Disconnecting LED Drivers

[mjc1060]

I am installing a Lithonia LED fixture. I noticed the manufacturer did not include a disconnecting means for the driver. Does the NEC require a disconnecting means for an LED driver equivalent to what is required for a florescent ballast? This luminaire is a pendant fixture hung below a suspended ceiling fed by a cable that terminates in a 1900 box above the ceiling. The driver is 208V on the line side.

 

[JFletcher]

See 410.130(G)

 

[chris kennedy]

See 410.130(G)

Camping, no NEC but sure that applies to double ended fluorescents only.

 

[don_resqcapt19]

410.130(G) Disconnecting Means.
(1) General. In indoor locations other than dwellings and associated accessory stru ctures, fluorescent lumin aires that utilize double-ended lamps and contain ballast(s) that can be serviced in place shall have a disconnecting means either internal or external to each luminaire. ...

 

[mjc1060]

Great answers is a Data Center a commercial or industrial facility?

Great answers is a Data Center a commercial or industrial facility?

The LED luminaires are installed in the server room of a data center. There are 3 general lighting and one EM circuit for these lights. The general lighting circuit is a 277V 20A multi wire branch circuit with a common neutral conductor. The fixtures are installed 3 for each server aisle way with an EM circuit powering the center luminaire and the general lighting powering the outside. This way lighting circuits can be shut down and the room will not go dark. This is an information technology center so that exception 4 for industrial facilities does not apply unless I am wrong about the classification of the facility., Are data centers considered commercial or industial facilities? These fixtures are supplied by a 1900 box that is connected with a fixture whip to the branch circuit box. The 1900 box is fastened to the ceiling grid where the cable feeds the suspended luminaire from the ceiling. This eliminates any chance of opening a neutral conductor splice of the multi wire circuit feeding the light fixtures . But even though the code specifies disconnecting means for electric discharge only, not using individual disconnecting means for a driver simply because its LED, I feel that safety can be compromised.

 

[don_resqcapt19]

The LED luminaires are installed in the server room of a data center. There are 3 general lighting and one EM circuit for these lights. The general lighting circuit is a 277V 20A multi wire branch circuit with a common neutral conductor. The fixtures are installed 3 for each server aisle way with an EM circuit powering the center luminaire and the general lighting powering the outside. This way lighting circuits can be shut down and the room will not go dark. This is an information technology center so that exception 4 for industrial facilities does not apply unless I am wrong about the classification of the facility., Are data centers considered commercial or industial facilities? These fixtures are supplied by a 1900 box that is connected with a fixture whip to the branch circuit box. The 1900 box is fastened to the ceiling grid where the cable feeds the suspended luminaire from the ceiling. This eliminates any chance of opening a neutral conductor splice of the multi wire circuit feeding the light fixtures . But even though the code specifies disconnecting means for electric discharge only, not using individual disconnecting means for a driver simply because its LED, I feel that safety can be compromised.

In my opinion, a data center is a commercial occupancy... an industrial occupancy produces a physical product.
You can do what ever you want to, but disconnects are not required for those fixtures. The safety issue is with replacing ballasts in florescent fixtures, most LEDs are not designed with field replaceable parts, so there is no need for a disconnect.

 

[JFletcher]

Camping, no NEC but sure that applies to double ended fluorescents only.

Yes I know, but I figured having the OP read the code section and those around it might be better than a simple "no" to his question, especially since I dont have a 14 NEC in front of me.

 

[Electric-Light]

The only difference between an LED ballast and a fluorescent ballast is what's on the load end and the ballast can fail and a disconnect would be beneficial for the same purpose.

 

[Smart $]

The only difference between an LED ballast and a fluorescent ballast is what's on the load end...

:lol: That's like saying the only difference between black and white is color. :slaphead:

...and the ballast can fail and a disconnect would be beneficial for the same purpose.

Beneficial, but as already noted, not required.

 

[Fulthrotl]

Beneficial, but as already noted, not required.

i've not seen a LED fixture that doesn't come with
a disconnect plug yet....

i am seeing a failure rate in the DMF elements i put
in my house, however. they are the first generation
modulars, and i've had four now, out of fifty, fail.
they start fluttering. i was talking to my wholesale
house about this, and his observation was that the
first runs of the DMF elements were bulletproof, no
failures. not so much now.

oh, joy. they were about $75 a pop when i bought them.

life goes on.

 

[Electric-Light]

:lol: That's like saying the only difference between black and white is color. :slaphead:



Beneficial, but as already noted, not required.

Discharge lights require a ballast unless you're talking about vintage filament ballasted mercury vapor. Unfortunately modern solid state parts like electronic ballasts and pulse start starters are more likely to suddenly fail and disconnects gives a means to safely service something. Secondary of many LED ballasts are non-insulated and often rivals the voltage of ordinary T8 ballasts which puts working on the lamp side at similar risk level as fluorescent lamps. The code should be updated to include all luminaires containing power conversion devices including LED ballasts.

 

[Smart $]

... Secondary of many LED ballasts are non-insulated and often rivals the voltage of ordinary T8 ballasts which puts working on the lamp side at similar risk level as fluorescent lamps. ...

I can't say I've been keeping abreast of developments with LED lighting, so please correct me if I'm wrong. TTBOMK, common LED-lighting drivers generally have a low output voltage. Just what I have looked at have had like 56V tops. Certainly none in the kV range like fluorescent ballasts. Any uninsulated energized part on the secondary to me is an indication of a low voltage output and deemed "touch safe" per the UL standard it is listed under.

 

[Electric-Light]

I can't say I've been keeping abreast of developments with LED lighting, so please correct me if I'm wrong. TTBOMK, common LED-lighting drivers generally have a low output voltage. Just what I have looked at have had like 56V tops. Certainly none in the kV range like fluorescent ballasts. Any uninsulated energized part on the secondary to me is an indication of a low voltage output and deemed "touch safe" per the UL standard it is listed under.

LED solid state fluorescent lighting apparatuses and incandescent lamps are available in UL Class 1 and 2. An Edison base is a Class 1 circuit. An isolated low VA capacity 12v LV lighting circuit is Class 2 even though both circuits can utilize incandescent lamps. An LED element operates at 3-4v, so LEDs can be applied for class 1 as well.

The inherent nature of commercially practical discharge lamps are only available in class 1 because of the voltage required to sustain the operation of the smallest element, which starts at 50v and higher.

A typical 48" T8 lamp operates at 180v-220v at tens of KHz with common open circuit voltage around 600v.

Most modern LED lighting devices use multi die solid state fluorescent lamp packages. Each package contains multiple blue LED elements connected in series for nominal voltage around 12, 24 and 48v which all share the phosphor blend and the package. These packages are then arranged to form another sub-module. As an example, the load side of Cree LED light bulb is DC 230v driving multiple LED SSFL packages in series. Either leg can fault to ground hence the warning to never operate with a broken dome.
LED sign ballast such as the Philips Advance 150W can hit 400V.

Modern T8 fluorescent ballasts have 90-95% line to lamp current regulated power delivery efficiency with adequate electrical regulation to achieve single digit flicker percentage and a flicker index below 0.1.

Class 2 LED ballasts struggle to reach this level of line-to-LED delivery efficiency. If the LED lamp module and ballast are sold separately, the rating may not be based on line to light output lm/W. To reduce ballast loss, thus raise line-to-output lm/W, many LED products are using unisolated class 1 ballast that carry the same hazard as normal discharge lamp circuits. Flicker performance of some LED products are on par with red neon signs.