Current Limiting Device

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Hoyt

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Anyone aware of a current limiting device for a lighting circuit serving a pendant light. Not track lighting. Energy code related.

I see current limiting sub panels available, nothing for one circuit only.
 
Hoyt said:
Anyone aware of a current limiting device for a lighting circuit serving a pendant light. Not track lighting. Energy code related.

I see current limiting sub panels available, nothing for one circuit only.
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The term "current limiting" is a bit ambiguous. Please be more specific defining what the intent of CL is.
 
Our Electrical supplier use to carry what was called a bulb saver, was a small resistor you placed in the light bulb socket which lowered the voltage a bit , which would lower your light bill and make the bulb last longer.

Or you could place a rectifier in the circuit which will almost cut the current in half.

Ronald :)
 
Hoyt said:
Anyone aware of a current limiting device for a lighting circuit serving a pendant light. Not track lighting. Energy code related.

I see current limiting sub panels available, nothing for one circuit only.
Click to expand...

What do you mean in terms of current limiting? Depending on the type of lighting, the ballast is technically a current limiting device.

Do you need a TVSS, reactor, snubber, MOV? something else?
 
It appears that current limiters are not very common in many areas of the country. For an idea of what the OP is looking for, check out the link:

http://www.lightingcontrols.com/productcatalog/overview.asp?p=silverbullet

Of course, a current limiter panel like this is overkill for OP's application -- if I understand correctly, the idea is to find a small, stand-alone current limiter that could be used to limit the current to a single light fixture. Personally, I've only seen the panels (like the one in the link), or the current limiters that can ordered as an integral part of a lighting track.
 
My limited knowledge of current limiting has to do with various power supplies I have in my shop. They put out variable voltages either AC or DC and are current limiting. They have a current sensing circuit that limits the amount of output current no matter what the load impedance is. If you short the output the current drops to 0.
It is a very user friendly feature for clutz's like myself ;):D
 
ATSman said:
My limited knowledge of current limiting has to do with various power supplies I have in my shop. They put out variable voltages either AC or DC and are current limiting. They have a current sensing circuit that limits the amount of output current no matter what the load impedance is. If you short the output the current drops to 0.
It is a very user friendly feature for clutz's like myself ;):D
Click to expand...

That was a good explanation. From an electronic point of view I have one of those dual power supplies that does that. I just had to change hats from electric power distribution to electronics. With electrical stuff sometimes it's a challenge to make sure that everything is within its withstand and interrupting rating when a short circuit occurs. As such you often have to rely heavily on CL fuses and circuit breaker to coordinate with down stream devices and their series ratings.
 
JDBrown said:
Of course, a current limiter panel like this is overkill for OP's application --
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On the other hand I think it is perfect. The OP mentions he could use 10 amp branch circuit breakers to accomplish his goal.

I do not believe the NEC allows 10 amp branch circuit so running each 20 amp branch circuit through a current limiter panel should take care of it.



210.3 Rating. Branch circuits recognized by this article
shall be rated in accordance with the maximum permitted
ampere rating or setting of the overcurrent device. The rating
for other than individual branch circuits shall be 15, 20,
30, 40, and 50 amperes. Where conductors of higher ampacity
are used for any reason, the ampere rating or setting
of the specified overcurrent device shall determine the circuit
ra
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iwire said:
On the other hand I think it is perfect. The OP mentions he could use 10 amp branch circuit breakers to accomplish his goal.

I do not believe the NEC allows 10 amp branch circuit so running each 20 amp branch circuit through a current limiter panel should take care of it.
Click to expand...

The rating
for other than individual branch circuits....
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An individual branch circuit powers a single piece of equipment. Could you consider the track and its installed luminaires a single piece of equipment, since it is a (field assembled) unit connected to a single outlet on the house wiring?
 
GoldDigger said:
An individual branch circuit powers a single piece of equipment. Could you consider the track and its installed luminaires a single piece of equipment, since it is a (field assembled) unit connected to a single outlet on the house wiring?
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Branch Circuit, Individual. A branch circuit that supplies
only one utilization equipment.
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Some might, I would not.:)

To me a track lighting system with more than one fixture is clearly more than one piece of utilization equipment.
 
iwire said:
On the other hand I think it is perfect. The OP mentions he could use 10 amp branch circuit breakers to accomplish his goal.

I do not believe the NEC allows 10 amp branch circuit so running each 20 amp branch circuit through a current limiter panel should take care of it.
Click to expand...

I think you're mixing up this thread with another one: http://forums.mikeholt.com/showthread.php?t=154334
That's the one where the OP talked about using 10 amp branch circuits. Hoyt (OP for this thread) only needs a current limiter for one circuit. That's why I said I thought the current limiter panel would be overkill for his application. :cool:
 
templdl said:
That was a good explanation. From an electronic point of view I have one of those dual power supplies that does that. I just had to change hats from electric power distribution to electronics. With electrical stuff sometimes it's a challenge to make sure that everything is within its withstand and interrupting rating when a short circuit occurs. As such you often have to rely heavily on CL fuses and circuit breaker to coordinate with down stream devices and their series ratings.
Click to expand...

Templdl
wow, you fired a spark in my thinking! Yes CLF fuses which we work around in dist switchgear all the time limit the fault current (current limiting) to usually 1/4 cycle of the sine wave. I recall class J, Bussmann KTK control fuses with an IRC / IAC rating of 200KA, and power fuses with ratings.....??? Not much utility LV fault current is above 200,000A, at least in the SF CA bay area.
They all have their purpose to contol the electron flow during a fault :D
When people ask what I do, I tell them I'm in Electron Management, which pretty much covers it all :cool:

Tony
 
ATSman said:
Templdl
wow, you fired a spark in my thinking! Yes CLF fuses which we work around in dist switchgear all the time limit the fault current (current limiting) to usually 1/4 cycle of the sine wave. I recall class J, Bussmann KTK control fuses with an IRC / IAC rating of 200KA, and power fuses with ratings.....??? Not much utility LV fault current is above 200,000A, at least in the SF CA bay area.
They all have their purpose to contol the electron flow during a fault :D
When people ask what I do, I tell them I'm in Electron Management, which pretty much covers it all :cool:

Tony
Click to expand...

Gee Tony, I never heard it explained so well, electron management.
 
Is this a line voltage or low voltage pendant? When I used to design California Title 24 work we used to install low voltage track and would have to call out for a lot smaller transformer to get the lighting to comply with Title 24. If this is a low voltage pendant, then you could install a small transformer and it should comply. But that was 7 or 8 years ago.
 
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