On Wikipedia (so reliable, I know), they say that HID lamps have a wall loading at or above 3W per square centimeter. Is this the definition of HID lamps? What category do carbon arc lamps fall under, or other incandescent arc sources? I thought carbon arc was HID, but they don't have walls, so are they? How about medium pressure mercury lamps (MA/V)?

Are there also definitions for low intensity, medium intensity, and ultra high intensity lamps?

Theoretically, if you has a thick basketball-size quartz envelope with electrodes that were only a centimeter apart inside and mimicking the characteristics of something like an MV lamp, would the low watt density per square centimeter of quartz wall exclude it from being considered HID?

I also hear that these lamps may have a minimum temperature requirement, but I can't pinpoint what that would be if that was the case. Is this a thing as well?

Have you ever taken the trouble to read books instead of just Wikipedia?

Some books are even available online as PDF files:

books about lamps on lamptech, James Hookers website

I can highly recommend it.

@Olav
Yes, that is an excellent resource, I have read many of those through in the "literature" tab. I just reread the Electric Lamps: Discharge book, but I once again didn't see any solid definition of HID lighting over there.

That said, I was hoping to get input on the question itself. Are you able to help with that? Do you know of a source that might have the answer?

It's similar to fishing—you have to wait...

Either you get a detailed answer here from people who are really knowledgeable,
or you can look for the answer in other books, but not online as a PDF.

Other book titles are:

- Electric Discharge Lamps, John F. Waymouth
- Discharge Lamps, Chr. Meyer, H. Nienhuis
- Lamps and Lighting, H. Hewitt

These books are available secondhand.

I would class carbon arc as HID, in simple terms, they’re an electric discharge of high intensity between two rods, ie, HID 👍

Go ask a linesman, commercial electrician, home electrician, and various electronics people in specific fields, what counts as "high" and "low" voltage

@AngryHorse
That is what I would think, but one of the definitions I came across specifically said that the light output shouldn't be by the incandescence of the electrodes (which CA is). I don't know why they made this distinction (or if it is even accurate). I always considered it HID but of course I don't know for sure.

@Ash
Of course for things like that there are many arbitrary personal definitions of high and low voltage. I was hoping there was a more concrete definition applying to discharge intensities.

Any light bulb that have a bright arc is HID. Fluorescent and LPS lamps, don't have a bright arc, so they aren't HID lamps.

Incandescence of the electrodes is only a side effect, the main light (including lots of UV in all spectrum ranges) is indeed from the arc. if it would be the main mechanism of light emission... well there is already another lamp doing just that



Well....

"The term 'medium voltage' is commonly used for distribution systems with voltages above 1 kV and generally applied up to and including 52 kV(1) and 69 kV(2)" (Schneider Electric)
(i.e. High voltage is above Medium voltage)
(1) IEV 601-01-28
(2) ANSI C84.1 (and here the Low voltage limit is 2.4kV, not the more or less commonly accepted 1kV)
https://www.electricalconnects.com/frontend/images/design_items/medium-voltage-technical-guide.pdf

NEC :
High voltage >1000V Anything
Low voltage <1000V Anything

IEC 61140 :
High voltage >1000V AC, >1500V DC
Low voltage <1000V AC, <1500V DC

IEC 62368 :
Applies to low voltage equipment, limit set at 600V
...
...

"Danger High Voltage"
(sign commonly posted on equipment which does not have any voltage over 400V)
...
...

"High voltage"
(refers to programming of EPROMs at 12V)
https://onlinedocs.microchip.com/oxy/GUID-8D61C0B9-A97F-4F4D-99F8-1D7424264C2A-en-US-1/GUID-CA9262E1-93FF-4B4C-910A-BD5BBEE477A3.html