Locked Cabinets/Rooms as Means to Isolate De-Energized Circuits

[TVH]

Need expertiese on this important subject:

1) Is it permissible to isolate a de-energized electrical circuit by locking out the Distribution Board (DB) ? Open breakers would accompany the closed breaker in the same locked DB. Under what conditions would this be acceptable?

2) Is it permissible to isolate a de-enerized electrical circuit by locking the door of the room that contains the electrical distribution board? If so under what conditions would this be permissible?

Many arguments on pro's and con's of these practices on our consruction site. Appreciate your feedback that is aligned with legal requirements.

TVH

 

[kwired]

I would like to think it is acceptable under certain conditions anyway. Like under initial construction especially, if the main has never been closed and is locked so it can not be closed until all construction is done then why not? For service or maintenance purposes I can see this being a little more complicated though.

 

[GoldDigger]

Where Lock Out / Tag Out is required, especially if several people or crews are working, I do not see that any method that does not either lock an individual breaker or open all the circuits inside the locked panel would be acceptable


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[iwire]

1910.147(d)(4)(i)

Lockout or tagout devices shall be affixed to each energy isolating device by authorized employees.

IMO the above section prohibits applying lockout to a rooms door, to a panel door and to the main in a panel with the intent of applying LOTO to a number of branch circuits.

Doors are not energy isolating devices.

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.

As far as using a main breaker to say, lock out a dozen circuits. In my opinion that does not meat the 'each' part of the section I posted.

 

[SceneryDriver]

IMO the above section prohibits applying lockout to a rooms door, to a panel door and to the main in a panel with the intent of applying LOTO to a number of branch circuits.

Doors are not energy isolating devices.



As far as using a main breaker to say, lock out a dozen circuits. In my opinion that does not meat the 'each' part of the section I posted.

Respectfully disagree: In the instance of a Main breaker tripped (to isolate multiple circuits) and behind a locked door (with appropriate, individual LOTO locks applied to a hasp on the the door), the requirement is met. The Main is tripped; the door is locked; ergo the energy is isolated and incapable to being re-energized until all affected people have removed their LOTO locks. 'Each' is satisfied by "all."

One can parse language until blue in the face. I believe this would meet the spirit of the LOTO regs, which is to ensure worker safety; circuits cannot become energized while being worked on.


SceneryDriver

 

[GoldDigger]

This could be made to work with the right procedures behind it. But it could only be reliable if the only disconnect permitted was at the main breaker level.
But there is still a good argument that although a lock on the door serves to lock out the main breaker, it is not attached to that breaker.
Locking the door to an entire room has too many side effects to be practical. (Unless everything going through that room is shut off.)
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[iwire]

Again I point out that doors on rooms or panelboards are not 'energy isolating devices' and the OSHA standard requires the looks be placed on energy isolating devices.

So forget the door idea, in my opinion that is clearly not an option.

 

[kwired]

Again I point out that doors on rooms or panelboards are not 'energy isolating devices' and the OSHA standard requires the looks be placed on energy isolating devices.

So forget the door idea, in my opinion that is clearly not an option.

I agree, yet not so certain there isn't or couldn't be a little more complexities to this.

Let me ask a couple questions not from NEC perspective but from LOTO perspective.

Can you isolate energy to a branch circuit by locking a feeder or service disconnecting device or do you have to lock the branch circuit itself ?

Can you isolate energy from a compressed air circuit by locking the electrical disconnect for the compressor and then bleeding off the pressure in the system? Or do similar for hydraulic or steam systems? Or do you have to isolate the section you are working on somehow and lock that isolation method so it can not be recharged with pressure until the lock is removed?

 

[GoldDigger]

I
Let me ask a couple questions not from NEC perspective but from LOTO perspective.

Can you isolate energy to a branch circuit by locking a feeder or service disconnecting device or do you have to lock the branch circuit itself ?

Can you isolate energy from a compressed air circuit by locking the electrical disconnect for the compressor and then bleeding off the pressure in the system? Or do similar for hydraulic or steam systems? Or do you have to isolate the section you are working on somehow and lock that isolation method so it can not be recharged with pressure until the lock is removed?

Answering from a position of not looking at OSHA documents:

You can isolate the energy to a branch circuit by locking the feeder off. It may involve a more widespread outage than the operator would prefer though. And you had better be sure that there is not a manual or automatic transfer switch downstream anywhere.

Compressed air: As long as you are secure in your knowledge that none of the other equipment connected elsewhere in the air system contains a storage tank that might dump back into the line, it sounds OK.
Hydraulic: Imagine that you turn off the supply pump but do not bypass the high pressure side back to a reservoir. Now you are working on a piece of equipment when somebody else decides to lower a hydraulic lift or such? Think of utility workers attaching ground jumpers to "disconnected" lines before working on them.
Steam: No comment.

 

[don_resqcapt19]

...
Can you isolate energy from a compressed air circuit by locking the electrical disconnect for the compressor and then bleeding off the pressure in the system? Or do similar for hydraulic or steam systems? Or do you have to isolate the section you are working on somehow and lock that isolation method so it can not be recharged with pressure until the lock is removed?

Most places around here use what they call a "double block and bleed" to isolate air, steam, product lines and things like that. A "double block and bleed" is two lockable block valves in series with a bleed valve between the two block valves.

 

[kwired]

Answering from a position of not looking at OSHA documents:

You can isolate the energy to a branch circuit by locking the feeder off. It may involve a more widespread outage than the operator would prefer though. And you had better be sure that there is not a manual or automatic transfer switch downstream anywhere.

Compressed air: As long as you are secure in your knowledge that none of the other equipment connected elsewhere in the air system contains a storage tank that might dump back into the line, it sounds OK.
Hydraulic: Imagine that you turn off the supply pump but do not bypass the high pressure side back to a reservoir. Now you are working on a piece of equipment when somebody else decides to lower a hydraulic lift or such? Think of utility workers attaching ground jumpers to "disconnected" lines before working on them.
Steam: No comment.

Now we are getting into similar scenario as locking a main breaker or a electrical room door, if you are certain the equipment can not be energized in some other way it is not really any different. IMO LOTO needs to have consistency whether it is electrical energy or other energy that is being locked. NEC has requirements for what qualifies as a disconnecting means in different situations, but that does not necessarily equate to what OSHA requires for LOTO purposes. OSHA may not even have published standards on LOTO IDK, kind of like they don't have electrical safety standards, but rather 70E is popularly adopted as the standard because it is easier to do that than to write your own standard that is as thorough as 70E is.

 

[Jefflubs]

Other Lockable Devices.

Other Lockable Devices.

A Company that I had the pleasure of working with was investigating basically the same plan. The issue they ran into is the door being locked can not have any other item electrical, nuematic, steam or mechanical device in it preventing that item from being shutdown or opened incase of an emergency.