ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 265 guests, and 15 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#16411 11/11/02 04:05 PM
Joined: Aug 2001
Posts: 335
S
Member
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.

Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
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).]


Few things are harder to put up with than the annoyance of a good example.
Joined: Apr 2002
Posts: 2,527
B
Moderator
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.

Joined: Jun 2001
Posts: 642
N
Member
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
Joined: Aug 2001
Posts: 335
S
Member
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.

Joined: Apr 2002
Posts: 558
C
Member
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
Joined: Apr 2002
Posts: 2,527
B
Moderator
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).]

Joined: Dec 2000
Posts: 4,294
Member
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.

Joined: Apr 2002
Posts: 558
C
Member
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

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5