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Changing a school worth of defective led light ballasts. So if I turn the switch off for the classroom is it completely safe to work on? Say I'm working a classroom on circuit 2, multiple classes are on circuit 2, and circuits 4 / 6 carrying loads as well. Even though the hot is off for that class, is there danger with the neutral from all the other energized stuff on the circuits?
 

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Coffee drinking member
I pretwist and then use wire nuts. Solder pots rule.
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Yes there can be
 

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Changing a school worth of defective led light ballasts. So if I turn the switch off for the classroom is it completely safe to work on? Say I'm working a classroom on circuit 2, multiple classes are on circuit 2, and circuits 4 / 6 carrying loads as well. Even though the hot is off for that class, is there danger with the neutral from all the other energized stuff on the circuits?

there should be a ballast disconnect installed
 

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corn-fused
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put a wire nut on it while you work. that makes it safer. oh, and dont stick your tongue on it!
 

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Donuts > Fried Eggs
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If you're not opening current-carrying neutrals and your LOTO'd switch is the only source of power, you're fine.

Beware of electronic switching. I once got my ass lit up by depending on that to completely isolate me; there is often let-through current.
 

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:-)
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I do them hot all the time. Be careful.

I just clip the hot and install a luminaire disconnect first. I use the existing wire from the bad ballast to do this and just check the existing wire nuts for tightness. I don't undo the connection.
 

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It's really not great practice to just do work by turning off the switch. I think our local had an apprentice die that way. If someone comes into the area and turns on the switch while you're working on the circuit, look out! As others said, most fixtures nowadays come with disconnects, but otherwise you could add one to make them code compliant. I don't believe neutrals are to be shared anymore either, however....

The best practice is probably to shut the whole circuit down and lock it out.
 

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I liked the old fixtures that used single pin lamps, and interrupting lamp holders. removing the lamps disconnected the power to the ballast. You did have to be careful as not all fixtures disconnected both the hot and the neutral, and the ones that only interrupted one side sometimes opened the neutral and not the hot. Was really nice to safely change ballasts without shutting down a bunch of lights.
 

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Note: EC&M ran an article several years ago about the most common place for shock injuries in out trade.......it was changing ballast..yep I will try to dig it up in their web site.....shock and then of coarse the fall from the ladder as the final icing on the hurt cake.:eek:
 

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Here is one:

If a lighting ballast fails, do you change it out hot? That's a fairly common practice, but you can get electrocuted by 277V just as surely as from a higher voltage. If you're on a ladder, the fall might kill you even if you survive the shock. When you lockout and tagout the breaker supplying that ballast, you inconvenience people who work in that area. Nevertheless, unwiring the ballast while hot puts you at risk.
If you really must change ballasts while others are working in the area (instead of between shifts), you can shrink the time window if you first wire the ballasts with listed quick disconnects. In fact, you can find quick disconnects made specifically for luminaires. These special connectors prevent reverse wiring and are finger-safe. Consequently, you can unplug the ballast just as safely as if you were unplugging a floor fan. You could convert to the quick disconnect configuration case by case as ballasts need replacement. However, consider scheduling a mass conversion during a normal plant (or office) shutdown, in a manner similar to mass re-lamping.
Caution: This quick disconnects don't eliminate ladder safety requirements. Rope off the area around the ladder. You don't want to drop a heavy tool onto someone's unprotected head. Nor do you don't want someone knocking your ladder over while you're on it.
 

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The prob is, nobody wants to be in the dark long enough for us to do our work



~CS~
 
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