The 2002 Edition as well as the next Edition of IEEE 1584 is applicable for voltages from 208V to 15 kV. This week’s question is about how many have voltages above 15 kV.

Here it is:

Does your company (or clients) have voltages above 15 kV?
Yes
No
Many Sites/Clients - Some do / some don't

I have a mine customer with a 22.9 kV internal distribution system with about a dozen double ended switching stations, and about 50 mobile substations. I have a couple chip mills which own the incoming equipment running at 35.4 kV (very rural). Those are just the ones I remember right off hand. I'm not trained in high voltage so I stay out of 69 kV.

Duke Energy is gradually moving from doing bare hands-live line not only at 230 and 115 kV but is finding it is advantageous and even using it at 69 kV. Granted at this point the arc length is so long that arc flash hazard really doesn't apply.

I voted yes but it is very minimal. We take delivery from our utility company at 34.5 kV. At our north sub it's an aerial feed (well, separate feeders) to two transformers, which we own, and step down to 12,470V and distribute from there.

At our south sub they are underground feeders to three 35kV pad mounted switches, which we own. From the switches we feed 34.5 pri/ 12,470 and 4,160V secondary transformers and distribute from there. The 4,160V are mostly chiller feeders but we do have one lone building still fed with 4,160V to the transformer primaries there. All our other buildings pad mounts are 12,470V primary. We own and maintain all the 12,470V and 4,160V distribution. Miles of cable across a college campus.

At our site we receive 115kV from the local utility and then distribute on our distribution system (mostly underground) at 115kV and 22kV to primary substations throughout our center. At primary substations, we transform down to 13.8kV, 6.9kV, and 2.4kV, although we have an ongoing project to eliminate 2.4kV as a distribution voltage and switch over to 22kV. We do not do any live work. Scheduled outages are employed for maintenance, modifications and new work. Since we model our system with ETAP, currently investigating their ArcFault module to do >15kV arc flash studies vs. using ArcPro as referenced in the CFR 1910.269, Appen E.

If you don't do live work, how do you test for absence of voltage as required by 70E and OSHA?

I have been a member of the forum for several years. I have viewed many of the posts. I do not have much time to respond to the posts.

I work for a consulting firm. We have performed Arc Flash Studies for about nine years. We perform studies for electric utilities, municipal utilities and industrial applications. We run the gamut of voltages. We analyze open air and “in a box�. The lack of equations, other than the Lee Method, makes is quite difficult to calculate reasonable energy values. I would like to see some additional methods for higher voltage calculations

the existing IEEE1584 year 2002 advocates the theoretically derived Lee method for cases where voltage is over 15kV. Also, Excel spreadsheet accompanying the existing IEEE 1584 year 2002 Guide provides with sample 68,800V arc flash calcs based on Lee method. Would the new upcoming IEEE 1584 foster the Lee method or would it promote a different method? If the Lee Method hasn't been denounced by IEEE committee than what is the upper voltage level it can be applied for per upcoming IEEE 1584 year 2018 edition?

We took out the reference to the Lee method so the door is open to other methods as well.
Specifically from the next edition:

"There are alternative calculation methods for system parameters which fall outside the range of the model."

We did not want to make it appear that the Lee method is the only method.

I didn't mean to imply that we didn't test for absence of voltage, apply protective grounds, etc. Simply explaining that our practice is to schedule outages on equipment and circuits that we plan to work on.

Thanks, Jim. What is the maximum voltage (68,800V or higher?), bolted current and gap for the Lee method per the existing IEEE 1584 Excel calculator? Also, what are the electrode configurations from upcoming IEEE 1584 for the Lee method to be applicable? All of them including VCB, VCBB, HCB, VOA, HOA? Just want to confirm the Lee Method equations for incident energy (7) and arc flash boundary (9) from the existing IEEE 1584 could still be used after new IEEE 1584 has been released and what are the Lee method limitations (voltage, gap, fault current, electrode configuration)?

Read carefully what Jim said.

At least from Draft 6 and I might have overlooked it, Lee has been completely removed and the upper voltage limit lowered to 15 kV. So it's no longer a method documented in IEEE 1584 so the rest of your questions don't really apply.

I did read it carefully. Per Jim, "the door is open to other methods as well". That confirms the Lee method has not been outlawed and can still be used within certain limits and for system parameters which fall outside the range of the empirical model. My question is very simple - what is the maximum voltage, bolted current and gap for the Lee method per the existing IEEE 1584 year 2002 Excel calculator? The calculator shows example of 68,800V system analysis using Lee method so I wondered is this the max voltage or the existing IEEE 1584 would allow using the Lee method at even higher voltage?

PaulEngr, don't bother to respond if you believe that my questions don't really apply. But if you could provide with the information I'm seeking that'd be greatly appreciated.

My mistake. I thought you were talking about "2nd edition" as Jim calls it. 1584-2002 actually documented three methods, Lee, the empirical model, and an equipment specific model, along with a ton of documentation of arc flash in general. It did not compare the models. In comparison it looks like from Draft 6 that the new edition is far more focussed on the new empirical model.

Lee has no limits in 1584-2002. It's a theoretical upper bound on incident energy but with two caveats. First it is an upper bound, even if it becomes a ridiculous upper bound which it does as voltage increases especially above 10 kv. Second it assumes incident energy is a point source and conditions are purely open air. So effectively I guess you could call it VOA only. It models the arc under the assumption that arc resistance maximizes power transfer and it's lossless. It eschews any physics considerations.

With no comparison, using 1584-2002 in some cases such as say 10 ka in a fuse protected starter at, 480 V, all three models apply. Outside of the empirical or equipment models only Lee can apply. But that doesn't mean that one model is more accurate than another, but again no comparison was made.

I think Paul did a good job of answering the question about the Lee method. IEEE 1584 is taking no position, i.e. above 15 kv the individual will need to decide which method may be appropriate. Basically we are taking ownership for what the IEEE 1584 working group and IEEE/NFPA Collaboration have done but don't want to suggest anything beyond that. Not much else to read into it.

As far as gaps, VCB etc. I put together a video that provides an overview of all this. https://brainfiller.com/videos/2018-edition-ieee-1584/ The new equations and methods are completely different than the 2002 edition. I hope everyone's comments help.

Thanks for your input, Jim. Lets forget for a moment about upcoming 2nd edition of IEEE 1584. For a someone who follows 1st and the only one IEEE 1584 year 2002 Guide and/or is using IEEE Arc Flash Excel calculator - what are the limits for Lee Method built in into the calculator. The Calc features 68,800V system analysis using the Lee Method. Is this the maximum voltage or the existing IEEE 1584 - 2002 would provide for even higher line voltage? I could not find the answer in my IEEE 1584 Guide hence asking.

From memory, I don't believe there was an upper limit. That skews the results to be extremely large for higher voltages (or "conservative" as some would say) That is also one of the reasons it is not referenced in the next edition - we don't want to field questions, endorse or anything like that. It is just out there. A good method back in it's day but of course, we know so much more now.