Post by thread:[EE] 280VAC in EXIT sign

I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. I discovered the sign was being fed 280VAC. This was stepped down to 120VAC for the lights in the sign. Is this a common practice ? POD Gus Calabrese

Gus S Calabrese wrote: > I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. > > I discovered the sign was being fed 280VAC. This was stepped down > to 120VAC for the lights in the sign. Is this a common practice ? > > POD Gus Calabrese > Yes. Its cheaper power. --Bob

At 03:47 PM 6/2/2006 -0600, you wrote: >I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. > >I discovered the sign was being fed 280VAC. This was stepped down >to 120VAC for the lights in the sign. Is this a common practice ? No, but 208VAC is. (sqrt(3) * 120VAC) >Best regards. Spehro Pefhany --"it's the network..." "The Journey is the reward" spam_OUTspeffTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Bob Axtell wrote: > Gus S Calabrese wrote: > >>I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. >> >>I discovered the sign was being fed 280VAC. This was stepped down >>to 120VAC for the lights in the sign. Is this a common practice ? >> >>POD Gus Calabrese >> > > Yes. Its cheaper power. > > --Bob Cheaper wire anyways, once out of the residential realm don't be surprised by anything, 600v wall heaters etc. D

At 03:47 PM 6/2/2006, Gus S Calabrese wrote: >I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. > >I discovered the sign was being fed 280VAC. This was stepped down >to 120VAC for the lights in the sign. Is this a common practice ? Yes, it is. I think that you will find that all the room lighting is running at 277 Vac. That's one leg of a 480 Vac distribution system. There are good (almost compelling) reasons to do this . . . but I won't get into that here. Suffice to say that it is regarded as common practice. dwayne -- Dwayne Reid <.....dwaynerKILLspam@spam@planet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 22 years of Engineering Innovation (1984 - 2006) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.

When I worked building maint. in a large mall all the bulbs were rated 240 V fed with 120V. They seemed to last for ever. On a lot of other lighting, such as fluorescent, it was 277V. Gus S Calabrese wrote: >I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. > >I discovered the sign was being fed 280VAC. This was stepped down >to 120VAC for the lights in the sign. Is this a common practice ? > >POD Gus Calabrese > >

> At 03:47 PM 6/2/2006 -0600, you wrote: >>I was asked to repair some EXIT signs ( in Colorado, USA ) in an office. >> >>I discovered the sign was being fed 280VAC. This was stepped down >>to 120VAC for the lights in the sign. Is this a common practice ? > > No, but 208VAC is. (sqrt(3) * 120VAC) What the above means is that 208VAC is the phase-to-phase voltage on a three phase system with 120VAC phase-to-neutral. This is commonly used for lighting in industrial/commercial settings. IIRC, another common industrial practice is a three phase system with nominal 480VAC from phase-to-phase and 277V from phase to neutral. This may be what you are seeing. Bob Ammerman RAm Systems