Electrical / 15 Amp Circuit Question

Thank you in advance for your help and please excuse my lack of knowledge or if my terminology isn’t accurate.

I am hoping someone can help me answer a question or two about running some Quantum boards using Meanwell drivers and I want to make sure I’m not overloading a 15 Amp circuit, as well as see how much wattage or amps I have left for other electrical devices on the same 15A circuit.
I have 2x HLG-320H-48AB and 1x HLG-240H-48AB Drivers- all with dimmers and I am running all three on the same 15amp circuit. I have attached a picture of each of them for review and accuracy.
There’s so much information online but I’m not finding a definitive answer that I understand. I’m quite new to this, clearly.
One explanation said take the total watts of the lights which is around 800-880 watts if running all max brightness (or less when they’re dimmed I assume, but for the sake of this scenario let’s assume the max 880), and then divide by the voltage which I believe is 120. That comes out to 7.33 amps. And if I understand correctly, I should keep it 20% below the max which would be 12 available amps. Therefore that would leave approximately 4.67 amps for other electrical devices - if this way of calculating is even correct...

I would sincerely and greatly appreciate any input and help! Thank you guys!

Yes. Watts / Volts = Amps

Yes. 12 amps is usable on a 15 amp feed.

If you were to overload the circuit the breaker will trip and nothing will be harmed.

If the circuit is pushed right to the limit it may trip if the breaker panel gets hot (summer in a garage for example).

I also spoke to an electrician at work. He said on a 15a breaker 1300watt is the limit. A 1500w heater is allowed but shouldnt be run constantly. Hooe this helps. I wm trying to figure out how to run my leds on 20a 220v breajer when i only have 110v cord?

berulakide said:

I also spoke to an electrician at work. He said on a 15a breaker 1300watt is the limit. A 1500w heater is allowed but shouldnt be run constantly. Hooe this helps. I wm trying to figure out how to run my leds on 20a 220v breajer when i only have 110v cord?

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Thats incorrect. You can pull up to 1440 watts on a 15 amp 120v feed. 1300 watts is a safe number.

Your 110v cord will handle 240 volts. The plug is different is all. You can get a 240v cord that has the proper plug.

Watts / volts = amps
Amps times volts = Watts

So. If your voltage is 120v on a 20amp circuit. Then you got 2400 watts. At 110 volts you would have 2200 watts.

For those who don’t want to do math or don’t have volt meters.... you can put 1500watts on a 15amp circuit
And
2000watts on a 20amp circuit.

With a little to spare.

DeepWaterDean said:

Watts / volts = amps
Amps times volts = Watts

So. If your voltage is 120v on a 20amp circuit. Then you got 2400 watts. At 110 volts you would have 2200 watts.

For those who don’t want to do math or don’t have volt meters.... you can put 1500watts on a 15amp circuit
And
2000watts on a 20amp circuit.

With a little to spare.

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You have to account for the fact that the circuit breaker will trip at 80%.

So a 20 amp 220v circuit I should have no problems with 2520w should I? If it was 120v it wouldnt be enoigh. Ir should I just have 2 or 3 15a 120v? I figured run all lights off rhe 20a 220v and evrything else I need off 15a 110v plug.

Renfro said:

You have to account for the fact that the circuit breaker will trip at 80%.

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No. It won’t. Totally disagree

Check your NEC Handbook again apprentice. If I remember correctly it was 384-16 that covered that. Temperature ratings also come into play, a breaker may trip before 80% if it's hot or a little after 80% if it's really cold. The 80% loading of a breaker rule was eliminated in the 2002 code because calculations required to properly size wire and devices properly compensate and make the 80% rule no longer needed. (meaning the OCPD is designed with the 80% load rating internally)

Laymans terms: I have one 15 amp feed in my home that when my PC is running with the AC on it's right at 11.8 - 11.9 amps according to my meter, if it gets hot in the garage where the panel is (like 100 outside) then it will trip. If I add a little load it will trip.

Renfro said:

Check your NEC Handbook again apprentice. If I remember correctly it was 384-16 that covered that. Temperature ratings also come into play, a breaker may trip before 80% if it's hot or a little after 80% if it's really cold. The 80% loading of a breaker rule was eliminated in the 2002 code because calculations required to properly size wire and devices properly compensate and make the 80% rule no longer needed. (meaning the OCPD is designed with the 80% load rating internally)

Laymans terms: I have one 15 amp feed in my home that when my PC is running with the AC on it's right at 11.8 - 11.9 amps according to my meter, if it gets hot in the garage where the panel is (like 100 outside) then it will trip. If I add a little load it will trip.

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You can spout code all you want. I’m a sound engineer who works with 100,000watt systems every single day. I’ve planned whole festivals power plans for multi stages and vender rows. What I’m saying is correct and backed up by a decade of exp and millions of dollars riding on me being right about the generator size we need at multi locations.

I hope when your sizing generators you are specing prime power. anyways I will agree to disagree.

We had a client just like you in Kansas City about 20 years ago, they bought a generator for their productions and when the main act came on it would scram. They didn't spec prime power and the poor generator had had enough and when they cranked up the power for the main act the poor generator said fuck it. Was funny, you could hear it bog down, not make cycles/revs and the controller would bail.

Renfro said:

We had a client just like you in Kansas City about 20 years ago, they bought a generator for their productions and when the main act came on it would scram. They didn't spec prime power and the poor generator had had enough and when they cranked up the power for the main act the poor generator said fuck it. Was funny, you could hear it bog down, not make cycles/revs and the controller would bail.

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I’m sorry you had a shit fest once. My company handles Metallica. Fuck you!

DeepWaterDean said:

I’m sorry you had a shit fest once. My company handles Metallica. Fuck you!

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Metallica hasnt been any good for over 30 years. Kick rocks, kid

natureboygrower said:

Metallica hasnt been any good for over 30 years. Kick rocks, kid

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Weather you like the music has nothing to do with the level of production that’s needed to pull off the show. I deal with big power every day and I’m just trying to help a grower with ohm’s law basic power. Your house has shit breakers that trip after 12amps? That’s not the way it should be working. I’m dealing with 20 amp stage drops all day long and they don’t trip at 12amps draw that’s for sure.

DeepWaterDean said:

Weather you like the music has nothing to do with the level of production that’s needed to pull off the show. I deal with big power every day and I’m just trying to help a grower with ohm’s law basic power. Your house has shit breakers that trip after 12amps? That’s not the way it should be working. I’m dealing with 20 amp stage drops all day long and they don’t trip at 12amps draw that’s for sure.

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I believe hes talking about a 15amp breaker? Yes, I agree. If a 20a breaker trips at 12amps, something is wrong. I was taught the same as Renfro, 80% draw is what is recommended. I always error on the side of overkill

A 20 amp should handle 16 amps continuous draw. A stage drop may be classified under code differently, id have to check but I suspect not. either way you go, this isn't a stage application and I am very familiar with the residential and commercial power distribution systems. We are also talking continuous load, a 20 amp breaker will take a quick surge of say 18 amps but continuous rating is 80% or 16 amps.

I think this guy is getting pissed.

Some really good info here. Had me scratching my head for a second because I know I'm running my breakers above 80% load. Anyways I think you both are right..

Probably best to just assume 80% rated breakers and go from there.