How many 105W CFL's per circuit??

[Zogman]

It's time to get my electrical laid out in my garage build and I've chosen 105W CFL's for my lighting. I'm trying to lay out my wiring diagram for each circuit and I'm a bit puzzled on my calculations.

I'm thinking 15 amp circuits. I have a bunch of 14/2 wire available to me.

So I pull up a watts to amps calculator and it's asking for power factor. I've never heard of that. Googled the **** out of it and more or less I see that CFL's have a power factor of .5 which is a poor rating. Does this sound right?????

So I have 7 CFL's in one section, and 9 in each of the other 2 sections. FYI, 2500 sq ft garage.

I was hoping to run (3) 15 amp circuits using the 14/2 wire.

After doing the math using the .5 power factor, the 7 lights rates at 13.3 amps using the .5 power factor. The 9 lights rate at 17.1 amps.

I don't want to be a cheap ******* but I want to save where I can.

Am I doing the math correctly because it looks like I need to go to 20 amp circuits with 12/2 wire for the 9 light circuits.

Any thoughts would be helpful.

Thanks

Z

 

[awdblazer]

you need the ballast rating that should be on the light itself and use that instead of the wattage rating

 

[Zogman]

The bulb says "Self - Ballasted" and it also says 1600mA. How do I compute using the milliamp rating? Thanks

 

[Zogman]

btw Blazer.... not sure if you are a hockey fan, but game on Thursday!!! Ill be at the game on Saturday.

 

[cybrdyke]

It's time to get my electrical laid out in my garage build and I've chosen 105W CFL's for my lighting. I'm trying to lay out my wiring diagram for each circuit and I'm a bit puzzled on my calculations.

I'm thinking 15 amp circuits. I have a bunch of 14/2 wire available to me.

So I pull up a watts to amps calculator and it's asking for power factor. I've never heard of that. Googled the **** out of it and more or less I see that CFL's have a power factor of .5 which is a poor rating. Does this sound right?????

So I have 7 CFL's in one section, and 9 in each of the other 2 sections. FYI, 2500 sq ft garage.

I was hoping to run (3) 15 amp circuits using the 14/2 wire.

After doing the math using the .5 power factor, the 7 lights rates at 13.3 amps using the .5 power factor. The 9 lights rate at 17.1 amps.

I don't want to be a cheap ******* but I want to save where I can.

Am I doing the math correctly because it looks like I need to go to 20 amp circuits with 12/2 wire for the 9 light circuits.

Any thoughts would be helpful.

Thanks

Z

It's pretty common for CFL's to have low power factor, in the .5 range. In most residential applications, this doesn't matter much, but it does skew the numbers somewhat and not in a positive fashion.
Normally, the manufacturer tells you the information. I searched the Eiko website and couldn't find it. Eiko is one of the bigger manufacturers of this item. Interestingly, they tell you the power factor for nearly every single item they make, except these CFL's. That leads me to believe that they are very low power factor and they dont want to print that info.
They also dont publish the amp draw per lamp, which also makes me think it's a very low PF.
Good luck
CD

 

[Trey T]

The bulb says "Self - Ballasted" and it also says 1600mA. How do I compute using the milliamp rating? Thanks

What lighting fixture are you using? is the typical porcelain medium base 300W (120V)?

If you want to design your lighting setup purely on the load of the CFL you picked and using 300W fixture, you have to be aware that your design is for max load of 1.6A (1600mA) per fixture. For proper operational purposes, you should label your fixture for max ACTUAL load of 192W so the next person would not load anything higher than 1.6A. BE AWARE THAT IF YOU GET PERMIT FOR THIS DESIGN, YOU'RE LIKELY TO FAIL, even though it's safe design for this specific purpose.

To answer your question, you can load maximum of seven of those CFLs per 15A. Or ten CFL per 20A line.

 

[Zogman]

One more related question folks. I have 3 new outdoor flood fixtures that were given to me that I want installed outside. They are 240V fixtures and the bulbs are 1500T3Q/CL/240V. I can't find anything on the power value on these Halogen bulbs. These will rarely be used but they should brighten my driveway up a bunch to wash my car and such. I want to put them on 1 circuit with 3 separate switches on a 20 amp circuit. Am I OK? Thanks

Zoli

 

[patrickoneal]

One more related question folks. I have 3 new outdoor flood fixtures that were given to me that I want installed outside. They are 240V fixtures and the bulbs are 1500T3Q/CL/240V. I can't find anything on the power value on these Halogen bulbs. These will rarely be used but they should brighten my driveway up a bunch to wash my car and such. I want to put them on 1 circuit with 3 separate switches on a 20 amp circuit. Am I OK? Thanks

Zoli

Those lamps are 1500 watts. 1500 watts at 240V is 6.25 amps, for a total of 18.75 amps. You're only supposed to load a breaker to 80% of it's capacity for a continuous load. 80% of 20A is 16A, so that's not going to work.

As for your CFLs... if they're in porcelain keyless fixtures be careful of the lamp selection. We put a bunch in our shop at work, all hanging upside down in porcelain fixtures. Most of them have failed pretty quickly, because the vent for the ballast is in the "top", and no heat can escape. This cooks the ballast. Make sure whatever you have is rated to be installed upside down.

 

[theoldwizard1]

So I have 7 CFL's in one section, and 9 in each of the other 2 sections. FYI, 2500 sq ft garage.

Each one of those bulbs is equivalent to a 400W incandescent. What the heck do you need 10,000 watts of light for ? Making ***** movies or growing "vegetables" ?

I was hoping to run (3) 15 amp circuits using the 14/2 wire.

Use the 14/2, but also buy breakers that are specifically designed for florescent bulbs.

 

[Rusty Bumper]

Use the 14/2, but also buy breakers that are specifically designed for florescent bulbs.

What are the breakers that are specifically designed for fluorescent bulbs? Would thess be switch duty (SWD) breakers? Or something different?

 

[theoldwizard1]

What are the breakers that are specifically designed for fluorescent bulbs? Would thess be switch duty (SWD) breakers?

Square D QO-HID. Yes, they are rated for SWD.

 

[Zogman]

Each one of those bulbs is equivalent to a 400W incandescent. What the heck do you need 10,000 watts of light for ? Making ***** movies or growing "vegetables" ?


Use the 14/2, but also buy breakers that are specifically designed for florescent bulbs.

I did a calculation based on Veno's thread a while back on how many lumens per cubic feet. I rigged up 7 of the lights in my main work area and the lighting is perfect so I'm taking that calculation to the rest of the shop. But it's good to know I'll be able to film a ***** if I need to!!!

Thanks for the tip on the breaker.

 

[Zogman]

Those lamps are 1500 watts. 1500 watts at 240V is 6.25 amps, for a total of 18.75 amps. You're only supposed to load a breaker to 80% of it's capacity for a continuous load. 80% of 20A is 16A, so that's not going to work.

As for your CFLs... if they're in porcelain keyless fixtures be careful of the lamp selection. We put a bunch in our shop at work, all hanging upside down in porcelain fixtures. Most of them have failed pretty quickly, because the vent for the ballast is in the "top", and no heat can escape. This cooks the ballast. Make sure whatever you have is rated to be installed upside down.

The fixtures are hanging barn shade fixtures. They are porcelain fixtures rated at 300 watts for incandescent bulbs. Hope this will be sufficient.

 

[patrickoneal]

The fixtures are hanging barn shade fixtures. They are porcelain fixtures rated at 300 watts for incandescent bulbs. Hope this will be sufficient.

The fixtures are probably fine... I was more worried about your bulbs. Do you have a link to your CFL bulbs?

 

[Zogman]

Here is the link Patrick. Let me know what you think.
https://www.1000bulbs.com/product/8256/FC105-S50OD.html
Thanks
Z

 

[patrickoneal]

Here is the link Patrick. Let me know what you think.
https://www.1000bulbs.com/product/8256/FC105-S50OD.html
Thanks
Z

The spec sheet there shows them installed in pendant fixtues, hanging down. You should be OK.

Like I said, we had some in our shop that didn't last very long because the vent to let heat out of the ballast was at the top, and we had them inverted, so the ballasts burnt up. I assume yours have some other means of ventilation, as the spec sheet specifically shows your application.

 

[Zogman]

Thanks Patrick. Do you think it would be a good idea to drill (3) 1/4" holes near the top of the pendant to vent the heat up and away??? Just thinking this might help a bit just in case. Thanks again.

 

[nine4gmc]

Pick up a "Kill-a-watt" meter and measure one, you will know for sure how much they pull and can figure from there how many per circuit. The meter is cheap and handy as hell, I used it to figure out my shop refrigerator, computer plus accessories, stereo, fan and light could all operate safely within spec on a circuit without chance of overloading. Also lets me know what machines to run on what circuit so it stays balanced when more than one thing is on.