Electric setup question

Hey all I've got a question about my electrical setup I think will work but just want to make sure.

My breaker box for the room I'm using has 2 switched and they both say 20. I checked to make sure I was in the right room before hand. Also it's 120 volts

My plan is to run 1 AC unit which says on the side 730 watts (it's 8000 btus) this will be on it's own outlet.

I'll be running a 400 watt ceramic metal hallide light. With a 485 cfm dayton blower rated at 1.35 amps. (both on the same plug in timer)

And lastly a water pump rated at 12 watts.

I'm thinking say 800 watts for AC, 400 for the light, 135 for the fan and 12 for the pump brings me to 1347 watts total.

Now my breakers say 20 amps (2000 watts right?) and at 1347 I'm below the 80% limit for the breakers in my room. Am I correct in this line of reasoning that I won't overpower the circuit? There is nothing else plugged into any outlet in the room.

Thanks for the help in advance...just want to make sure I'm right before starting anything.

alienrain said:

Hey all I've got a question about my electrical setup I think will work but just want to make sure.

My breaker box for the room I'm using has 2 switched and they both say 20. I checked to make sure I was in the right room before hand.

My plan is to run 1 AC unit which says on the side 730 watts (it's 8000 btus) this will be on it's own outlet.

I'll be running a 400 watt ceramic metal hallide light. With a 485 cfm dayton blower rated at 1.35 amps. (both on the same plug in timer)

And lastly a water pump rated at 12 watts.

I'm thinking say 800 watts for AC, 400 for the light, 135 for the fan and 12 for the pump brings me to 1347 watts total.

Now my breakers say 20 amps (2000 watts right?) and at 1347 I'm below the 80% limit for the breakers in my room. Am I correct in this line of reasoning that I won't overpower the circuit? There is nothing else plugged into any outlet in the room.

Thanks for the help in advance...just want to make sure I'm right before starting anything.

Click to expand...

That's too much power on that circuit. 110v has too much resistance to run that much on it, even with 20a breakers and 12 gauge wire. It just gets too hot.
Wire a seperate 20 amp breaker for your window ac. Then you'll never worry about it.

If your room has 2 separate breakers for it both at 20a why don't you just run the ac on the one and the rest on the other or split the loads 50/50 between the 2 instead of loading just the one. One breaker probably controls some lights and outlets for half the room, and the other for the other half. Just flip and find out what's what. I have a 15a and run a 400w hps, a big dehumidifier, 2 desk fans, and a big tall standing fan and have no problems at all with flicking or surge or anything. But if I had another breaker for my basement that wasnt dedicated for a fridge or washer then I'd def be using it. I just drilled a hole in my floor and draw power from another room. Wish I had more power in my house but can't afford to switch.

Also remember that usually when lets say my hps and dehumidifier go on the initial draw is usually higher at the start.

alienrain said:

I'm thinking say 800 watts for AC, 400 for the light, 135 for the fan and 12 for the pump brings me to 1347 watts total.
Now my breakers say 20 amps (2000 watts right?) and at 1347 I'm below the 80% limit for the breakers in my room. Am I correct in this line of reasoning that I won't overpower the circuit? There is nothing else plugged into any outlet in the room.

Click to expand...

It could work.. you have to consider that the ac will not be on all the time. Im using 1400W for my calculation and I only come up with 11.6 amps. I've done similar loads on a 20A breaker. For example a typical electrical space heater is around 1500 watts, and a 20A has no problem handling that. If you really want to be safe put the ac on another circut.

Whats most important is to "burn in" your setup. I turn everything on and check temps, air circulation, light pattern.. etc. Or even a weak breaker in your setup.. run it for a few days see if it works well.

However lets think about this for a second here..

If you plug in directly to a 20A breaker all the items and it does trip then then your plants will just be in the dark if it does trip. But if the lights and the ac are on a different circut and the light goes on and the ac does not and you dont have a high temp shutdown switch you could be asking for trouble.

2000w does not equal 20 amps. It's not linear like that.

I really appreciate the info, this kind of thing is something I want to get right because safety is first priority. Gotta be alive to smoke the shit right?

So do you use ohms law to figure out how many watts are actually running and then decide if you're within range? When do you know you've overpowered a circuit?

And if I've got 2 switches in a breaker box for 1 room, does that mean I have 2 circuits for the room? Thanks again for the help.