When I opened a neutral splice in a fluorescent fixture once, that was still energized it felt like I was kicked in the head by a horse!

410.130(G) Disconnecting Means.

(1) General. In indoor locations other than dwellings and associated accessory structures, fluorescent luminaires 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. For existing installed luminaires without disconnecting means, at the time a ballast is replaced, a disconnecting means shall be installed. The line side terminals of the disconnecting means shall be guarded.

Exceptions are open for discussion. Also what is different about "dwellings and associated accessory structures"?

Maybe the lesson is that instructors should stick to seminars, and inspectors to inspecting - and that neither has any business using tools?

It's all warm and fuzzy to write a nice rule ... but we saw a preview of this when the NEC required panic hardware on certain doors. What sort of hardware, and installed by whom?

The devil is in those details, and we've discussed them here a few times.

"For existing installed luminaires without disconnecting means, at the time a ballast is replaced, a disconnecting means shall be installed." is new in the 2011 NEC

Again, what is different about "dwellings and associated accessory structures.

PS: I should have mentioned that my first electrician's license was back in 1962 as an E4 in Connecticut.

Reno;
Don't forget that wonderful rule that ALL motors had to be the much more expensive energy efficient type.
Even that monster 100 Hp motor on the fire pump that runs 15 minutes a year for testing...and hopefully never needs to run to control a fire!
That's money that could have been better spent buying a better quality switchboard, etc.

Joe:
Back to your question.

Perhaps it's a numbers issue, as there are (on average) fewer fluorescent fixtures within a resi than comm?

The intent of reducing/eliminating a possible hazard to untrained (or under trained) unqualified persons would be the same in any location IMHO.

I still come upon the occasional jobsite where the 'factory' 'sta-con' connectors are cut off & laying on the floor.

Another issue is how is this to be enforced with replacement ballasts? Here the replacement is considered an 'ordinary repair' and no permit/inspection is required.

Ahh ... an interesting detail, that fixtures used in homes need not have the disconnects.

Perhaps this is related to a)the ban on 277 lighting in homes and b)the documented deaths of electricians replacing 277 ballasts 'hot?'

As I've observed here before ... even lacking a NEMA standard on the disconnects, the entire issue would be decided if only ONE ballast maker - Advance - were to include the gizmos with their ballasts. Advance has a large enough market share that their choice would become the 'de facto' standard.

I think it has to do with the boss in an office insisting that you work it hot, while the boss at home is either the homeowner or their spouse.

This "other than dwellings and associated accessory structures" wording goes back first to the Proposals for the 2005 NEC®. Back then, this 410.130(G) was numbered to fall into 410.79 and was ultimately designated as 410.79(G).

From the May 2004 ROP, Proposals 18-92 (Log #1780) from Craig Wellman and 18-93 (Log #3421) from Danny Liggett proposed this requirement, each with slightly different wordings.

The original wording in those Proposals was "other than dwellings and related/associated outbuildings".

For your question, a portion of the Substantiation to P18-92 (Log #1780) goes to the heart of your question:
"In commercial, industrial, institutional and government facilities, it is often unsafe or impractical to turn off power to luminaires at the panelboard. Turning off the power may leave a room in the dark or may reduce illumination, which in some cases can/could create work related hazards for facility occupants. ..."

So, reading between the lines, the distinction seems to be that dwellings and associated accessory structures are exempted from this luminaire disconnect requirement because:
• dwellings are not as large as those other occupancies to have as great a distance between panelboard and the luminaire being serviced
• rooms in dwellings generally have windows (for fire egress) that allow natural illumination whereas those other occupancies more typically include rooms without windows

Brian_Rock:

Welcome to ECN forums from one of the 'Jersey Guys'!!

Thanks for the detailed information on this subject.

so the large facility being hazardous to operate in the dark validates 70E for a signed waiver to be written every ballast change motivated this code?

~S~

No, the Code change itself was motivated by servicer injuries. This is noted in that ROP and ROC elsewhere in the Substantiations and in the CMP's Statements.

I was specifically addressing Joe Tedesco's question regarding why the NEC® treats dwellings differently on then-410.79(G) / now-410.130(G). The Proposers were explaining why they were omitting dwellings in the portion I cited.

I don't under stand why they would want untraind persons changing ballast's in the first place.

you would think that would lead to more work place accidents not less...

Great post Brian and Welcome to the forum..

Yes, i understand the CMP have substantiations they base code changes on Brian

but i question those service injuries, and would wager many are the sign guys, or maintenance men

Certain electrical equipment are manufactured with these sorts in mind, like fusible disconnects that have an interlocking door mechanism cutting power to the fuses

Yet here we have a code requesting these same sorts, who will never own a copy of the NEC, install a safety device

So their substaintiation is rather cyclical logic

just imho....

further still, i bought a tin of these>



i'm less than impressed

~S~

Dwellings include multifamily like the one I live in and there are many ballasts installed in the underground parking garage, storage rooms, electrical closets, and stairwells. They should make it clear that these types of buildings should meet the main rule.