Drastic change: 410.73 (G)

[jim sutton]

410.73 (G)

What do you guys think of this article?

Disconnects will be required on flourescent fixtures!

Unless you dont pull multi-wire circuits and you have at least 2 switches in each room! (excep. 5)

This will drastically change commercial wiring!

[ September 09, 2005, 10:06 PM: Message edited by: jim sutton ]

 

[roger]

Re: Drastic change: 410.73 (G)

Jim, I think this will end up being more of a manufacturers concern than ours. I envision some type of modular disconnecting plug/switch integral to the fixture.

Roger

[ September 09, 2005, 10:21 PM: Message edited by: roger ]

 

[infinity]

Re: Drastic change: 410.73 (G)

Personally I don't like it, but I'll assume that fixture manufacturers will start making fixtures with an integral disconnect. Otherwise I see this as a very costly requirement.

 

[infinity]

Re: Drastic change: 410.73 (G)

Damn, Roger types faster!

 

[roger]

Re: Drastic change: 410.73 (G)

Originally posted by infinity:
Damn, Roger types faster!

But, we are on the same page.

Roger

 

[jim sutton]

Re: Drastic change: 410.73 (G)

Thanks guys,

Could it be that the mfgs will make a lot of money on this? Since it will be a huge labor saver vs the alternative that they created.

Those guys are geniuses!

 

[roger]

Re: Drastic change: 410.73 (G)

Originally posted by jim sutton:
Thanks guys,

Could it be that the mfgs will make a lot of money on this? Since it will be a huge labor saver vs the alternative that they created.

Roger

 

[cselectric]

Re: Drastic change: 410.73 (G)

I think the intent of 410.73(G) is good. And it may, by default, actually have a positive effect on safety. My hunch is the manufacturers will add integral disconnecting means to their fixtures to meet this rule. Now, if their is a switch, right there next to the ballast, it might actually be used. Other than that, no amount of code change will improve safety as 99 out of 100 service techs are going to hot swap that bad ballast. Not that I condone such practices, but reality is reality.

 

[LarryFine]

Re: Drastic change: 410.73 (G)

Is the typical 8' mono-pin 2-tube fixture with the circuit-interrupting end considered a disconnect? If so, a similar automatic "switch" could be built into a bi-pin fixture. I may have even seen one some time back.

 

[macmikeman]

Re: Drastic change: 410.73 (G)

I think it is a great Idea. I work on lots of 277 volt lights when it is controlled en mass by a lighting contactor. They want the ballasts replaced without turning off all the lights on the floor so as to not inconvienence themselves any. A simple switch located someplace in the fixture (outside of the wiring pan gets my vote) so I can turn off the power to the ballast before removing lamps and ballast cover tray is going to result in much less sweat on my brow.

 

[bphgravity]

Re: Drastic change: 410.73 (G)

Originally posted by macmikeman:
They want the ballasts replaced without turning off all the lights on the floor so as to not inconvienence themselves any.

Well that's just too bad. Noone's convienence is going to compromise my safety.

This change is nothing but a condation of unsafe working practices. The entire substantiation for this change was because electricians died or became injured for nothing more than not placing their job into a safe working condition, usually for the same reason above. It was too "inconvienent" for someone to have the power deenergized.

As long as the code adds requirements to protect the stupid people, I'm against it.

 

[iwire]

Re: Drastic change: 410.73 (G)

Originally posted by bphgravity:
As long as the code adds requirements to protect the stupid people, I'm against it.

Normally I agree with that basic policy but I disagree on this issue.

Why does the NEC require disconnects within sight at almost all hardwired equipment except light fixtures with ballasts that we know will need to be serviced?

Motors, appliances etc, we could say that the breaker for any of these is the disconnecting means but don't.

Even OSHA does not specifically prohibit changing ballasts live.

1910.333(a)(1)

"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.


Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.

When you are changing ballasts in the large warehouse stores of today killing a 277 lighting circuit puts a lot of people in the dark. Sure you can say that was a poor design from the start but that means noting to the service guy trying to change the ballasts.

I think this is a good change that will save lives and should have been in place long ago.

[ September 10, 2005, 10:39 AM: Message edited by: iwire ]

 

[cselectric]

Re: Drastic change: 410.73 (G)

Originally posted by bphgravity:

Originally posted by macmikeman:
They want the ballasts replaced without turning off all the lights on the floor so as to not inconvienence themselves any.

Well that's just too bad. Noone's convienence is going to compromise my safety.



As long as the code adds requirements to protect the stupid people, I'm against it.

So, if you were to go on a ballast change call, you would not only kill the circuit you were working on, trace out the circuit to find the other two lighting circuits on that multiwire and kill those as well? The intent here is not merely to kill the lighting circuit. It's to disconnect the grounded conductor, which carries quite the current on the average multiwire lighting circuit.

The real risk that this addresses is not live swapping of ballasts (which is a normal occurance), it's service techs getting lit up by loaded neutrals (also a common occurance.) Without this switching arrangement, a maintenance tech can believe he is totally safe because he killed a circuit, and then get blown off of his ladder by the grounded conductor. Personally, I expect a trained electrician to at least be aware of this condition, but how many ballasts are changed by Joe maintenance man?

 

[pierre]

Re: Drastic change: 410.73 (G)

Maybe I am wrong, but this is not going to cost a whole lot more (relatively speaking), and it will save the lives of some who are either forced by their employer or were not taught the proper way to do this.

Manufacturers will be picking this up - those who have stockpiled noncompliant type fixtures may have to be a little more concerned.

 

[cselectric]

Re: Drastic change: 410.73 (G)

Originally posted by LarryFine:
Is the typical 8' mono-pin 2-tube fixture with the circuit-interrupting end considered a disconnect? If so, a similar automatic "switch" could be built into a bi-pin fixture. I may have even seen one some time back.

Nope. Those disconnecting pins do nothing to kill power at the ballast, which is what is actually being required.

 

[jim sutton]

Re: Drastic change: 410.73 (G)

It shouldn't cost much more for the mfgs' but since they pretty much have a monopoly, they will make money.(they should)

 

[iwire]

Re: Drastic change: 410.73 (G)

Originally posted by cselectric:

Originally posted by LarryFine:
Is the typical 8' mono-pin 2-tube fixture with the circuit-interrupting end considered a disconnect? If so, a similar automatic "switch" could be built into a bi-pin fixture. I may have even seen one some time back.

Nope. Those disconnecting pins do nothing to kill power at the ballast, which is what is actually being required.

?

Any of these I have worked on do not have any power at the ballasts once both lamps are removed.

The hot is 'switched' by one lamp the 'neurtral' switched by the other lamp.

 

[don_resqcapt19]

Re: Drastic change: 410.73 (G)

Nope. Those disconnecting pins do nothing to kill power at the ballast, which is what is actually being required.

Actually on some fixture designs, the pin do disconnect the line conductor(s) from the ballast. In many cases however, they only disconnect one conductor and it might be the grounded conductor. If you have the type where both line conductors are disconnected from the ballast when the tubes are removed, I think that would comply with this rule. Look at this diagram. When the lamps are removed from the fixture both line conductors are disconnected from the ballast.
Don

 

[cselectric]

Re: Drastic change: 410.73 (G)

Based on that diagram, yes it would comply. But, to be honest, I've only seen the type that disconnect one conductor. Perhaps I spoke too soon.

 

[infinity]

Re: Drastic change: 410.73 (G)

Without this switching arrangement, a maintenance tech can believe he is totally safe because he killed a circuit, and then get blown off of his ladder by the grounded conductor.

This would not happen if the circuit were de-energized and the electrician were only working on the fixture ballast. The point in the multiwire branch circuit where to the neutral becomes a safety issue is the point at which it is shared with other circuits. A neutral at a fixture with a de-energized circuit conductor poses no safety threat.