Why 277 volt lighting

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mbrooke

Batteries Included
Location
United States
Occupation
Technician
Why is lighting 277 volts and not 480 volts? Why do manufacturers make us pull a neutral? Seems we only have that option with HID. Irony is Mercury vapor high bays were often 480 volts.
 

mikeames

Senior Member
Location
Gaithersburg MD
Occupation
Teacher - Master Electrician - 2017 NEC
Less pratical???? Thinking of 2 spaces in a panel vs 1. For smaller areas the amount of lights that could be put on 1 480v circuit is not necessary, and so an extra space wasted????

I am just making it up, guessing. Why not 240v lights in residential?
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Less pratical???? Thinking of 2 spaces in a panel vs 1. For smaller areas the amount of lights that could be put on 1 480v circuit is not necessary, and so an extra space wasted????

I am just making it up, guessing. Why not 240v lights in residential?

In residential you could use screw shells as an excuse.

But in commercial tomb stones are different and I don't see a HO touching a mogul high bay socket.
 

kwired

Electron manager
Location
NE Nebraska
differences in design requirements for a 277 volt switch vs a 480 volt switch? plus it is single pole vs multipole, and associated price differences?

There probably was at one time 277 volt mogul based incandescent lamps. I know I have seen 277 volt quartz double ended lamps.
 

kwired

Electron manager
Location
NE Nebraska
What about 347/600 volt systems? Though not so common in the US. Don't know if there is common 347 volt loads that are typically supplied in these systems. Guessing there at least is some 347 volt loads though.
I was always told "it's below 300 volts" (and because it's a single pole breaker).
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Why is lighting 277 volts and not 480 volts? Why do manufacturers make us pull a neutral? Seems we only have that option with HID. Irony is Mercury vapor high bays were often 480 volts.
Who says it isn’t?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Not until recently did they start making 480 volt drivers. A lot of manufactures would use multi volt ballasts using the auto transformer taps to power the driver at a lower voltage.
 

norcal

Senior Member
What about 347/600 volt systems? Though not so common in the US. Don't know if there is common 347 volt loads that are typically supplied in these systems. Guessing there at least is some 347 volt loads though.

347V lighting is used in Canada.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician

mbrooke

Batteries Included
Location
United States
Occupation
Technician
differences in design requirements for a 277 volt switch vs a 480 volt switch? plus it is single pole vs multipole, and associated price differences?

There probably was at one time 277 volt mogul based incandescent lamps. I know I have seen 277 volt quartz double ended lamps.


They still make 277 volt lamps in normal base. I use them where the 240 volt ones burn out to fast.




I can see 277 volt lamps being more durable, long life and more efficient at 277 volts but florescent and HID would not make a difference I'd think. Remember that a 1000 mercury vapor bulb could run on a 480 volt reactor ballast.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
3 wires vs 4 wires. Lose a noodle and you smoke 100 ballasts. Line to neutral loads are just dumb, dangerous, and pointless.
My son is on a new construction job where the temps left a bunch of nuetrals loose, smoked quite a few drivers. If they had been 120 volt, no magic smoke would have been let out because of the 120/277 volt auto selecting. Unfortunately, 277 volt circuit, mwbc.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
My son is on a new construction job where the temps left a bunch of nuetrals loose, smoked quite a few drivers. If they had been 120 volt, no magic smoke would have been let out because of the 120/277 volt auto selecting. Unfortunately, 277 volt circuit, mwbc.


Yup, one the reasons why using the system's center point for load is dangerous.
 

StarCat

Industrial Engineering Tech
Location
Moab, UT USA
Occupation
Imdustrial Engineering Technician - HVACR Electrical and Mechanical Systems
3 wires vs 4 wires. Lose a noodle and you smoke 100 ballasts. Line to neutral loads are just dumb, dangerous, and pointless.
The Fact that you are raising questions about convention is good. I suggest looking into anything by Eric Dollard you can find.
There is gold in there.
What I will tell you that that besides the constant degradation in Engineered Systems due to everything being rooted in a debt based monetary system being bad, the Attempt to Engineer around common sense and proper education FOR PROFIT is a colossal mistake and can only end badly.
There is a major lot of time being wasted which people seem to think is normal, and we are getting more and more things that either work very badly or not at all. Its a form of collective insanity that is playing out with all kinds of people who should know better turning a blind eye to the entire affair.....


Star
 
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