Arc Flash on new buildings
- Thread starter lile001
- Start date
- Status
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Arc Flash on new buildings
When the client (or managing staff) pays I do it. Over the last year for new facilities, I'm 2 for 4 on arc flash and 4 for 4 on short circuit and coordination studies.
When the client (or managing staff) pays I do it. Over the last year for new facilities, I'm 2 for 4 on arc flash and 4 for 4 on short circuit and coordination studies.
lwbrittian
Member
Re: Arc Flash on new buildings
with the increase in use of NFPA 70E, that is requiring flash-blast PPE to be worn, more existing plants are begining to make moves to comply, thus marking and calculations required for PPE. But is the OCP is not maintained-tested and calabrated as recomended by mfg, the afc calculations value can be reduced to worse than none as the may be providing a false sence of secrity.
Lw.
with the increase in use of NFPA 70E, that is requiring flash-blast PPE to be worn, more existing plants are begining to make moves to comply, thus marking and calculations required for PPE. But is the OCP is not maintained-tested and calabrated as recomended by mfg, the afc calculations value can be reduced to worse than none as the may be providing a false sence of secrity.
Lw.
- Location
- Illinois
- Occupation
- retired electrician
Re: Arc Flash on new buildings
I expect that as soon as the professional liability insurance companies find out that it is almost impossible to correctly calculate the incident energy on any system served by an utility, that there will be some very expensive riders for this type of work.
Don
I expect that as soon as the professional liability insurance companies find out that it is almost impossible to correctly calculate the incident energy on any system served by an utility, that there will be some very expensive riders for this type of work.
Don
rcwilson
Senior Member
- Location
- Redmond, WA
Re: Arc Flash on new buildings
We only do it if paid to do it by the client. We always do the short circuit and protection coordination studies.
Our management considers arc flash as part of the safety and operating procedures that are the responsibility of the owner/operator of the facility.
But we are seeing a need for performing the arc flash study anyway, because our construction and commissioning employees are exposed to the hazard.
We only do it if paid to do it by the client. We always do the short circuit and protection coordination studies.
Our management considers arc flash as part of the safety and operating procedures that are the responsibility of the owner/operator of the facility.
But we are seeing a need for performing the arc flash study anyway, because our construction and commissioning employees are exposed to the hazard.
Re: Arc Flash on new buildings
My take on short circuit calculations are that they are *required* by NEC and therefore a necessary part of my scope as a building designer.
Are the arc flash calculations in NFPA 70E *required*? Is 70E adopted by AHJ's, or is it referred to by OSHA and thus required for everybody?
My take on short circuit calculations are that they are *required* by NEC and therefore a necessary part of my scope as a building designer.
Are the arc flash calculations in NFPA 70E *required*? Is 70E adopted by AHJ's, or is it referred to by OSHA and thus required for everybody?
AK_Engineer
Member
Re: Arc Flash on new buildings
lile001
Quick answer;
Qualified NO, NO (AHJ have no J on maintenance or operation personnel), YES.
NEC requires OCP to prevent fires. SCC results are part of electrical equipment design specifications. Arc flash details are not required for design. NEC requires a "generic" arc flash label on equipment.
Worker PPE is required by OSHA.
It is management responsibility to specify PPE requirements for its workers, and to ENSURE they are QUALIFIED to perform the work!
As lwbrittian stated, if "the OCP is not maintained-tested and calibrated as recommended by mfg" then, over time, any arc flash calculation and labeling is compromised.
Short Circuit Calculations, Over Current Protection and Personnel Protective Equipment are critical in preventing injuries to our workers and are the heart of fire prevention!
Remember
NOBODY GETS HURT!
lile001
Quick answer;
Qualified NO, NO (AHJ have no J on maintenance or operation personnel), YES.
NEC requires OCP to prevent fires. SCC results are part of electrical equipment design specifications. Arc flash details are not required for design. NEC requires a "generic" arc flash label on equipment.
Worker PPE is required by OSHA.
It is management responsibility to specify PPE requirements for its workers, and to ENSURE they are QUALIFIED to perform the work!
As lwbrittian stated, if "the OCP is not maintained-tested and calibrated as recommended by mfg" then, over time, any arc flash calculation and labeling is compromised.
Short Circuit Calculations, Over Current Protection and Personnel Protective Equipment are critical in preventing injuries to our workers and are the heart of fire prevention!
Remember
NOBODY GETS HURT!
- Location
- Illinois
- Occupation
- retired electrician
Re: Arc Flash on new buildings
AK_Engineer,
Don
AK_Engineer,
While changes in the OCPDs operation have an effect on the incident energy, the biggest issue is the changes made on the utility side. The utility systems are very dynamic. The available fault current at the line side of the building system changes as the utility makes switching changes in their distribution system. Many utilities will only provide you with the maximum expected fault current at the secondary side of the transformer. While the use of this maximum expected fault current will always result in the selection of equipment suitable for the application, it may result in the selection of PPE that is not suitable for the application. This is because a lower available fault current often results in a higher incident energy and will require a higher level of PPE.
Don
AK_Engineer
Member
Re: Arc Flash on new buildings
don_resqcapt19 has identified the major issue.
Until OCP MFG's have developed ARC signature sensitive OCP devices, we may have to resort to a range of SSC values (max utility and some % of max) then state the worst case result . . .
Modeling software I use follows IEEE 1584. It looks at a 15% reduction in arcing current (mainly for TCC slope effects) and bases the result on the worst case.
Until ARC signature sensitive OCP devices are available the question is "what % of utility max SSC should we use".
I hope IEEE 1584 looks into this . . .
I hope the 2 Chicago Tribune workers injured this last Sunday in an arc flash event recover fully and the "Lineman Culture" committees are successful in their endeavor.
don_resqcapt19 has identified the major issue.
Until OCP MFG's have developed ARC signature sensitive OCP devices, we may have to resort to a range of SSC values (max utility and some % of max) then state the worst case result . . .
Modeling software I use follows IEEE 1584. It looks at a 15% reduction in arcing current (mainly for TCC slope effects) and bases the result on the worst case.
Until ARC signature sensitive OCP devices are available the question is "what % of utility max SSC should we use".
I hope IEEE 1584 looks into this . . .
I hope the 2 Chicago Tribune workers injured this last Sunday in an arc flash event recover fully and the "Lineman Culture" committees are successful in their endeavor.
- Status