Awesome, thank you.Yes, it'll do exactly that. As long as you aren't looking for 208 you'll be fine. Just watch your loads as usual.
Well YOU DO why do venues do this? I swapped out and rewired some dimmerpacks fitted with a recessed twistlock plug receptacle from 3- phase to single phase. FYI Unless you're in Philidelphia "actual 2- phases" is extremely rare." "Single phase inplies 2-legs of a Std. "Pole pig" but 2-phases is 2 of any 3 of the actual available allotment to your venue from a real 3/phase, 120/208" v-volt utility distribution system, such as in NYC All power is 3-phase. You just only get 2 "phases" @ your address, next door look for that 3rd phase.
Section 520 sidebar: I've got a new house with a main auditorium of 350 retractable seats, and it has zero utility receptacles around the walls. Is this the "over 1000 sq ft" exemption, or something else, would you think?The assumption of 520.53(B) is that when a road electrician with a 3-phase dimmer rack is presented with a split-phase
It's not 180°. Phase is a time-based phenomena; tell me how time was changed.
That leaves polarity. Tell me how a single, center-tapped transformer winding can change polarity.
The answers are neither time nor polarity, but contained within the Laws of Ohm. Maybe Kirchoff, too.
The YT video I link shows a DC source, with center tap, and all the batteries are in the same polarity, yet the same things happen with AC or DC.
Technically correct -- the best kind of correct -- but in fact, the 180 degree differential in phase between the two legs of a 120/240 service could be an artifact of either phase or polarity: it's impossible to distinguish or measure that on the wires.
As for centertaps, its because *the neutral is derived from the center tap*.
The distribution transformer is taking one leg of the 3ph distribution, at 1200VAC to ground or so, usually, and transforming it down to 240 (5:1), and then peeling a neutral off the centertap of that secondary. When one leg is at full, the other leg is at zero.
It's correct to say that's not a "phase" artifact, but in most cases, it's not terribly important.
I do not know of any "over 1000 sq ft" exemption in the NEC to which you refer.Section 520 sidebar: I've got a new house with a main auditorium of 350 retractable seats, and it has zero utility receptacles around the walls. Is this the "over 1000 sq ft" exemption, or something else, would you think?
In the 2023 NEC, there is no section 210.71.Section 210.71, apparently a fairly recent addition has a clause about meeting rooms larger than 1000 square feet. The section is supposed to apply to rooms where electronic devices will be brought and used but explicitly excludes auditoria, coffee shops, and schoolrooms. At least, that’s what the internet says.
Other than "because a neutral is derived from a center tap", there's nothing here, Jay. That's why I posted the video. The DC example behaves exactly like an AC circuit, but there is neither phase nor polarity at work in the example. And that, by itself, dispels most of the common assumptions about what is actually happening.Technically correct -- the best kind of correct -- but in fact, the 180 degree differential in phase between the two legs of a 120/240 service could be an artifact of either phase or polarity: it's impossible to distinguish or measure that on the wires.
As for centertaps, its because *the neutral is derived from the center tap*.
The distribution transformer is taking one leg of the 3ph distribution, at 1200VAC to ground or so, usually, and transforming it down to 240 (5:1), and then peeling a neutral off the centertap of that secondary. When one leg is at full, the other leg is at zero.
It's correct to say that's not a "phase" artifact, but in most cases, it's not terribly important.
Maybe it was in the 2020 edition? What would I know? I’m Canadian.
Section 520 sidebar: I've got a new house with a main auditorium of 350 retractable seats, and it has zero utility receptacles around the walls. Is this the "over 1000 sq ft" exemption, or something else, would you think?
Technically correct -- the best kind of correct -- but in fact, the 180 degree differential in phase between the two legs of a 120/240 service could be an artifact of either phase or polarity: it's impossible to distinguish or measure that on the wires.
As for centertaps, its because *the neutral is derived from the center tap*.
The distribution transformer is taking one leg of the 3ph distribution, at 1200VAC to ground or so, usually, and transforming it down to 240 (5:1), and then peeling a neutral off the centertap of that secondary. When one leg is at full, the other leg is at zero.
It's correct to say that's not a "phase" artifact, but in most cases, it's not terribly important.
sk8ersdad just posted the exemptioon I believe is being referred to. The wording of NEC used to be "Put in whatever is needed after the minimum requirements of a building are determined." But nothing like residential code where receptacles must be within 6' of any wall space or permanent fixed glass whereas any lamp with a 6' cord (which is pretty standard) can be utilized. Further improvements came in the late 30's with the REA requiring a minimum standard 60 amp fuse box for a stove, TWO 20a kitchen/ cooking circuits, (used to be one prior to 1967) and countertop outlet spacing hence 3' cords on most modern kitchen appliances. Butheck in some commercial establishments even receptacles are not required except in shop windows.
210.71, covering meeting rooms, went in to the 2017 NEC, but was moved in the 2020 edition to 210.65.Maybe it was in the 2020 edition? What would I know? I’m Canadian.![]()
What You Need to Know About the 2020 NEC Meeting Room Requirements - Connectrac
The National Fire Protection Association (NFPA) and the National Electrical Code (NEC) sets the foundation for electrical safety in commercial and industrial buildings. Years can go by, and codes remain the same, […]connectrac.com
NEC 2017 - 210.71 Meeting Room 12' Width Clarification
I have a room 11'-9" x 23'-9", (279 sq ft). Based on 210.71(B)(2) NEC 2017, "A meeting room that is at least 12' wide and that has floor area of at least 215 sq. ft. shall have at least one receptacle outlet located in the floor at a distance not less than 6' from any fixed wall for each 215...forums.mikeholt.com
Yes, I know it doesn’t apply and said so in my original post. That was sort of the point of the post.210.71, covering meeting rooms, went in to the 2017 NEC, but was moved in the 2020 edition to 210.65.
However, 210.65 does not apply to Jay's example:
"Section 520 sidebar: I've got a new house with a main auditorium of 350 retractable seats, and it has zero utility receptacles around the walls. Is this the "over 1000 sq ft" exemption, or something else, would you think?"
because of this informational note:
Informational Note No. 2: Examples of rooms that are not meeting rooms include auditoriums, schoolrooms, and coffee shops.
ST
"Damn it man! Stop agreeing with me!"Yes, I know it doesn’t apply and said so in my original post. That was sort of the point of the post.
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