What is everyone doing with regards to labeling single phase equipment? I made the decision to consider my "exception" to calculated labels to be "equipment less than 240V" since it has been explained on this forum that there is a misprint in 70E versus IEEE 1584, and the new 70E requirement will be reworded to cover equipment less than 240V. The problem is that this forces me in to labeling quite a bit of single phase equipment. I realize that the 1584 standard is not written for single phase, but 70E never says single phase equipment is excused from calculated labels. We are using Etap and it will be relatively easy to generate labels for single phase equipment. From what I understand, these calculations will be very conservative. Expanding into labeling single phase equipment will expand my study quite a bit.

The client that I do most of my work for has a label stating that the voltage is less than 240 volts, and supplied with a transformer less than 112.5 kva. They also listed the limited approach distance and Cat0 PPE... They are generic label and placed adjacent to the panel.

What is the general concensus for single phase 480 volt loads? We consider these as three phase loads and label them as such.

Single phase 480 will need an AF study done on them.. They are over the 240 volt guideline...

How can they say that a 120/240 volt panel is less than 240 volts?

So if your service is 490 volts phase to phase with no load, is that not a 480 volt service? I can see if Federal makes a 119/238 volt transformer so that it falls under the 240 volt guideline.. lol...

We commonly assume "less than 240 V" to be 208/120 Y and less only.
In some parts of the world, 220 V or 230 V are common distribution voltages.
You can even relatively easily buy three phase tranformers with three phase 240 V output, or 230 V output, or 220 V output. In North America, those are usually considered 240 V nominal systems, not 208 V systems.

Single Phase Arc-Flash methodology?

Is there an industry accepted method of calculating ARc-Flash incident energy for single phase systems?

Not yet. Unfortunately it is down on the list.

I just finished a review of a proposed new 1584 draft this week.

Still no sign of single phase. I'll be meeting with the committee in a few weeks and I'll post another update about what's going on when I return.

Just out of interest: have tests been done on single phase systems? Is there a difference in arcing current for solidly grounded systems?