Fixtures Per Circuit

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infinity

infinity

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As Tom stated the driver input current is .51 amps @120 volts so forget the watts/amps. Your calculation appears correct.
 
infinity

infinity

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I checked your numbers and get 31 drivers.
20 amps * 80% = 16 amps
31*.51 amps = 15.8 amps
 
G

gar

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171011-1622 EDT

A 9,5 W Phillips LED bulb may have a peak inrush current of 6 A measured with a 2 ohm resistor. This inrush is very short. Damped oscillation lasts about 1.5 milliseconds.

What you switch or control this circuit with may be the limiting factor rather than the wire or breaker.

What kind of inrush current your drivers have needs to be known. Knowledge of just a steady state load current is possibly insufficient. Note, 30*6 = 180 A. A single 100 W incandescent can have a peak inrush of 16 A. Would you put 16 or more of these bulbs on one circuit, and switch them simultaneously?


.
 
M

mstrlucky74

Senior Member
Location
NJ
gar said:
171011-1622 EDT

A 9,5 W Phillips LED bulb may have a peak inrush current of 6 A measured with a 2 ohm resistor. This inrush is very short. Damped oscillation lasts about 1.5 milliseconds.

What you switch or control this circuit with may be the limiting factor rather than the wire or breaker.

What kind of inrush current your drivers have needs to be known. Knowledge of just a steady state load current is possibly insufficient. Note, 30*6 = 180 A. A single 100 W incandescent can have a peak inrush of 16 A. Would you put 16 or more of these bulbs on one circuit, and switch them simultaneously?


.
Click to expand...

Says in rush current is less than 2 amps
 
G

gar

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Location
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EE
171011-2448 EDT

With a Costco 4 foot two tube 36 W shop light I recorded one inrush pulse at about 10 A for about 2 milliseconds. This is closer to the power of one of your drivers. Still using 2 ohms to measure current.

You really need to make actual measurements on your driver.

With such data, then it becomes necessary to figure out how that may affect your application. This is the hardest part. Note that peak pulse input current is a function of how fully discharged is the driver input capacitor and where in the AC cycle power is applied.

.
 
G

gar

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Location
Ann Arbor, Michigan
Occupation
EE
171012-1037 EDT

Ingenieur:

The Costco pulse I measured was fairly close to a rectangular pulse of about 10 A and duration of 2 milliseconds. I did not run a controlled experiment where I could define the turn on point. I simply used a plug as the switch, and tried enough times with random turn on to get a reasonably large pulse.

If I had a 300 A pulse like this I think it would trip a QO20. The energy imparted to the breaker will determine if it trips or not. If not on the first pulse, then quite likely on a second or third pulse. Note a QO is thermal-magnetic in its trip mechanism.

If you do not actually trip a breaker the latch mechanism may move some, stay put because of friction, and trip easier on a subsequent pulse.

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Fulthrotl

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gar said:
171011-2448 EDT
You really need to make actual measurements on your driver.
.
Click to expand...

+11eventeen on that.

to the OP:

this is an eco driver. digital, addressable, runs on a lutron
eco system. grafik eye, quantum, etc. requires an interface,
supporting 64 devices. can NOT be commingled with 0-10 v.
controls on the same bus. a common error. lutron's 0-10
driver looks almost the same to a lot of electricians. trust me.

how much it draws depends on what it's hooked to. i've seen
this driver on fixtures drawing anywhere from 3 watts to 40 watts
per fixture.

so your question is not able to be resolved with your information.
what fixture is it on? case in point. observe this fixture below:

lights.jpg

these are independent fixture heads. each one draws about 4 watts
each, measured with a wattmeter. PER HEAD. here is the fun part.
each fixture has TWO of those eco drivers, so each light can be controlled
independently.

so, as the EE didn't pay attention to this fact, his design allowed
for one eco single loop control panel, controlling 64 devices.
he ended up needing four single loop controllers, or two double loop
controllers.

but it gets better. the fixtures were tied together using MC cable with
control wires in them, as is common practice. you can put far more
devices on that 20 amp circuit than you can logically address with one
controller. you can put them in an inaccessible hardwood ceiling, stained.
you can cry sad tears when you have to fix it.

you can put 240 of those luminaries on a single 20 amp circuit. then, you
can split it eight times to get it to work. you will have 480 addressable
drivers. let's hope the ceiling is accessible.

you really need to understand the systems you are working with before
designing for them....
 
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