers or the installers - not the mechanic pulling service at a later date.

If you really need to look up the NEC issues for the installation:
100.I, In sight From
430.102.A
430.102.B
430.102.B.1
430.102.B.2
430.102.B Exception
430.102.B Exception, FPN 1
These will tell you all about where the disconnects must be located - but not how to use them.

Note that FPN 2 lists a reference to NFPA 70E for information on LOTO procedures. You may wish to read that to see if the LOTO procedure in question meets industry standards.

That being said, I have two comments:
First:
"Instead, he decides to to lock out the control cabinet that powers both motors among others ..." If this is just the control power that's a real problem. Control power lockout is not considered energy isolation. If that is the case, better look at the training the mechanic was given to see if that was made clear.

Second:
This has earmarks of a desk bound, safety wonk that can't be bothered to go look at the installation to see if what the procedure is asking for is reasonable. I hope that isn't you. If the mechanic said it is hard to get to - maybe it is.

cf
 

eric9822

Senior Member
Location
Camarillo, CA
Occupation
Electrical and Instrumentation Tech
My opinion is he did nothing wrong. He isolated the power and applied a LOTO. See 430.102(B). For the most part local disconnects are not required in industrial locations as long as the conditions outlined in the exception are met. Even if they are present there is nothing wrong with isolating upstream or downstream.
 

Tripwire

Member
Thanks guys. I will definitely read the suggested info.

No the rules have been written by others not sure who exactly. Just to make sure I understand the mechanic can lock out the control cabinet which is more than 50 away instead of the motor switch right next to the motor and he is still complying with LOTO regulations correct?
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Thanks guys. I will definitely read the suggested info.

No the rules have been written by others not sure who exactly. Just to make sure I understand the mechanic can lock out the control cabinet which is more than 50 away instead of the motor switch right next to the motor and he is still complying with LOTO regulations correct?

LOTO procedures are established by the employer as part of their required work place safety procedures. The NEC has no jurisdiction for establishing an electrically safe work condition.

You should really be reviewing NFPA 70E in regards to your LOTO procedure. Article 120 of 70E deals with establishing an electrically safe work condition.

Chris
 

mcclary's electrical

Senior Member
Location
VA
Thanks guys. I will definitely read the suggested info.

No the rules have been written by others not sure who exactly. Just to make sure I understand the mechanic can lock out the control cabinet which is more than 50 away instead of the motor switch right next to the motor and he is still complying with LOTO regulations correct?

The "withim sight" keeps him from having tto put a lock on it,,,,except for company policies. If he did install a LO,,,,,then the locked disconnect can be 2 miles away in another building.
 

dbuckley

Senior Member
He proceeds to lock out one motor at the motor switch, but fails to lockout the second one because he says that it is quite difficult to reach.

Is that switch difficult to reach? If so, then whoever placed the second switch should be discplined even more. Sure it's position may be code compliant, but if it is in a difficult to reach place then the installation is inadequate.
 

buldogg

Senior Member
Location
Green Bay, Wisc.
You really need to read some of the NEC sections:
My recomendation is:
90.1.C
90.2.A
The NEC covers installation - not operation or maintenance. The only people that violate the 50ft rule are the designers or the installers - not the mechanic pulling service at a later date.

If you really need to look up the NEC issues for the installation:
100.I, In sight From
430.102.A
430.102.B
430.102.B.1
430.102.B.2
430.102.B Exception
430.102.B Exception, FPN 1
These will tell you all about where the disconnects must be located - but not how to use them.

Note that FPN 2 lists a reference to NFPA 70E for information on LOTO procedures. You may wish to read that to see if the LOTO procedure in question meets industry standards.

That being said, I have two comments:
First:
"Instead, he decides to to lock out the control cabinet that powers both motors among others ..." If this is just the control power that's a real problem. Control power lockout is not considered energy isolation. If that is the case, better look at the training the mechanic was given to see if that was made clear.

Second:
This has earmarks of a desk bound, safety wonk that can't be bothered to go look at the installation to see if what the procedure is asking for is reasonable. I hope that isn't you. If the mechanic said it is hard to get to - maybe it is.

cf

Certain safety lockout systems (such as the Pilz) are recognized as being safe when the control voltage is locked out.
 

Cold Fusion

Senior Member
Location
way north
Certain safety lockout systems (such as the Pilz) are recognized as being safe when the control voltage is locked out.
Didn't know that. And I didn't know these guys made contactors that switched power to say, a 100hp motor. I thought they were mostly plc/sensor mfgs. I knew (or thought I knew) that they made SIL 4 and SIL 5 rated plc systems. But that is an operations issue and is way different than energy isolation for maintenance.

Osha 1910.147 is pretty specific:
osha_1910.147 said:
General -
[URL="http://www.osha.gov/pls/oshaweb/owalink.query_links?src_doc_type=STANDARDS&src_unique_file=1910_0147&src_anchor_name=1910.147(c)(1)"]1910.147(c)(1)[/URL]
Energy control program. The employer shall establish a program consisting of energy control procedures, employee training and periodic inspections to ensure that before any employee performs any servicing or maintenance on a machine or equipment where the unexpected energizing, startup or release of stored energy could occur and cause injury, the machine or equipment shall be isolated from the energy source and rendered inoperative.
1910.147(c)(2)
Lockout/tagout.
1910.147(c)(2)(i)
If an energy isolating device is not capable of being locked out, the employer's energy control program under paragraph (c)(1) of this section shall utilize a tagout system.
1910.147(c)(2)(ii)
If an energy isolating device is capable of being locked out, the employer's energy control program under paragraph (c)(1) of this section shall utilize lockout, unless the employer can demonstrate that the utilization of a tagout system will provide full employee protection as set forth in paragraph (c)(3) of this section.

Energy isolating device. A mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; a disconnect switch; a manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors, and, in addition, no pole can be operated independently; a line valve; a block; and any similar device used to block or isolate energy. Push buttons, selector switches and other control circuit type devices are not energy isolating devices.

However, it's always a good day to learn about new stuff. Would you have any references on using their equipment for energy isolation for pulling maintenance on a conveyor?

cf
 

buldogg

Senior Member
Location
Green Bay, Wisc.
Didn't know that. And I didn't know these guys made contactors that switched power to say, a 100hp motor. I thought they were mostly plc/sensor mfgs. I knew (or thought I knew) that they made SIL 4 and SIL 5 rated plc systems. But that is an operations issue and is way different than energy isolation for maintenance.

Osha 1910.147 is pretty specific:


However, it's always a good day to learn about new stuff. Would you have any references on using their equipment for energy isolation for pulling maintenance on a conveyor?

cf

At the Plant where I work, Pilz systems are used all of the time to disconnect power supplying conveyor lines. With the Pilz system, control voltage is disconnected using a 30A safety disc., which drops out a contactor. The pilz system uses voltage sensors to verify no power is present on the load side of the contactor and then turns on a green light giving the operators a visual indication that lockout is verified.
 

buldogg

Senior Member
Location
Green Bay, Wisc.
Didn't know that. And I didn't know these guys made contactors that switched power to say, a 100hp motor. I thought they were mostly plc/sensor mfgs. I knew (or thought I knew) that they made SIL 4 and SIL 5 rated plc systems. But that is an operations issue and is way different than energy isolation for maintenance.

Osha 1910.147 is pretty specific:


However, it's always a good day to learn about new stuff. Would you have any references on using their equipment for energy isolation for pulling maintenance on a conveyor?

cf

The Pilz system is OSHA approved
 

Cold Fusion

Senior Member
Location
way north
At the Plant where I work, Pilz systems are used all of the time to disconnect power supplying conveyor lines. With the Pilz system, control voltage is disconnected using a 30A safety disc., which drops out a contactor. The pilz system uses voltage sensors to verify no power is present on the load side of the contactor and then turns on a green light giving the operators a visual indication that lockout is verified.

That's pretty neat. I'm a bit surprised that it meets the 1910.147 definition of an energy isolating device.

buldogg said:
The Pilz system is OSHA approved
I didn't know that osha approved anything. How did osha do that? Private ruling? That woul be pretty neat too.

cf
 

buldogg

Senior Member
Location
Green Bay, Wisc.
That's pretty neat. I'm a bit surprised that it meets the 1910.147 definition of an energy isolating device.


I didn't know that osha approved anything. How did osha do that? Private ruling? That woul be pretty neat too.

cf

I'll rephrase that, the Pilz system is acceptable by OSHA for minor servicing but not electrical work.
 

buldogg

Senior Member
Location
Green Bay, Wisc.
That's pretty neat. I'm a bit surprised that it meets the 1910.147 definition of an energy isolating device.


I didn't know that osha approved anything. How did osha do that? Private ruling? That woul be pretty neat too.

cf

The way I understand it, the company I work for received an OSHA letter of interpretation [Interpretation/variance with the energy isolation device requirements
 
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