# 208V vs. 277V in Commercial and Office Buildings



## grosshennig (Apr 22, 2010)

I know that 208V is used in small commercial or office buildings where 120V is used for lighting and power outlets (office equipment).
277V I guess is for motors and maybe lighting as well. (large commercial buildings)

I would like to find out how the typical (electrical) entrance to the building looks like.
(for office buildings, small commercial buildings, typical buildings from Walmart or Target, and others)
Which buildings have 277V vs. buildings with 208V? What is the allocation? Any guesses?

Are there any web sites with this kind of info?
Maybe books or other literature?

I appreciate any help,

Joe


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## Bob Badger (Apr 19, 2009)

We use many 'low' voltage systems in the US.

120/240 

208Y/120

240 

480Y/277 

480 

Sometimes

600Y/347

The reasons range from what the unitility is willing to supply, how much power is needed, how far we have to run the power, what voltage the equipment is available in etc.


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## Southeast Power (Jan 18, 2009)

I would suggest the NEC handbook. You might be able to get an older copy for a very reasonable price. Not much has changed in the way of utilization voltages here for a very long time.


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## John (Jan 22, 2007)

Bob you forgot about 4160 VAC. :icon_wink:

Like Bob said:

The most common ones are:

120/240 single phase for residential

208Y/120 three phase for commercial 

480Y/277 three phase for Big Box stores and industrial


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## John (Jan 22, 2007)

jrannis said:


> Not much has changed in the way of utilization voltages here for a very long time.


 Delta sevices are slowly going away because of the dangers associated with them and the FNG's not understanding them.


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## Bob Badger (Apr 19, 2009)

John said:


> Delta sevices are slowly going away because of the dangers associated with them and the *FNG's not understanding them.*


:laughing:

I have very little hands on experiance with either grounded or ungrounded delta.

480Y/277 and 208Y/120 is almost all I work on.

In my area 480Y/277 services are used very often in buildings you might not expect. A good example would be a strip mall, a small space would end up with a 100 amp 480 volt feeder from the main service.


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## Bob Badger (Apr 19, 2009)

John said:


> Bob you forgot about 4160 VAC. :icon_wink:


Not forgotten, .... excluded.


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## John (Jan 22, 2007)

Bob Badger said:


> Not forgotten, .... excluded.


You need to flood them with information ....it's fun to watch their head spin.


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## John Valdes (May 17, 2007)

John said:


> Bob you forgot about 4160 VAC. :icon_wink:


Why bring medium voltage into the mix here. It does not apply in his circumstance. To be quite frank it rarely applies to most all the work we do.



John said:


> You need to flood them with information ....it's fun to watch their head spin.


I would rather see them safe than their head spinning. :whistling2:


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## Skipp (May 23, 2010)

John Valdes said:


> Why bring medium voltage into the mix here. It does not apply in his circumstance. To be quite frank it rarely applies to most all the work we do. :whistling2:


 That's what I was just thinking. If we include 4160, why not mention 7200/12,470 - 4800/8320 - 7620/13,200 systems too?

To answer the OP question about 277 volt application. It is only used in lighting as far as I know. I never seen a 277 volt single phase motor. Maybe I'm wrong, I just never seen a use for 277 besides lighting.


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## frenchelectrican (Mar 15, 2007)

Skipp said:


> That's what I was just thinking. If we include 4160, why not mention 7200/12,470 - 4800/8320 - 7620/13,200 systems too?
> 
> To answer the OP question about 277 volt application. It is only used in lighting as far as I know. I never seen a 277 volt single phase motor. Maybe I'm wrong, I just never seen a use for 277 besides lighting.


 
Skipp.,

I have see couple 277 volts motours but not very common but the last time I have see it was used on triphase 480 volt heater unit

to OP 

The 277 volts is most common used for lighting circuit in USA side on larger commercal and industrial building { yeah there are other voltage as well }

The smaller commercal building will use 120 volt lighting circuits

All it depending on the power compaine supply with the load in there.


Merci.
Marc


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## John (Jan 22, 2007)

John Valdes said:


> Why bring medium voltage into the mix here. It does not apply in his circumstance. To be quite frank it rarely applies to most all the work we do.
> 
> 
> 
> I would rather see them safe than their head spinning. :whistling2:


John ...lighten up a little.
And you cannot tell us with a straight face that you have never sent a new guy out looking for a wire stretcher or a conduit straighter.:jester:

Read the Entire thread the next time.......see post #4:thumbsup:


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## Bob Badger (Apr 19, 2009)

Skipp said:


> To answer the OP question about 277 volt application. It is only used in lighting as far as I know. I never seen a 277 volt single phase motor. Maybe I'm wrong, I just never seen a use for 277 besides lighting.


Things I wire that are 277.


Lights, far and away the most common. (As you said)

Electric Heaters of many types.

Heat trace.

I cannot recall wiring a 277 stand alone motor but do see them in fan forced heating units.


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## Magnettica (Jan 23, 2007)

*FNG's*, what is this, Vietnam? 

lol


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## RePhase277 (Feb 5, 2008)

Bob Badger said:


> Things I wire that are 277.
> 
> 
> Lights, far and away the most common. (As you said)
> ...


I have also installed 277 V receptacles for thru-wall A/C units in some offices. Years back, Home Depot and I think Sears even used to sell 277 V window and thru-walls.


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## brian john (Mar 11, 2007)

Bob Badger said:


> I cannot recall wiring a 277 stand alone motor but do see them in fan forced heating units.



Years ago did a parking garage and we had 277 VAC fans in the garage corners for moving carbon monoxide (I assume) these fans only ran at peak garage use times. I assumed they were 277 VAC due to the lengths of the runs.


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## Bob Badger (Apr 19, 2009)

InPhase277 said:


> I have also installed 277 V receptacles for thru-wall A/C units in some offices. Years back, Home Depot and I think Sears even used to sell 277 V window and thru-walls.


Doh!, that reminds me.

I can't believe I did not remember I just bought some 277 volt 15 amp twist-locks for a job.

We installed 'De-stratification' fans in a couple of supermarkets and they were ordered 277 volt so we could tap the lighting circuits for them.

http://www.airius.us/products.php


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## one2question (Sep 2, 2010)

What I deal with is 120/208 or 277/480 in the same buildings. Reason lights, motors and recepticals. We use 208 because the utility normaly does not bring 3phase 240 in unless it is specified and typical we boost the circuit if a piece of equipment can not be bought in 208. Most commerical equipment is commonly in 120/208 or 277/480.


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## Skipp (May 23, 2010)

one2question said:


> What I deal with is 120/208 or 277/480 in the same buildings. Reason lights, motors and recepticals. We use 208 because the utility normaly does not bring 3phase 240 in unless it is specified and typical we boost the circuit if a piece of equipment can not be bought in 208. Most commerical equipment is commonly in 120/208 or 277/480.


 Usally when a building has 277/480 service, there is always a step down transformer involved. Otherwise you would not be able to use any 120 volt equipment. So if it's 277/480, there will also be 120/208 in the same building. Three phase motors usally have high and low voltage configuations these days.


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## Jeff000 (Jun 18, 2008)

John said:


> Bob you forgot about 4160 VAC. :icon_wink:
> 
> Like Bob said:
> 
> ...


If you are in Canada then 347/600 is more common for large commercial and industrial. Well Alberta at least.


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## brian john (Mar 11, 2007)

Bob Badger said:


> We installed 'De-stratification' fans
> http://www.airius.us/products.php


 
DE-*WHAT *fans? They assist in maintiaining consistent temps?


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## one2question (Sep 2, 2010)

Skipp said:


> Usally when a building has 277/480 service, there is always a step down transformer involved. Otherwise you would not be able to use any 120 volt equipment. So if it's 277/480, there will also be 120/208 in the same building. Three phase motors usally have high and low voltage configuations these days.


Some times, I have work 277/480 120/240 three phase and the occasional high leg. The high leg on either b or c phase depending on year built.


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## MDShunk (Jan 7, 2007)

For an office building, unless it's very large, it's almost certainly going to be 208. About the only time an office building is served at 480 is when the AC load is sufficiently large to demand it. In that case, really only the rooftop units (or chiller) and common area lighting are served at 480 and 277, and the customer owned transformer serves everything else at 120/208. Remember, most customers don't want to own a transformer if they can help it. Office buildings have nearly no PM, as part of their master plan. If they can serve everything at 120/208, that's what they're going to do. Very tall office buildings often have no choice but to go with 480, and often have a transformer every few floors (sometimes, on every floor), in the electrical room. 

For larger commercial, like large retail and factories, that's where you start to see 480 (and larger) services as common fare.


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## Jlarson (Jun 28, 2009)

Bob Badger said:


> Doh!, that reminds me.
> 
> I can't believe I did not remember I just bought some 277 volt 15 amp twist-locks for a job.
> 
> ...


WTH. Are your usual run of the mill fans not good enough any more?


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> For an office building, unless it's very large, it's almost certainly going to be 208.


Must be an area thing, we see 480 in offices all the time.

Well the ones we building, not necessarily the older buildings. 

The biggest buildings we see 208Y/120 services are hotels.


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## MDShunk (Jan 7, 2007)

Bob Badger said:


> Must be an area thing, we see 480 in offices all the time.
> 
> Well the ones we building, not necessarily the older buildings.
> 
> The biggest buildings we see 208Y/120 services are hotels.


Maybe. In my area, an office building is never going to see an electrician unless something breaks or there's a TI to be done. 208 is much easier for a handyman to get his head around. I'd never see a 480 service to an office building in my area unless it got to maybe 8 stories or above, or maybe over 70,000 square feet.


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## Bob Badger (Apr 19, 2009)

Jlarson said:


> WTH. Are your usual run of the mill fans not good enough any more?


The customer chose them and asked to install them. 

What would you do? :jester:

Actually the work really well, they shoot a rapid stream of air straight down to the floor in a very tight column from about 20' up. 

The customer tells me that they saved almost $4K in fuel bills at the first store they installed these in. (About 12 of the units in a 50,000 - 70,000 sq ft store with an open ceiling up to a 20' - 23' deck.

Seems like an exaggeration to me but no doubt they help get the heat down to the floor which a huge help in this area.

As a service guy you quickly learn that if it is 68F at the floor on a cold day that up at the deck it will be a 85 to 100 F.


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## Bob Badger (Apr 19, 2009)

MDShunk said:


> Maybe. In my area, an office building is never going to see an electrician unless something breaks or there's a TI to be done. 208 is much easier for a handyman to get his head around. I'd never see a 480 service to an office building in my area unless it got to maybe 8 stories or above, or maybe over 70,000 square feet.



Makes sense.

Here it seems they drop transformers around like they are candy. So you end up with a bunch of 45 and 75 Kva transformers all over with very little load on them. :blink:


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## Jlarson (Jun 28, 2009)

Bob Badger said:


> The customer chose them and asked to install them.
> 
> What would you do? :jester:


Say the look like a POS and then ask for a check and what time they want us to show up the next day. 

:jester:


> As a service guy you quickly learn that if it is 68F at the floor on a cold day that up at the deck it will be a 85 to 100 F.


We don't have a need for this heating thing you speak of out here.


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## Jlarson (Jun 28, 2009)

Bob Badger said:


> Makes sense.
> 
> Here it seems they drop transformers around like they are candy. So you end up with a bunch of 45 and 75 Kva transformers all over with very little load on them. :blink:


Not here, you ever see a multi room portable building shake and buzz cause someone way overloaded a xformer? The summer heat dosn't help matters either.


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## Bob Badger (Apr 19, 2009)

Jlarson said:


> Say the look like a POS and then ask for a check and what time they want us to show up the next day.


Working with them would not change your opinion, they feel like plastic European junk.

But as I said they work well, and they are quiet.



> We don't have a need for this heating thing you speak of out here.


I figured, that is why I was 'splaining it. :jester:


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## Jlarson (Jun 28, 2009)

Bob Badger said:


> Working with them would not change your opinion, they feel like plastic European junk.


The one that hangs in the joists looks like something that came from Ikea. Did they come in a box labeled some assembly required?:laughing:


> But as I said they work well, and they are quiet.


How long till the barrings go out and the sound like a food processor hanging up there?


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## Bob Badger (Apr 19, 2009)

Jlarson said:


> How long till the barrings go out and the sound like a food processor hanging up there?


Don't know. :laughing:

What is a barring?


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## John (Jan 22, 2007)

Magnettica said:


> *FNG's*, what is this, Vietnam?
> 
> lol


No it's not, but it's still an applicable acronym.....slightly above a DIY.


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## Jlarson (Jun 28, 2009)

Bob Badger said:


> Don't know. :laughing:
> 
> What is a barring?


IDK, doesn't it have to do with maps? B4T you are needed, we have a question in your area of "expertise".


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## John (Jan 22, 2007)

Jlarson said:


> IDK, doesn't it have to do with maps? B4T you are needed, we have a question in your area of "expertise".


B4T is busy......barring is New Hampshireese for bearing.


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## grosshennig (Apr 22, 2010)

Thanks for all the great feedback.

Nobody mentioned elevators in hotels and office buildings. Isn't this also a typical 277V load?


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## McClary’s Electrical (Feb 21, 2009)

MDShunk said:


> Maybe. In my area, an office building is never going to see an electrician unless something breaks or there's a TI to be done. 208 is much easier for a handyman to get his head around. I'd never see a 480 service to an office building in my area unless it got to maybe 8 stories or above, or maybe over 70,000 square feet.


 

This sounds like you're saying they design the services towards who's going to be working on them??? REally?


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## Vintage Sounds (Oct 23, 2009)

grosshennig said:


> Thanks for all the great feedback.
> 
> Nobody mentioned elevators in hotels and office buildings. Isn't this also a typical 277V load?


No, 277v is single-phase voltage to neutral derived from a 3-phase 480v Wye service(I think in Europe the term "star" is used more). It's almost always used for lighting only but like the other guys said, 277 space heaters and fans are sometimes used. The elevator motors will be 480v 3ø in a building like that.

Here in Canada the system is essentially the same but instead of 277/480v we use 347/600v. The 480v system allows for motors to be built with six or nine leads. Depending on how the leads are connected the same motor can be used on 480v or 240v 3-phase. On the other hand the 600v system can deliver the same total power with smaller wires but there is no dual voltage as nobody uses 300v.


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## frenchelectrican (Mar 15, 2007)

grosshennig said:


> Thanks for all the great feedback.
> 
> Nobody mentioned elevators in hotels and office buildings. Isn't this also a typical 277V load?


 
No the elevators are normally wired with three phase motours but few case some smaller one will use single phase motour and older one alot of the time you will run into old DC or 25 HZ motour { the 25 HZ motour is about history anyway } and they will use the M-G { motour generator }

Merci,
Marc


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