ABOUT THE IEEE 1584-2003?? 2

[nostromo332003]

HI
I´m began with the study of arc flasing, but need information about the ieee 1584-2002 and NFPA 70C

someone could help with that documents (if send me the ieee 1584-2002 i will be very happy) or any information about this topic (arc flasing)??

best regards

 

[dpc]

You will need to purchase both of the standards. They are not available for free. I believe you want NFPA-70E, not 70C. It is relatively inexpensive, about $65 or so. IEEE-1584 will be much more expensive.

You might start with this link to get more info on arc-flash.

http://www.easypower.com/arcflash_resource.html

I'm sure a Google search will give you many other options.

 

[nostromo332003]

thanks

I download the easy power guide of arc flasing but i have some question about this :

1 whats is it means this standars?? i know this calculate the power of short circuit and you give a warning to the personal that is all??

2 when this studied do you do??? do you do in all short circuit calculate in low voltage?? or in special case??


well thanks a lot

 

[mpparent]

The IEEE standard as well as NFPA 70E gives the engineer a way to calculate the arc flash hazard at a particular point in an electrical distribution system. Once you know the hazard, then you can wear the appropriate PPE (personal protective equipment), so that one can survive an event if it happened. It also may tell you that you cannot work a specific task, and you must shutdown your equipment to perform maintenance for example.

Mike

 

[mykh]

Both IEEE 1584 and NFPA 70E provide with procedures for performing arcflash analysis and hazard risk assessment. This are required to determine the appropriate personnel protective equipment for work near any exposed electrical conductor or circuit part. Check

http://www.arcadvisor.com

for IEEE1584 and NFPA70E based online calculators

Michael

 

[nostromo332003]

thanks

i check the program of arcadvisor anh it is very interesting but i have more question about this topic:

sometimes in the shorcircuit study in low voltage( 480 v, 208 v) the level of ampacity in the ground fault is biggest than the 3 phases fault ( when the system hasn´t motor) i will take the ground fault for the arc flasing study?

regard

 

[dpc]

Per IEEE-1584-2002, you only need to consider the three-phase bolted fault current as the basis for determining the arcing current.

 

[RRaghunath]

Thanks mpparent, for the informative post on arc flash hazard.
I am in power plant engineering for many years but have never heard about the calculations and IEEE/NFPA requirements for arc flash hazard estimations.

How old are these requirements in the said codes.

It is NFPA means, the stimation should be mandatory, right.

Thanks once again.

 

[dpc]

NFPA-70E is a consensus standard - it is not mandatory in the way that the NEC or fire codes are mandatory.

However, OSHA compliance is mandatory and OSHA has made it clear that they consider arcing faults a workplace hazard and that employers must provide adequate assessment of the risk and protection against the hazard.

Compliance with NFPA-70E will satisfy OSHA.

If your facility hasn't developed an arc-flash protection plan yet, you will be doing one in the not-too-distant future - that's my prediction

 

[mpparent]

Like dpc says, it isn't mandatory, but like him, I believe it will be an integral part of NFPA 70 and could possibly reference OSHA requirements and vise versa.

Mike

I believe even in the 2005 NFPA (correct me if I'm wrong guys), that the section on arc flash is still in the appendix. So it's recommended but on apart of the code yet.

 

[RRaghunath]

Thanks dpc and mpparent for the insight. It is interesting / useful.

 

[alehman]

As of 2002, the NEC (aka NFPA 70) requires non-specific arc flash hazard warning signage.

http://www.goodmart.com/products/229295.htm

There has been discussion of adding a requirement for the signage to indicate the exact hazard level. That would require a detailed arc flash study. So far that hasn't happened.

The NEC only specifies installation practice. NFPA 70E specifies safe work practices. Like any NFPA code, it can be adopted by local authorities if they choose. I don't know of any that have. I've heard tell of some U.S. OSHA authorities enforcing it however. Many organizations are beginning to use 70E by choice in their facilities.

http://www.reliabilityweb.com/art05/nfpa_70e.htm

 

[MCCdork]

The following article from the March 2005 Consulting/Specifying Engineer magazine states that OSHA has already adopted NFPA 70E as its standard for arc flash protection:

http://www.csemag.com/article/CA510522.html?nid=2072&rid=324273227

Some power system analysis software vendors offer arc flash plug-in modules for their modeling programs. That's very handy because you can do your system coordination and arc flash studies together. Some will even calculate the required protective clothing and print warning labels to place on the field equipment.

Like dpc said above, if you haven't done arc flash studies for your facility or clients, you will...and very soon.

 

[alehman]

I'm not sure that article is accurate. That's the first I've heard that OSHA actually adopted 70E. Last year OSHA was consiering adopting only Part 1 of 70E, which covers installation practice. Part 2 covers safe work practices and so far as I know, wasn't being considered as late as last year. See this discussion:

http://groups-beta.google.com/group...4b551ebf4a1e/47e08b732bfbc782?q=nfpa+70e+osha

This article promulgates the myth that fuses provide better arc flash protection than circuit breakers. That's partially true for very high fault current. If the fault doesn't exceed the current limiting threshold of the fuse, typical circuit breakers are usually faster - sometimes much faster. Bussmann's arc flash tool will verify this:

for a 10kA fault,
exposure for a 600A LPS fuse = 12.83 cal/cm^2 (triple this for a 3-phase fault)
exposure for a 600A MCCB = 1.44 cal/cm^2

 

[dpc]

I haven't read the article referenced, but if OSHA had actually adopted NFPA-70E-2004, I'm pretty sure I would have heard about it. OSHA is reluctant to do this type of wholesale adoption because of the way the standard is worded and because of the frequent updates to the standard.

OSHA does use NFPA-70E for training their compliance officers and OSHA officials have said that compliance with NFPA-70E will satisfy OSHA requirements regarding electrical safety.

But, I do not believe use of NFPA-70E is mandated by OSHA. It is possible that a company could have an in-house safety plan that OSHA would accept in place of NFPA-70E. I would say that very few workplaces comply with all facets of NFPA-70E-2004.

 

[mpparent]

To solidify dpc's point, the IEEE has received funding to further study arc flash phenomenon. If you look at the existing standard, and look at some of the numbers the equations spit out...they still have some work to do, in my humble opinion.

Mike

 

[IASMike]

I have read a couple OSHA inspection reports where companies were sighted for no arc-flash protection. In one report OSHA recommended NFPA-70E and in another they just said you must provide arc-flash protection.
From what I have read I believe as long as you provide adequate protection for you employees OSHA will not say to much. But I believe the trend is going to be towards at the very least more labeling of what hazards exist.