Handyman Wire

Who's Online
0 registered (), 22 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Welcome Newcomers
Unregistered users may only post in the handyman forum. If you register, you may post in any forum and use of CAPTCHA code is not required.
Advertisement
Topic Options
#665802 - 05/11/11 05:57 PM 208v. vs. 240v. vs. 220v.
figaro Offline
enthusiast

Registered: 06/18/03
Posts: 205
Loc: Des Moines, Iowa
I am looking at a steam generator for a shower. It talks about 208v. or 240v. Is the 208v a european voltage?
Also, I hear most people refer to 220v but here they talk about 240v. Aren't ovens, dryers, etc. 220v.? What's the difference?

Thanks

Top
#665803 - 05/11/11 06:04 PM Re: 208v. vs. 240v. vs. 220v. [Re: figaro]
code_ceis Offline
Carpal Tunnel

Registered: 04/29/09
Posts: 7239
Loc: Seneca Nation
220 and 240 are the same just different names both are from a single phase transformer. 208 is a single phase tap of a 3 phase normally.
_________________________
It is a good day today. I woke up.

RIP RS

Top
#665804 - 05/11/11 06:21 PM Re: 208v. vs. 240v. vs. 220v. [Re: code_ceis]
figaro Offline
enthusiast

Registered: 06/18/03
Posts: 205
Loc: Des Moines, Iowa
"208v is a single phase tap of a 3 phase normally"

In laymans terms??????????
Thanks

Top
#665805 - 05/11/11 06:34 PM Re: 208v. vs. 240v. vs. 220v. [Re: figaro]
Gizmologist09 Offline
Handyman

Registered: 02/08/09
Posts: 606
Loc: Palmdale, California USA
208v is found in industrial settings as well as 277v and 480 volt taps. Industrial installations usually have a 480 volt feed from the power company and the facility then has a step down transformer that delivers 120 volts for offices etc and 2777 for lighting. Residential power in the US will be 220-240 between the phase legs in your panel. The device you are looking at will likely have a tap for power listed for 208 and another for 240. Just leave the 208 alone and use the 240volt taps.

Top
#665806 - 05/11/11 06:52 PM Re: 208v. vs. 240v. vs. 220v. [Re: Gizmologist09]
figaro Offline
enthusiast

Registered: 06/18/03
Posts: 205
Loc: Des Moines, Iowa
THANKS!!!!!!!!!!!!!!!!!!

Top
#665807 - 05/11/11 09:52 PM Re: 208v. vs. 240v. vs. 220v. [Re: figaro]
MCA Offline
Carpal Tunnel

Registered: 03/09/06
Posts: 4943
Loc: Illinois
120/240 (some say 110/220, 115/230/125/250) are from a split phase service as most houses have.
120/208 is a 3 phase Y system as found in commercial buildings. Industrial buildings may have a 277/480 3 phase Y as mentioned. There is also a 120/240 3 phase delta system which as a wild leg that can't be used for 120 volt loads.
Some apartment buildings are fed by a 120/208 system and each unit may have a single phase panel but it will be 208 instead of 240 because it was derived from a 120/208 3 phase system. A single house in a commercial area may have a 120/208 service even though there is only a single phase panel at the residence.

Top
#665808 - 05/11/11 11:07 PM Re: 208v. vs. 240v. vs. 220v. [Re: MCA]
Gizmologist09 Offline
Handyman

Registered: 02/08/09
Posts: 606
Loc: Palmdale, California USA
I didn't want to confuse the issue. I have never run into a residential 208 as that would pose a LOT of problems.


Edited by Gizmologist09 (05/11/11 11:09 PM)

Top
#665809 - 05/12/11 11:17 AM Re: 208v. vs. 240v. vs. 220v. [Re: Gizmologist09]
MCA Offline
Carpal Tunnel

Registered: 03/09/06
Posts: 4943
Loc: Illinois
Quote:

I have never run into a residential 208 as that would pose a LOT of problems.




Its somewhat common in larger apartment buildings (although the panel in the individual unit will probably be a single phase panel). Electric stoves and dryers will take longer to heat. The problem may be with a motor. An air cond. unit that is designed for 240 may have a problem with 208. If 10% variance from the voltage rating is considered acceptable then if it was rated for 230 volts then 230-(.10x230)=207. But after voltage drop the voltage may end up being under 208. Usually the acceptable variance is used to absorb voltage drop. A lot of commercial equipment is can be connected to 208 or 240. While most commercial buildings are 3 phase most newer ones are Y systems producing 208 but some older ones are delta systems producing 240.

277 volt lighting is interesting. 277 is the phase to neutral from a 480 Y service. When someone who know residential wiring doesn't know there are differences in non-residential systems and wonders why there is over 240 volts on a circuit and is surprised to hear that its supposed to be 277.
For those wondering why a nominal voltage numbers include 208 and 277 it has to do with the angles of the transformer windings and can be explained with triginometry.

Top



Moderator:  CabinConnection, Ernie, SpeedyPetey 


Experts | Email Us | Disclaimer | HandymanWire home
Articles | We welcome your feedback. | Privacy
http://www.handymanwire.com
Handyman Wire
your resource for advice on home improvement and repairs.
Copyright 2014, Handyman USA LLC.
All rights reserved.