I see that the 2018 draft is available for purchase from IEEE. I am wondering how close the final will be compared to the draft and if it is worth buying the draft now. Anyone buy it yet?

As Vice-Chair of IEEE 1584, I keep getting reminded to not make public/official statements but this time I will because this is too important.

I have received quite a few similar comments/questions via email about a draft for sale and was quite surprised the first time I heard about it. Voting/recirculation ballot for DRAFT 4 just finished YESTERDAY! A few of us are meeting in a couple of weeks to prepare Draft 5 so why on earth an earlier draft is officially for sale is beyond me. Each subsequent draft has had quite a few revisions in order to resolve numerous comments, outstanding issues etc. Some are quite significant.

Too many people seem to want to jump the gun and begin touting this but it is way too early!!

I will leave it with the proverbial "Watch this space for further developments"

Thanks for bringing this up, it is really confusing people and I hope this helps clarify things a bit.

Thanks for the reply and update. One of my reasons in asking is that the most recent SKM release, V8.0.2.8, the Arc Flash module has been updated to include the IEEE 1584-2018 draft published in March 2018.

They, along with the other S/W companies were part of the development and review of the equations and standard. It seems a bit premature in my opinion (and the opinion of other's that I talked with today.) This has the possibility of really confusing things as we are seeing right here - not to mention legal implications if someone gets it wrong using a draft instead of the final version. We are still sorting out a few details. Draft 5 is right around the corner!

I provided a more detailed update regarding IEEE 1584 in our "Grey Matter" newsletter last week.

IEEE 1584 Update

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In reviewing D6 four things jump out at me:

1. Enclosure size will need to be measured. Adds a little time because previously nobody collected this data. No defaults listed.
2. Electrode orientation is task specific. So depending on the task we get different incident energy. Everyone was already bitching about no one size fits all.
3. The “125 kva exception” is now more like maybe 25 kva and does not include a voltage cutoff.
4. Looks like arcing current will go down especially with no more fixed 85% minimum. So incident energy will usually go up.
5. Two second rule is more clear and more of a rule.

Where did you obtain D6 from?

Leaked out of IEEE Xplore.

There are still standard enclosure sizes - more of them. I expect many will default to these (with a few new ones) as in the past.

This was a result of a few questioning the original IEEE 1584 work stating different electrode configurations result in different incident energy. True statement. But... be careful what you ask for. Some may simply keep the electrode configuration as it has been - Vertical Electrode in a Metal Box/Enclosure (VCB) unless they want to get creative and perform a lot of review of bus configurations. Horizontal Electrodes in a Metal Enclosure results in an incident energy upwards of 3 TIMES the existing VCB configuration

This was painful. It now states "sustainable arcs are possible but are less likely in three phase systems operating at 240 V nominal or less with an available short-circuit current below 2000 A."


The 85% was a simplistic approach for the case where the actual arcing current might be less than the calculated arcing current. It is for 208V up to 1 kV only. The new standard has a pretty elaborate method for calculating the arcing current variation correction factor. It applies for all voltages from 208 to 15 kV


This is pretty much as it was and is located in Section/Clause 6 Analysis Procedure.

I recorded an hour long video that was finished this past Friday where I attempt to explain some of the changes and the history of how we got here. The bottom line as I state in the video is when IEEE 1584 was published in 2002, it was the greatest breakthrough at the time for arc flash studies and calculations. However, a few international experts began attempting to call it into question - basically that it didn't cover many other things. Considering what it was in it's day, it was great!

However, these items as well as others were considered for the next edition and the IEEE/NFPA Arc Flash Research Collaboration was created for the next edition. There are just shy of 1900 new tests for more precision and a more (understatement) detailed model. Some of the equations now have 13 COEFFICIENTS! Before you ask, yes the software companies are on board and were an integral part of the work.

You can see the update video here:2018 IEEE 1584 Update Video

Draft 6 is the latest (and hopefully last) draft. It is available from IEEE as I understand for transparency purposes i.e. a few of us have the draft (and wrote it) so others can have access too. I'm really not sure when it will be approved and published - I am hopeful it will be before the end of the year. There are a few hurdles yet to clear but it is looking good. ...finally!

Can you say at this point whether or not the tweaked formulas and co-efficients typcial result in a higher or lower or largely unchanged calculated incident energy?

I realize every scenario is different blah blah but if there is a trend one way or another it would be interesting to know.

Thanks.

There was a preliminary comparison made a while ago. If the input/configuration is the same as 2002 i.e. using the Vertical electrode configuration, lumping them into categories i.e. 4, 8, 25, 40 cal/cm2 only a few went higher or lower. Most were in the same ball park.

The real issue is with the new electrode configurations. VCBB Vertical with a barrier can approximately double and HCB - horizontal can approximately triple the incident energy. At this point, i see it going one of 2 ways. People will either keep things the same or some will be "conservative" using HCB. A bit of a story behind the new configurations. The proverbial "watch this space for further developments" comes to mind.

At this point I think most sites that care about arc flash have gotten wise to the "conservative" approach and are smart enough to ask questions when they see results that are obviously stupid. It's going to be hard to cram a 300%+ increase down their throats without someone asking questions for justification.

For some equipment the electrode configuration is fixed. For example it explains EPRI's well documented evidence of extremely high incident energy with certain types of meter sockets which are basically the HCB configuration.

But with most current model MCC's and switchgear, it's more of a mixed bag. With switchgear HCB is just about the norm for racking configurations. MCC's kind of look the same if they are racked while energized but the actual failures I've seen have all been VCB where the arc travels down to the bottom and blows the bottom door off. But once we get away from racking the vast majority of tasks involve equipment in a VCB or VCBB configuration so hopefully this encourages task-based analysis rather than just trying to come up with generic numbers for everything.

Hello Jim,
I'm a distribution network engineer with AEP and have been briefly reviewing Std 1584 D6 and wanted to share some thoughts and questions. In reviewing the most significant changes thus far, I wanted to ask you how this edition applies to Network Protectors in an enclosed space (subsurface transformer vaults). Is there going to be more information in the final release to help define the class of equipment for 600V rated network protectors and also the electrode orientation? We utilize Eaton’s CM52 network protector (and others) in various sizes. The sizes of the protector range from a 2000amp approximately (43”HX27”WX21”D) up to a 4500 amp protector approximately (52”HX41”WX25”D). In a typical design the protector is transformer mounted with secondary bus bars bolted together horizontally into the enclosure then extends up through bolted fuses to the exterior bushings. In my opinion it is unclear how to properly classify the electrodes as they are both horizontal and vertical within the enclosure. I do realize there is the enclosure correction factor, but will there be literature to define this more in the standard? My next thought, is any of this arc flash information relevant for network protectors when performing work when the primary side is de-energized? Referring to the 2015 EPRI technical report on 480V network protectors, arcing did not sustain longer than 1.5 cycles inside the enclosure when high side is de-energized, reducing the incident energy to below 8 Cal/cm2. Do you have any thoughts on this? Thanks for taking the time to review this, any information would be greatly appreciated.
Thanks sir.

IEEE 1584 includes testing with various configurations of bus bar. You're not really giving enough information to quantify a result using the new or even the old IEEE 1584 equations. For a variety of reasons network protectors really don't fit with the IEEE 1584 model, especially because the bus gaps are way too wide. That's why EPRI did equipment-specific testing. This should always be preferred to more "generic" testing such as IEEE 1584, or to truly theoretical guesswork like the Lee equation.

Jim,

Any new updates? In a post here you mentioned possibly by the end of the year for approval.

It is still quietly winding it's way through the home stretch. I am still pretty sure it will be published sometime between now and the end of the year.

https://www.gdsassociates.com/wp-content/uploads/2018/11/2019-Hi-Line-Webinar-Schedule-Fillin-Reg-Form.pdf

I ran across this today: Elimination of the 2 second rule? Has this changed since D6 and the August 20 post above?

A few incorrect or confusing statements in this link above. Not sure where they received their information.
Below is a quote from the linked article (as it appears today) with my comments/clarifications in red.

"IEEE Standard 1584 was updated in late 2018. Significant changes were made that could change the PPE used by electric utilities. These changes include elimination of the 2 second rule, < Incorrect statement - the 2 second rule is still there > elimination of the exception for transformers below 125 kVA < Replaced by a current of 2 kA >, and elimination of the 85% rule. < A more detailed "Arcing Current Variation Adjustment Factor" calculation replaces this for more accuracy > Further, the calculation now includes more shape factors < There is no such term as shape factor in the new edition. There are new electrode configurations and enclosure size adjustment factors > for arcs that are considered to be enclosed in switchgear or similar enclosures. The new calculations are more accurate, but present challenges for electric utilities.< What type of challenges? > This webinar
addresses the changes and the new calculation methods."

Thanks. Guess they need to sell webinars before all the relevant facts are in.