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#16411 - 11/11/02 04:05 PM 277 volt medium base fixture  
Steve Miller  Offline
Member
Joined: Aug 2001
Posts: 325
Loudoun Cty, VA
Ok people help me here:
I have a 277v medium base recessed fixture in one of our schools. It uses 100 watt A-19 lamps at 277. We are still on the 96 code. As I read 210-6c this is not legal. 1) Am I missing something? 2) was it ever legal? I suspect the school was built under the 87 code.


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#16412 - 11/11/02 04:24 PM Re: 277 volt medium base fixture  
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
Steve,
I'm no whiz on lightbulbs, so correct me if I'm mistaken about that lamp being a plain old 120 volt incandescent lamp. If that is so, I've never seen one made for 277 volts, but I have heard of them being used on mine equipment. Are you sure the correct type of lamp is installed?

Are you sure the fixture doesn't have a step down transformer? If so & it is a listed fixture, it is in compliance with 210-6(c)(2).

Anyway, digging out my '87 codebook, this would have been a violation in the '87 code as there was not even a mention about a transformer & listed fixture, had to be a mogul base & electric discharge type lamp type or other type of base (such as fluorescent type socket).

Tom

[This message has been edited by Tom (edited 11-11-2002).]


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#16413 - 11/11/02 06:33 PM Re: 277 volt medium base fixture  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
FWIW, GE lists 277V 100-watt medium-base A-21 incandescents on page 17 of http://www.gelighting.com/na/downloads/02_inc.pdf Apparently UL does not list replacement lamps {or motors for other than NEC chapter 5 hazardous locations}. Isn’t the standard medium-based socket is rated something like 660W/600V?

Imagine a school janitor on a ladder changing a [120V in place of a 277V] lamp in a broom closet overhead fixture. Bulb rupture seems like a strong possibility.


#16414 - 11/12/02 02:32 AM Re: 277 volt medium base fixture  
nesparky  Offline
Member
Joined: Jun 2001
Posts: 642
omaha,ne
I would check the circuit voltage. I recall see some fixtures listed as max 250 and max 277v that were used on a 120 circuit with a A19 bulb.


ed

#16415 - 11/12/02 08:50 PM Re: 277 volt medium base fixture  
Steve Miller  Offline
Member
Joined: Aug 2001
Posts: 325
Loudoun Cty, VA
This is a 277 volt circuit. This is a 277v bulb, I have one in my hand right now. The prob, other than the question of legality on the use there is that the socket is rated 250v. The installer used a standard recessed fixture and wired it 277, probably cause the rest of the building is 277v fluorescent.
BTW Phillips makes them, they're $6 each.
And yes, it blow the 120 bulbs as soon as the people installed them (that's how I got involved in the first place).
Thanks for the info ref the 87 code.


#16416 - 11/12/02 09:04 PM Re: 277 volt medium base fixture  
caselec  Offline
Member
Joined: Apr 2002
Posts: 558
San Jose, CA
Steve

Since these fixture were not designed for 277V operation I would try to convince them to either move these lights to a 120V circuit or add transformers at each fixture. Halo makes transformers that mount in a 1/2" K.O. just for this purpose The Part #is H277. http://www.cooperlighting.com/specfiles/pdf/Portfolio/V985181.pdf

Curt


Curt Swartz

#16417 - 11/12/02 11:06 PM Re: 277 volt medium base fixture  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
There are medium-based sockets intended to withstand 5kV impulses for HPS lamp-ignitor starting.

http://www.leviton.com/sections/prodinfo/lamphold/sheets/70048.htm Published rating 660W/600V. [The GE-lamp pdf lists 250- and 300-volt lamps.]




[This message has been edited by Bjarney (edited 11-12-2002).]


#16418 - 11/12/02 11:45 PM Re: 277 volt medium base fixture  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,259
Fullerton, CA USA
The step-down xfrmr won't go by 210-6(c)2 because it is not anintegral component of the fixture.
Why not retrofit it to CFL like the others?

& be sure it's not an HPS, metal halide, or old MV fixture?? Some of the lamps look just like 120V-A19.


#16419 - 11/13/02 12:00 AM Re: 277 volt medium base fixture  
caselec  Offline
Member
Joined: Apr 2002
Posts: 558
San Jose, CA
Electure

The step down transformer I indicated is designed and UL listed just for this purpose. It might be a violation to us a Halo transformer on another brand of fixture but most recessed light manufactures have these transformers available. It is no different than the 120V or 277V transformers used to drop the voltage to 12V on low voltage recessed lights.

All of the CFL conversion kits that I have seen have an adapter that screws in to the existing medium based socket. I have never seen one that is designed for a 277V medium based socket.

Curt


Curt Swartz


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