Is It Safe to Use a 250V Socket in a 277V Lighting Application?

[MacLaddy]

I have some recessed can lighting fixtures in a commercial application that was using compact 277v fluorescent bulbs (2x26w). I have purchased a can light fixture that will hold one spiral 277v fluorescent (27w), which allows us to get away from having to purchase two lights + ballast. However, the actual socket in this new fixture says it is rated for 600w and only 250 volts.

I would like any input you can offer on if this application is safe or not. I am guessing that it would be fine, as the amp draw from this one light is only 0.170A, but I wanted to see if there is anything I am not taking into consideration.

Any information or advice is appreciated.

Mac

 

[jim hardy]

Arrgh !

One of those things your common sense says it's fine

but you got to meet the letter of the specifications...

liability and all that.

Find the fixture's datasheet at manufacturer's website

and check your installation against the NEC .
There are separation requirements between 120/240 and 277/480 volt systems and from your description your fixture is 240 going into a 277 system. I don't know if there's any differences in mechanical construction or wire colors.
You don't want to do somethiing that's going to lead the next guy astray.

From a handyman's reference:
http://www.electrical-contractor.net/Education/Mike_Holt_Code_Q&A2.htm

Q10. I've been looking in the National Electric Code for hours. Does the NEC have any specific reference to wire color-coding for the phase conductors for a 3-phase wye system where the voltage between phases is 480 volts and the voltage to ground from each ungrounded conductor is 277 volts?


A. Yes and No. The NEC requires grounded (neutral) conductors to be white or gray [200-6], grounding conductors to be green or bare [250-119], and the high-leg conductor from a 120/240 volt, 3-phase delta system must be durably and permanently marked by an outer finish that is orange in color [384-3(e)].


Author’s Comment: The reason the high-leg conductor must be identified is because the voltage from this conductor to ground is 208 volts (120 volts x 1.732). Even with the identification of the high-leg, it is not uncommon for the installer to inadvertently connect 120 volt loads to this 208 volt to ground terminal within the panelboard, with unfortunate results (I did it once).


Where more than one nominal voltage system exists in a building such as 480/277 and 208/120, each ungrounded conductor of a multiwire branch circuit, where accessible, shall be identified by phase and system by separate color coding, marking tape, tagging, or other approved means [210-4(d)].


Author’s Comment: The NEC does not specify a color code to use, but the generally accepted practice is brown, orange, yellow and gray (BOY) for the 480 volt circuit and black, red, blue and white for the 120/208 volt system.

old jim

 

[wirenut]

The SOCKET is rated for 250 v and 600 W MAX.
The lamp operates at LESS than that.
Just because the input to the ballast is more (277v), doesn't mean the output of the ballast is that high. Most if not all fluor. lamps operate at much less voltage. You can verify this by looking at the ballast specs from the manufacturer.

 

[NascentOxygen]

Could MacLaddy confirm that the spiral compact tube has an integral internal ballast?

 

[MacLaddy]

Thanks for the replies everyone. I thought my question had disappeared into the bowels of PF, never to be seen again.

but you got to meet the letter of the specifications...

liability and all that.

Yeah, the icky word "Liability." That's exactly what worries me. I did install one fixture, and it seems to work just fine. However, my upper management decided they didn't like the look of the spiral fluorescent, so we will be staying with the original compact fluorescent.

The SOCKET is rated for 250 v and 600 W MAX.
The lamp operates at LESS than that.
Just because the input to the ballast is more (277v), doesn't mean the output of the ballast is that high. Most if not all fluor. lamps operate at much less voltage. You can verify this by looking at the ballast specs from the manufacturer.

Yeah, as I said in the OP the lamp itself operates at just over 1/10 amp, and only 27 watts. There was no real concern here, but I was worried about a liability issue just in case of some unforeseen failure.

Could MacLaddy confirm that the spiral compact tube has an integral internal ballast?

Yup, integral and internal.

 

[NascentOxygen]

The SOCKET is rated for 250 v and 600 W MAX.
The lamp operates at LESS than that.
Just because the input to the ballast is more (277v), doesn't mean the output of the ballast is that high. Most if not all fluor. lamps operate at much less voltage. You can verify this by looking at the ballast specs from the manufacturer.

Welcome to PF, wirenut.

I surmise that you are picturing an external ballast reducing the potential that appears across the lamp terminals. In light of the OP's indication he is using lamps with an internal ballast, then there can be no external ballast and therefore no difference between line voltage and what appears across the lamp socket. Besides, even were there an external ballast, picture the voltages when the lamp dies…

Good try, though. [/color]

 

[wirenut]

I did some checking on these, even though they are UL listed, I would stay away only because you are putting 277 volts on a e26 (standard incand. medium base). Unless the fixture is clearly marked as 277 volts there is a chance for injury or fire if a 120 volt lamp is installed. My next question would be- Is the new fixture rated for 277 volts? If you have a manufacturer name and model # it would help . I know the point is moot, but for info sake (so I can let guys @ work know to look out for them). I see BAD things happening. I also am not sure if they comply with the NEC. I'll have to look into that too.

 

[NascentOxygen]

I did some checking on these, even though they are UL listed, I would stay away only because you are putting 277 volts on a e26 (standard incand. medium base). Unless the fixture is clearly marked as 277 volts there is a chance for injury or fire if a 120 volt lamp is installed.

Are you saying that (wherever you are located) the sockets for
277V and 250V lamps are constructed so they will physically
accept 120V lamps?
Underscores the meaning of the word "incandescent", doesn't it?

 

[darkwood]

The dieletric strength of the lampholder is marked as you say for 250v, this is not to say it can't be used for your application, it is probably for a market where that is the common single phase voltage and thus printed to match the market its designed for, I am from England and our own Reg's now state that manufacturers recommendations must be adhered to, having said this if you can discuss with the lampholder manufacturers and get and email of confirmation that it will be ok to use at 277v then i feel you will have provided enough covering details to protect you from liability.
It just comes down to whether its easy enough to fit a lampholder yourself with the correct rating as I am sure if they sell the lamps at 277volts then surely lampholders should be within your reach too.
Our own voltage on paper changed 5yrs ago from 240v to 230v and over the years I've seen the exact same lampholders change their stickers to suit but our voltage has remained the same, you may find the lampholders are just sourced from another country and are ok to use but i reitirate that id get confirmation fron the manufacturers first.

 

[wirenut]

here is a TCP part # for a 277v compact fluor. spring lamp with a MEDIUM base-Product
Name: SpringLamp 42W 4100K 277V CFL

Product #: 28942-277-41K

Manufacturer: Technical Consumer Products, Inc., TCP

here is the product specs from the TCP website
Product Info

The TCP 289-series Compact Fluorescent SpringLamps feature lead-free glass for better lumen maintenance over life of bulb. End of life protection guards against violent lamp failures. New amalgam technology provides cooler operating temperatures for consistent performance in any position.
Specifications

Average Rated Life (hr): 10000

Base: Medium <------------------------- this is my concern

Color Rendering Index (CRI): 84

Color Temperature (K): 4100

Diameter (in): 2.8

Energy Star Qualified: Yes

Industry Standards: UL and CUL Listed, FCC Part 18, Subpart C

Initial Lumens at 25C: 2800

Maximum Overall Length - MOL (in): 7.0

Starting Temperature F (C): -20

Voltage: 277 <---------------- this too

Watts: 42
Here's a link to the info- http://www.tcpi.com/specsheets/AssociatedItems.aspx?DocumentID=2219&DescriptiveName=289%20Series%2018w-68w

I'm not sure if you understand my concern, but if someone unknowingly installs a 120 volt unit into a fixture wired for the 277v units WITHOUT any kind of warning label etc... best case the lamp burns out instantly... worst case catastrophic failure possibly fire, injury, death etc..

BTW I'm in new york