How many lights on 20 amp circuit?

legotech7 · Apr 12, 2015

Hello everyone, I need to know how many lights I can run on a 20 amp circuit. My plan is to hang 10 florescent bulb fixtures with 2 T8 bulbs each at 32 watts for each bulb. The 20amp circuit used solely for the lights, but might add some more in the future, ( outside lighting and the such ). The ballast's would be the electric start types, if that makes a difference. Would that many lights be ok for the 20 amp circuit?

Thanks all......

jonjon1 · Apr 12, 2015

For lights 1920 watts

I did 20a in my storage building, needed 20 a switches and 20 fixtures, 12-2, it wasnt cheap, especially them 3 ways, they were like $8 each, and we needed a TON of them, I think the regular ones are $1.50 each..

And I think its against code to do this in a non commercial application, you would be stuck with 15a circuit, still 1800 watts at 80% is 1440 so if that was 75 watt lights, you could put 19 of them...

most electricians in a residential setting around here go 12 fixtures per 15a circuit...

Justanoldguy · Apr 12, 2015

jonjon1 said:
most electricians in a residential setting around here go 12 fixtures per 15a circuit...

People talk about " around here" but never say where "around here" is

Are you in NZ or UK or ? :lol_hitti

alfredeneuman · Apr 12, 2015

jonjon1 said:
And I think its against code to do this in a non commercial application, you would be stuck with 15a circuit, still 1800 watts at 80% is 1440 so if that was 75 watt lights, you could put 19 of them...

Nothing in the Code prohibits this

cybrdyke · Apr 12, 2015

legotech7 said:
Hello everyone, I need to know how many lights I can run on a 20 amp circuit. My plan is to hang 10 florescent bulb fixtures with 2 T8 bulbs each at 32 watts for each bulb. The 20amp circuit used solely for the lights, but might add some more in the future, ( outside lighting and the such ). The ballast's would be the electric start types, if that makes a difference. Would that many lights be ok for the 20 amp circuit?

Thanks all......

With "normal" ballasts, you are only at 590 watts, only about 1/3 of the maximum.
Good luck
CD

alfredeneuman · Apr 12, 2015

The 2 lamp ballasts themselves draw .8 amp, or 96 watts.

10 of them would be OK on either a 15 or 20 Amp circuit.

With a 15 amp circuit you'd be able to install another 5 fixtures and not be overloaded.
With a 20 amp circuit you could install another 10 for a total of 20.

Lighting loads are figured at 80% of the breaker rating.

cybrdyke · Apr 13, 2015

alfredeneuman said:
The 2 lamp ballasts themselves draw .8 amp, or 96 watts.

Maybe you looked at a 4 lamp ballast? Or an 8' ballast?

Advance ICN2P32N draws .49 amps and 59 watts when running 2 F32T8 lamps.
CD

alfredeneuman · Apr 13, 2015

cybrdyke said:
Maybe you looked at a 4 lamp ballast? Or an 8' ballast?

Advance ICN2P32N draws .49 amps and 59 watts when running 2 F32T8 lamps.
CD

You are right of course, but I should explain my reasoning.
That's a dual voltage ballast. Normal household fluorescent fixtures from the big box stores don't have the dual voltage ballasts. You'd have to go to supply house to get them.

I was doing by the figuring by the REB-2P32-SC which is a 2 lamp ballast that draws .8 amp

http://www.homedepot.com/p/Philips-...7064?cm_sp=BazVoice-_-QA_PSVP-_-202977064-_-x

EDIT: I checked one of the Lithonia fixtures from HD that I had pulled the Accu-Pro ballast out to convert to 277V and it draws .49 amp, by gosh.

You could put 25 of these on a 15 amp circuit, or 32 on a 20 amp.
I guess the only way to answer this question is to check the individual ballast.

michiganman18 · Apr 13, 2015

Should be fine. No considerable draw there if its just for lights.

jonjon1 · Apr 13, 2015

alfredeneuman said:
Nothing in the Code prohibits this

Like I said I was not sure, I remember a conversation when I was having my 20a lighting done, that the residential light fixtures did not have heavy enough wire to be on a 20a breaker, because on the strong of 20a lighting I wanted to include the bathroom light, I ended up having to buy a different fixture that was special ordered and again EXPENSIVE.

After I did it, I figured I could have ran 2 15a lines with less trouble and for less money...

jonjon1 · Apr 13, 2015

Justanoldguy said:
People talk about " around here" but never say where "around here" is

Are you in NZ or UK or ?

I am in the US :rocker:

Justanoldguy · Apr 13, 2015

jonjon1 said:
I am in the US

Pretty much figured that one.

Problem here is every state and every area of every state seems to have their own rules.

So much simpler to get a right answer when people put their location in their profile.

Agreed?

legotech7 · Apr 13, 2015

Location is in the profile... North Caroilina USA..................

legotech7 · Apr 13, 2015

Thanks guys, I did a little home work, I think I'll be OK with my original inquiry.. 10 light fixtures on a 20amp circuit at 32 watts per bulb... and then some. Now I just have to figure out my lay out.......

Thanks again.......

jonjon1 · Apr 13, 2015

Justanoldguy said:
Pretty much figured that one.

Problem here is every state and every area of every state seems to have their own rules.

So much simpler to get a right answer when people put their location in their profile.

Agreed?

I would agree, but what if the member is an international man of mystery, then advertising said location would be a farce...

GuyllFyre · Apr 13, 2015

VxA=Watts

115VACx20A=2300W

GuyllFyre · Apr 13, 2015

Oh, just for the fun of it, I took my $12 wattometer thingie and plugged it into a standard dual tube 40W T12 shop light and saw an average of 62 watts per fixture.
2300W/62W=37 fixtures (approx)

Norcal · Apr 13, 2015

GuyllFyre said:
VxA=Watts

115VACx20A=2300W

120 volts is the correct unit when doing calculations.

GuyllFyre · Apr 13, 2015

Norcal said:
120 volts is the correct unit when doing calculations.

Only if you haven't measured your actual supplied voltage.
Mine is a very stable 115.

justsam · Apr 13, 2015

GuyllFyre said:
VxA=Watts

115VACx20A=2300W

Inductive lighting loads are not to exceed 80% of breaker, so using your numbers max of 1840 Volt/Amperes.

He is no where close to having an issue, regardless.

legotech7 · Apr 13, 2015

Ok, researching some of the light fixtures from the big box stores, I noticed most of the fixtures are wired with their own standard type plugs. I wanted to hard wire the lights with two separate switches, so I can turn on just the one side witch will have five lights and only turn the other if I need them. Can I just remove the plugs and hard wire into them? I wanted to do this in series, ( daisy chain if you will ) . I'm a bit confused as how to wire them.. Sorry for all the questions, very much a nube at this...... While I'm asking, what type of bulb is best for lighting. The lights will hang at about 9 feet off the floor. They have cool white, day light and so on, confused about that also...

Thanks again........

Charles (in GA) · Apr 13, 2015

You need to buy better fixtures. The ones with the plugs are UL listed with the plug and should not have the plug removed. In addition most of those are chain hung, and if you read the fine print, they must be chain hung, its again part of the UL listing, and is due to heat generated by the ballast.

Even with surface mount fixtures you are better off to set them off the ceiling surface with spacers at the mounting points, for cooling.

Buy fixtures that are designed to be hardwired.

Charles

MattN03 · Apr 13, 2015

I've just wire a duplex outlet and then have an outlet for two lights from a box store. If it fails, it's a simple matter of unplugging and replacing.

laser3kw · Apr 14, 2015

I wanted to do this in series, ( daisy chain if you will ) .

I understand what you mean, but actually you are wiring them in parallel.
Also follows Charles (in GA) advice. The fixtures with plugs aren't what you want if you are going to "hardwire" / conduit install. There are multiple threads here about what others have use and which big box store carries them. I used Lithonia T8 tandam fixture like these:
T8 fixtures link
But they are harder to mount if you are by yourself. You can do it, you have to be creative on how to hold the fixture to the ceiling while you screw it up. 4 foot twin tubes are easier to handle.
If you wish to hang them, then yes you can use the plug type. But then you must run conduit and receptacles to each fixture location.

MattN03 · Apr 14, 2015

I used 4' quad fixtures from Lowe's on my last few fixtures and like them a lot.

legotech7 · Apr 14, 2015

Yes in parallel, as for hanging them , this whole project I have dome by myself. Suffering from RA and doing them on my good days..But anyway,...Doing this on a budget, the hard wired fixtures are a bit more expensive. If I wire them in parallel, can I just tap into one juction box for each side, and wire it that way? would I need to add more J boxes? Here's a layout, a bit rough, but it is what it is.... please feel free to add to it or any other suggestion you might have. Obviously the light switches are coming from the source panel and so on, so my routing from there on, is where I'm a little leery on. I hope this all makes sense.

Once again, Thank you all.......

GuyllFyre · Apr 14, 2015

justsam said:
Inductive lighting loads are not to exceed 80% of breaker, so using your numbers max of 1840 Volt/Amperes.
He is no where close to having an issue, regardless.

LOL.
Just plug things in until the breaker pops then remove one. :lol_hitti

How many lights on 20 amp circuit?

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