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 Post subject: Doors closed
PostPosted: Wed Aug 27, 2008 5:57 am 
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(Reposted from feed blitz)

A recent article in the NFPA Journal discusses the thorny question of whether, and in what circumstances, personal protective equipment should be worn when there are no live, exposed electrical parts. Technically, when there are no exposed parts, there is no flash protection boundary—but there may still be a risk of injury. Equipment doors can be blown open and panels blown off by an arc flash explosion, and hot gases can escape through louvers or cracks and cause burns.

In a facility using the PPE tables provided in NFPA 70E, there are a few instances where PPE is required even though no live parts are exposed. For instance, Table 130.7(C)(9)(a) lists the required PPE for "Circuit breaker (CB) or fused switch operation with doors closed" as hazard/risk category 2. However, even for facilities which do not rely on the NFPA 70E tables, safety-consciousness will often suggest wearing more PPE than is explicitly required.

In the 2009 edition of NFPA 70E, a new fine-print note will be added, which will state in part, The collective experience of the task group is that in most cases closed doors do not provide enough protection to eliminate the need for PPE for instances where the state of the equipment is known to readily change, i.e. doors open or closed, rack in or rack out.

While a fine-print note is not a formal requirement, arc flash safety isn't about following the letter of the law. True safety consciousness requires taking appropriate steps to minimize all hazards—and wearing PPE is often one of those steps.


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PostPosted: Wed Aug 27, 2008 5:24 pm 
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I am going to raise this in my NFPA Comment thread.

I personally think this is ridiculous. We should not trying to eliminate every accident, if that is the goal, close the factory now and have the chinese take the risks. This reg is going to upset a lot of business owners.

I wonder how many members have a financial tie to the FR clothing industry.


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PostPosted: Fri Sep 05, 2008 8:12 am 
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I've run across this thorny question several times at customer's flacilities. As example: In many cases production workers have to operate 480 volt equipment disconnects for LOTO and simply turning on the equipment at the start of a shift. It the panel doors are closed no PPE is required but under the proposed changes it will be required. Employers aren't going to buy or make a production works, classified as "not electrical qualified" to don FR PPE every time a closed panel disconnect is operated or calling in a electrican for premimum money on off shifts to flip a disconnect. I agree with Haze10...


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PostPosted: Fri Sep 05, 2008 8:28 am 
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This question has come up in facilities I work in also. To turn on the HID light in the soreroom the storekeeper is required to actually close the circuit breaker, this is also happening in some of our general office areas. Definitely not a good practice and no longer even being considered but is it meant for us to go to every one of these areas and install switches in the circuit? It would be difficult for me to propose having FR clothing hanging on a rack by the panelboard for the office worker to put on before starting work.


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PostPosted: Fri Sep 05, 2008 10:05 am 
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JoeP

The most important thing to address here is common sense and reality.
These points are made clear by MIEnineer, Geh, & Haze that cetain situations should not require PPE.
The common sense of it is what a reasonable qualified person would consider a situation as a possible arcflash situation.
The rule should be more generalized by stating something similar to " behind closed doors if an archflash would present possible injury or such.


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PostPosted: Fri Sep 05, 2008 8:41 pm 
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I have resposded to dozens of switchgear faults with the doors closed that blew apart the gear, blew open doors, etc. No one ever made any promises about switchgear containing an arc blast, thats why the 70E tables have PPE requirements for operating equipment with the doors closed.

geh7752, Who says no PPE is required to operate a 480 breaker or switch with the covers on? You need PPE in most cases, and what does "electrically qualified" mean? 70E isnt just for electrical workers, in fact the word "Electrician" is no where to be found in the 70E.


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PostPosted: Fri Sep 05, 2008 9:10 pm 
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If the concept is restricted to just switchgear, then I don't have a problem with it, and I think we need to limit it to drawout breakers. But absolutely not if we are talking MCC Buckets, disconnect, molded case breakers, etc. I've been involved with ARc Flash analysis in 4 manufacturing complexes, and we discussed this. They all stated they would not conform to this portion as they don't see the risk and it would be too much of a hardship to the manufacturing process.


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PostPosted: Sat Sep 06, 2008 6:40 am 
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haze10 wrote:
If the concept is restricted to just switchgear, then I don't have a problem with it, and I think we need to limit it to drawout breakers. But absolutely not if we are talking MCC Buckets, disconnect, molded case breakers, etc. I've been involved with ARc Flash analysis in 4 manufacturing complexes, and we discussed this. They all stated they would not conform to this portion as they don't see the risk and it would be too much of a hardship to the manufacturing process.


I agree, the line needs to be drawn somewhere for the PPE requirements with the doors closed, I would include MCC's myself btu otherwise agree with you.

However, I do not think any power distribution equipment should be operated by untrained (Unqualified) personel, they dont need to be electrical gurus, just know the construction and operation of the equipment they are expected to operate and the hazards associated with that task.


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PostPosted: Sat Sep 06, 2008 7:48 am 
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Electrician is found here

Zog wrote:
I have resposded to dozens of switchgear faults with the doors closed that blew apart the gear, blew open doors, etc. No one ever made any promises about switchgear containing an arc blast, thats why the 70E tables have PPE requirements for operating equipment with the doors closed.

geh7752, Who says no PPE is required to operate a 480 breaker or switch with the covers on? You need PPE in most cases, and what does "electrically qualified" mean? 70E isnt just for electrical workers, in fact the word "Electrician" is no where to be found in the 70E.


Lockout/Tagout Devices Applied.
Each employer shall identify, document, and implement lockout/tagout procedures
conforming to Article 120 to safeguard employees from exposure to electrical hazards. The
lockout/tagout procedure shall be appropriate for the experience and training of the
employees and conditions as they exist in the workplace.
(A) General. All electrical circuit conductors and circuit parts shall not be considered to be
in an electrically safe work condition until all of the applicable requirements of Article 120
have been met.
FPN: See 120.1 for the six-step procedure to verify an electrically safe work condition.
(B) Principles of Lockout/Tagout Execution.
(1) Employee Involvement. Each person who could be exposed directly or indirectly to a
source of electrical energy shall be involved in the lockout/tagout process.
FPN: An example of direct exposure is the qualified [SIZE="3"]electrician [/size]who works on the motor starter control,
the power circuits, or the motor. An example of indirect exposure is the person who works on the
coupling between the motor and compressor


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PostPosted: Sat Sep 06, 2008 8:41 am 
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JoePenachio wrote:
The most important thing to address here is common sense and reality.


This stuff is confusing enough and now you want to bring common sense and reality into it? :D


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PostPosted: Sat Sep 06, 2008 3:58 pm 
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JoeTedesco wrote:
Lockout/Tagout Devices Applied.
Each employer shall identify, document, and implement lockout/tagout procedures
conforming to Article 120 to safeguard employees from exposure to electrical hazards. The
lockout/tagout procedure shall be appropriate for the experience and training of the
employees and conditions as they exist in the workplace.
(A) General. All electrical circuit conductors and circuit parts shall not be considered to be
in an electrically safe work condition until all of the applicable requirements of Article 120
have been met.
FPN: See 120.1 for the six-step procedure to verify an electrically safe work condition.
(B) Principles of Lockout/Tagout Execution.
(1) Employee Involvement. Each person who could be exposed directly or indirectly to a
source of electrical energy shall be involved in the lockout/tagout process.
FPN: An example of direct exposure is the qualified [SIZE="3"]electrician [/size]who works on the motor starter control,
the power circuits, or the motor. An example of indirect exposure is the person who works on the
coupling between the motor and compressor


That is just an example, not part of the standard, and anyways I was refering to the qualification requirements in my post and that was the intent, 70E qualification has nothing to do with being an electrician or not.


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PostPosted: Sat Sep 06, 2008 6:22 pm 
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Only a very limited percentage, may 5%, of lockouts are for exposure to live electrical components. An electrician who is sent to change a failed motor for example. The vast majority of lockouts are for general equipment maintenance with the lockout being to protect the worker from 'other' forms of energy. Example, work on pipe systems require you to lockout the supply pump, work on a gearbox requires you to lockout the motor, work on air compressor, lockout the motor, etc , etc, etc.

This is why there is such a wide and diverse group of people who operate MCC buckets and single disconnects, and why it would be such an unnecessary hardship to include them in FR. They are also relatively low energy because they are almost always connected to the high energy bus with short wires sized to the load. MCC buckets are no worse than other distribution devices, and in most manufacturing constitutes the vast majority of lockouts.


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PostPosted: Sun Sep 07, 2008 4:42 am 
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Let me get this straight.

I understand racking a breaker could be dangerous but now you need to wear PPE to open / close a switch, mcc etc. that was designed to operate safely??!!? Is this implying that NEMA and other equipment design standards are not sufficient for the design of safe equipment? Now we must assume that properly designed equipment WILL FAIL and injure or kill us?

Do I now have to worry about tires falling off of my car because even though it is suppose to be designed correctly, there is a REMOTE possibility it could happen?

Who comes up with this stuff? Have they ever worked in the real world? No wonder our manufacturing is going to China!


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PostPosted: Mon Sep 08, 2008 6:57 am 
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A couple of points:

1) A FPN is not enforceable, and so can be ignored strickly from a "following the code" mentality. They are meant to clarify other statements in the code.

2) The H/R Category for operating breakers or switches with covers on is 0 in the case of panelboards, MCCs, and switchgear, 600V or less. So if you are using the tables, you should only have to worry about all cotton clothing anyway, and it is not necessary to hang a flash suit next to the equipment to be operated. I don't think that all cotton (or silk, if you loved the 80's) clothing is unreasonable for people who will be operating disconnects. Make it part of the training to verify someone is qualified to operate the equipment.


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PostPosted: Mon Sep 08, 2008 7:04 am 
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WDeanN wrote:
A couple of points:

1) A FPN is not enforceable, and so can be ignored strickly from a "following the code" mentality. They are meant to clarify other statements in the code.

2) The H/R Category for operating breakers or switches with covers on is 0 in the case of panelboards, MCCs, and switchgear, 600V or less. So if you are using the tables, you should only have to worry about all cotton clothing anyway, and it is not necessary to hang a flash suit next to the equipment to be operated. I don't think that all cotton (or silk, if you loved the 80's) clothing is unreasonable for people who will be operating disconnects. Make it part of the training to verify someone is qualified to operate the equipment.



True about the FPN, just claryfing that the term is used in 70E, see post #6

"in fact the word "Electrician" is no where to be found in the 70E"


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PostPosted: Wed Sep 10, 2008 6:41 am 
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Zog wrote:
I have resposded to dozens of switchgear faults with the doors closed that blew apart the gear, blew open doors, etc. No one ever made any promises about switchgear containing an arc blast, thats why the 70E tables have PPE requirements for operating equipment with the doors closed.

geh7752, Who says no PPE is required to operate a 480 breaker or switch with the covers on? You need PPE in most cases, and what does "electrically qualified" mean? 70E isnt just for electrical workers, in fact the word "Electrician" is no where to be found in the 70E.



Zog: I stand corrected on the term "electrically qualified"... it was a mis-statement. Under table 130.7(C)(9)(A) operating MCC and 600V Class Switchgear with doors closed is HRC 0. under "Notes 3 & 6" the HRC can be reduced one level if the Isc is <10kA or <25kA respectively. Therefore, as example, a local 480 volt, 3 phase machine disconnect being fed with 20 feet of bus drop 3c/#6 awg (65 amp fla) with a calculated Isc of 4kA at the disconnect, can be classified as HRC -1. Short sleeeve shirt, long pants. Or a molded case breaker 480 V, 250 amp rating with a bus terminal connection Isc of 21kA is HRC -1.


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PostPosted: Wed Sep 10, 2008 6:51 am 
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geh7752 wrote:
Zog: I stand corrected on the term "electrically qualified"... it was a mis-statement. Under table 130.7(C)(9)(A) operating MCC and 600V Class Switchgear with doors closed is HRC 0. under "Notes 3 & 6" the HRC can be reduced one level if the Isc is <10kA or <25kA respectively. Therefore, as example, a local 480 volt, 3 phase machine disconnect being fed with 20 feet of bus drop 3c/#6 awg (65 amp fla) with a calculated Isc of 4kA at the disconnect, can be classified as HRC -1. Short sleeeve shirt, long pants. Or a molded case breaker 480 V, 250 amp rating with a bus terminal connection Isc of 21kA is HRC -1.


True, but those notes are being removed in the 2009 70E


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PostPosted: Wed Sep 10, 2008 7:52 am 
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Zog wrote:
True, but those notes are being removed in the 2009 70E


I know the notes are being remove in 2009. Until the 2009 edition is out it's still valid. I don't get into -1 HRC with customers because it opens a can of worms.


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PostPosted: Wed Sep 10, 2008 9:34 am 
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geh7752 wrote:
I know the notes are being remove in 2009. Until the 2009 edition is out it's still valid. I don't get into -1 HRC with customers because it opens a can of worms.


It is being removed because it isnt safe, so even though technically it is not valid someone can still get hurt. I also avoid the topic with customers, like you said, whole can of worms I dont want to open.


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PostPosted: Mon Nov 17, 2008 10:29 am 
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I feel it is time for the equipment manufacturers to speak to this. We've seen videos of equipment blowing apart in an effort to sell arc resistant gear, but the failed equipment videos fail to specify whether the gear was operated within design rating etc.

It would seem the manufacturer's reputation to contain a fault (within specification) would be important, and yet they probably are reluctant to publish thisfor liabiilty concerns.


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