Arc Flash Calculation and Labeling Responsibility?

[rupej]

Hello,

I work for a small business that builds control panels, usually designed for a 480VAC feed. The question of arc flash calculation and labeling has come up, and my understanding is that it is the site owner's responsibility for the calculation and labeling. The reason being that we have no way of knowing what transformer/circuit breaker it will be connected to in the field, and thus cannot calculate the available fault current. I've combed through NFPA 70E, and can't find where that responsibility is clearly spelled out.

Am I correct that it is the site owner's responsibility for arc flash labeling?

Thanks!

 

[zog]

You are correct but I believe you have to put a generic arc flash hazard label per the NEC on the panel. System owner would be the one responsible for the calcs and detailed label.

 

[goodcode]

NEC/70E

NEC/70E

This is a very common misunderstanding. The only "installation requirement" is the generic arc flash hazard warning mandated in 110.16 which can be "field or factory marked."

Labeling of equipment with an incident energy (IE) level or an arc flash PPE category level is not an installation requirement. There is no requirement for any manufacturer or installer to apply such a label. There is no requirement that an inspector can cite to require such a label.

While the NEC and 70E both address electrical safety, they are dynamically different. The NEC (70) addresses installation requirements and 70E addresses electrical safe work practices. 70E cannot and does not contain any installation requirements. In fact, Chapter 3 of 70E was recently overhauled to remove many installation requirements.

The NEC and 70E are consensus documents. They can only become enforceable where they are adopted by a local municipality, city or state. The NEC is adopted in this manner but 70E is not.

There are many individuals that think 70E is an enforceable document because the style is similar to the NEC and it uses terms such as "shall or shall not." 70E is a standard, not a code. Read how NFPA defines those terms and you will see that a standard is designed to be adopted by other codes or referenced in regulations.

There are requirements that employers are legally bound to comply with but they are federal regulations as seen for example in OSHA 1926 and 1910. There are requirements in the OSHA standards that are reflected in 70E. In those cases, the reality is that OSHA is the shall, 70E just shows the employer how. It must be understood that 70E has requirements that OSHA does not, meaning there are no federal regulations that an employer must follow.

A close read of 130.5(D) in 70E 2015 reveals that after all of the parent text the last paragraph states that the installation, documentation and maintenance of the label is the responsibility of the owner of the electrical equipment. This text intentionally removes the installer from any such requirement. The bottom line is that labeling is optional and is at the whim of an owner. There is no federal regulation in OSHA 1926 or 1910 that requires labeling.

There are many blogs, articles and discussions about required labeling. It is all much ado about nothing because there is no requirement. It is simply an option of the owner.

There is a second revision in 110.16 for the 2017 NEC that requires labeling of service equipment rated 1200 amps or more. If it survives the process, the 2017 edition of the NEC will be the first to require such labeling and will be limited to services rated 1200 amps or more.

 

[big john]

The only caveat I will add is that if an employee should be injured performing allowable hot-work then woe betide the equipment owner for not having incident energy calculations on that gear.

Labeling may not always be technically required, but that pretty much makes it so the gear can only be touched in a zero energy state.

 

[cowboyjwc]

This is a very common misunderstanding. The only "installation requirement" is the generic arc flash hazard warning mandated in 110.16 which can be "field or factory marked."

Labeling of equipment with an incident energy (IE) level or an arc flash PPE category level is not an installation requirement. There is no requirement for any manufacturer or installer to apply such a label. There is no requirement that an inspector can cite to require such a label.

While the NEC and 70E both address electrical safety, they are dynamically different. The NEC (70) addresses installation requirements and 70E addresses electrical safe work practices. 70E cannot and does not contain any installation requirements. In fact, Chapter 3 of 70E was recently overhauled to remove many installation requirements.

The NEC and 70E are consensus documents. They can only become enforceable where they are adopted by a local municipality, city or state. The NEC is adopted in this manner but 70E is not.

There are many individuals that think 70E is an enforceable document because the style is similar to the NEC and it uses terms such as "shall or shall not." 70E is a standard, not a code. Read how NFPA defines those terms and you will see that a standard is designed to be adopted by other codes or referenced in regulations.

There are requirements that employers are legally bound to comply with but they are federal regulations as seen for example in OSHA 1926 and 1910. There are requirements in the OSHA standards that are reflected in 70E. In those cases, the reality is that OSHA is the shall, 70E just shows the employer how. It must be understood that 70E has requirements that OSHA does not, meaning there are no federal regulations that an employer must follow.

A close read of 130.5(D) in 70E 2015 reveals that after all of the parent text the last paragraph states that the installation, documentation and maintenance of the label is the responsibility of the owner of the electrical equipment. This text intentionally removes the installer from any such requirement. The bottom line is that labeling is optional and is at the whim of an owner. There is no federal regulation in OSHA 1926 or 1910 that requires labeling.

There are many blogs, articles and discussions about required labeling. It is all much ado about nothing because there is no requirement. It is simply an option of the owner.

There is a second revision in 110.16 for the 2017 NEC that requires labeling of service equipment rated 1200 amps or more. If it survives the process, the 2017 edition of the NEC will be the first to require such labeling and will be limited to services rated 1200 amps or more.

110.24 Available Fault Current. (A)Field Marking. Service equipment in other than dwelling units shall be legibly marked in the field with the maximum available fault current. The field marking(s) shall include the date the fault current calculation was performed and be of sufficient durability to withstand the environment involved.

 

[raider1]

110.24 Available Fault Current. (A)Field Marking. Service equipment in other than dwelling units shall be legibly marked in the field with the maximum available fault current. The field marking(s) shall include the date the fault current calculation was performed and be of sufficient durability to withstand the environment involved.

Take a look at the Informational note to 110.24(A)

Informational Note: The available fault-current marking(s) addressed in 110.24 is related to required shortcircuit current ratings of equipment. NFPA 70E-2012, Standard for Electrical Safety in the Workplace, providesassistance in determining the severity of potential exposure,planning safe work practices, and selecting personal protective equipment.

The available fault current marking in 110.24(A) is related to short circuit current ratings of equipment and aic rating of overcurrent protective devices and is not related to NFPA 70E. While available fault current is used in the incident energy calculations the infinite buss method that is commonly used to come up with the available fault current calculations to verify compliance with 110.9 and 110.10 is not used for incident energy calculations.

Chris

 

[cowboyjwc]

Take a look at the Informational note to 110.24(A)



The available fault current marking in 110.24(A) is related to short circuit current ratings of equipment and aic rating of overcurrent protective devices and is not related to NFPA 70E. While available fault current is used in the incident energy calculations the infinite buss method that is commonly used to come up with the available fault current calculations to verify compliance with 110.9 and 110.10 is not used for incident energy calculations.

Chris

2011 doesn't have an informational note.

 

[raider1]

2011 doesn't have an informational note.

Correct,

The Informational Note was added in the 2014 NEC to address the issues raised by people engaged in incident energy calculations and what the marking in 110.24(A) was intended to address.

Chris

 

[cowboyjwc]

Correct,

The Informational Note was added in the 2014 NEC to address the issues raised by people engaged in incident energy calculations and what the marking in 110.24(A) was intended to address.

Chris

And when we adopt the 2014, I won't make the engineers do the calculation anymore.

 

[raider1]

And when we adopt the 2014, I won't make the engineers do the calculation anymore.

John, I think you may be confusing Arc Flash Calculations and Available Fault current calculations.

The original poster is addressing arc flash calculation and labeling, goodcode pointed out that there is nothing in the NEC that mandates that a company label equipment with incident energy calculations.

110.24(A) requires service equipment to be labeled with the available fault current and the date the calculation was performed. Again this requirement has nothing to do with Arc Flash Calculations and is intended to help with the requirements in 110.9 and 110.10 for short circuit current ratings and AIC ratings of equipment. That is the reason that the 2014 NEC has an informational note to clarify this point.

When you adopt the 2014 NEC the engineers would still be required to do an available fault current calculation to verify compliance with 110.9 and 110.10.

Chris

 

[cowboyjwc]

Ok, now I understand what you are talking about. While it may not be required it's still important. If you don't know the answer how do you know what level of PPE is required?

 

[GoldDigger]

Ok, now I understand what you are talking about. While it may not be required it's still important. If you don't know the answer how do you know what level of PPE is required?

It is important to know that, yes. But that information cannot come from the manufacturer. It requires calculations involving field conditions.

 

[raider1]

Ok, now I understand what you are talking about. While it may not be required it's still important. If you don't know the answer how do you know what level of PPE is required?

Yes, Incident calculations are important in selecting the proper PPE, but NFPA 70E allows the use of task specific tables to be used to select the proper PPE. These tables do not require a full incident energy calculation but rely on the user to know the available fault current and the clearing times of the upstream overcurrent protective devices to know if they can use the Tables.

Chris

 

[GoldDigger]

Yes, Incident calculations are important in selecting the proper PPE, but NFPA 70E allows the use of task specific tables to be used to select the proper PPE. These tables do not require a full incident energy calculation but rely on the user to know the available fault current and the clearing times of the upstream overcurrent protective devices to know if they can use the Tables.

Chris

But if you go beyond knowing the clearing time and the maximum fault current and you actually out them together into an incident energy calculation, then you are no longer allowed to use the tables.

 

[cowboyjwc]

It is important to know that, yes. But that information cannot come from the manufacturer. It requires calculations involving field conditions.

That's what I was saying, but Chris and I were talking about different things.