# how many watts on one outlet?



## basement nirvana (Mar 13, 2010)

I am designing my flower room and re doing the electrical. I will have 2 seperate outlets on different 20 amp circuits. Can I put 2 1000watt HPS lights on one of these circuits (4 lights total on 2 circuits). Anyone running 2 1000W lights on the same house 120volt circuit? And it has 14 gauge supply wire.


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## Silky Shagsalot (Mar 13, 2010)

basement nirvana said:


> I am designing my flower room and re doing the electrical. I will have 2 seperate outlets on different 20 amp circuits. Can I put 2 1000watt HPS lights on one of these circuits (4 lights total on 2 circuits). Anyone running 2 1000W lights on the same house 120volt circuit? And it has 14 gauge supply wire.


lol, so you're re-doing the electrical and you can't answer this question? i'm sorry, i don't mean to be rude, but i don't understand how you can't figure this... let me see if i remember this... you divide the total wattage by the volts to get the total amps. and i think you don't want to be within 80% of the total amps of the circuit. i'm not a big electrical guy though.... i'm sure someone will step in here and give a better answer.


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## basement nirvana (Mar 14, 2010)

Yes, I did that calculation and realize I am within the limit. I was more curious as putting 2000 watts on a surge protector but I have found heavy duty rated ones so now worries there. I just wanted re assurance with the electrical...I want to do everything right!


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## Hotwired (Mar 14, 2010)

Dude leave some room to spare on the outlets.

Usually a small bedroom will be 20 amps max. This includes ALL outlets for the room itself. 20 amps max.

So each 1000 watt light is about 11 - 12 amps with ballast use. Maybe more.

Remember the rule for each outlet is 15% extra left over to be safe.

So if you have a 20 amp room you should only use 17 of those amps to avoid a fire issue.

Get yourself on a 30 amp outlet for those 2 lights. You will have room to spare for a few fans.


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## IAm5toned (Mar 14, 2010)

a small bedroom is 15 amps. any electrician with his head not up his ass would never waste a 20 amp breaker on a bedroom circuit.

rule of thumb- 1440w of grow equipment per _dedicated #14awg cable, _15 amp breaker, max.
1920w of grow equipment per _dedicated #12awg cable, _20 amp breaker, max.
2880w of grow equipment per _dedicated #10awg cable, _30 amp breaker, max.

those wattages are good for 120v only. it changes if your going to go 240.

and ps- those numbers are factored for continous duty operation. dont play with them. i know you can get more wattage out of the breakers, but if you try to run them with higher wattage than i posted above, the breaker will heat up and trip after a cpl of hours.
stick with those numbers and you cant go wrong.


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## basement nirvana (Mar 14, 2010)

So I was considering putting 2 1000 watt lights on the one 20 amp breaker but it is just too close for comfort, I was more concerned with the 14 gauge wire. I have decided to run another conduit line into the room from another room/circuit. When it is all finished I will have 3 separate outlets on 3 separate circuits...it's gonna be sweet. Thanks guys!


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## Silky Shagsalot (Mar 14, 2010)

see, i knew you'd get some answers. that brings up another question. can you just change out the circuit to a 30 amp one, or do you need to put in a heavier gauge conduit too?


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## basement nirvana (Mar 14, 2010)

from what I understand it comes down to the capacity of the wire. 
http://www.cerrowire.com/default.aspx?id=46


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## roka (Mar 14, 2010)

basement nirvana said:


> So I was considering putting 2 1000 watt lights on the one 20 amp breaker but it is just too close for comfort, I was more concerned with the 14 gauge wire. I have decided to run another conduit line into the room from another room/circuit. When it is all finished I will have 3 separate outlets on 3 separate circuits...it's gonna be sweet. Thanks guys!


14 gauge wire is only good for 15 amp circuit. 20 amps uses 12 gauge. Sounds like someone changed the bedroom 15amp circuit breaker to a 20amp breaker after the fact. Definitely not a safe situation.


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## Stoner McBoner (Mar 14, 2010)

This thread is more important than you guys think. Please, don't bash guys for asking dumb Q's. Any question about electricity is a good one. With people running to the grow shop buying "things that plug in", I think some more education is needed.


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## CLOSETGROWTH (Mar 14, 2010)

Stoner McBoner said:


> This thread is more important than you guys think. Please, don't bash guys for asking dumb Q's. Any question about electricity is a good one. With people running to the grow shop buying "things that plug in", I think some more education is needed.


I agree..

Spread the knowledge, and be cool to each other... sheesh.


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## UNICRONLIVES (Mar 14, 2010)

you can only run about 1700 watts thru 12-2 wire and definitely not 14 gauge!! better step up to 12-2 at the least..or 10-2 if you dont want to let the smoke out of the wire!!!! and your pushing it for 1 single 20 amp breaker!! the 1k pull bout 9-10 amps at start up!! better make another plan!! its not worth riskin lives!!


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## OZUT (Mar 15, 2010)

You gotta change the wire...it you have a 14 gauge wire and a 30 amp breaker, then you're asking for trouble....what will happen is your wire will get over loaded but your breaker won't trip because it's waiting for 30 amps to trip...what happens is it keeps supporting the ampage being pumped and in return your wire starts to burn....ultimately - FIRE!!!....You want your breaker to correctly support your wire....What you could do is run 1 or 2 of the lights to an outlet in another room with an extension cord


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## IAm5toned (Mar 15, 2010)

IAm5toned said:


> a small bedroom is 15 amps. any electrician with his head not up his ass would never waste a 20 amp breaker on a bedroom circuit.
> 
> rule of thumb- 1440w of grow equipment per _dedicated #14awg cable, _15 amp breaker, max.
> 1920w of grow equipment per _dedicated #12awg cable, _20 amp breaker, max.
> ...


edited for clarity. i have incorporated the wire sizes for you.


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## mrmadcow (Mar 15, 2010)

IAm5toned said:


> a small bedroom is 15 amps. any electrician with his head not up his ass would never waste a 20 amp breaker on a bedroom circuit.
> 
> rule of thumb- 1440w of grow equipment per _dedicated #14awg cable, _15 amp breaker, max.
> 1920w of grow equipment per _dedicated #12awg cable, _20 amp breaker, max.
> ...


also note that most outlets are rated for 15 amps so even if you run 10 gauge wire(and a 30 amp breaker) to a single 15 amp outlet and plug a powerstrip into it,you cant put 20 amps of equipment on it.


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## sixstring2112 (Mar 15, 2010)

bottom line-- 14 gage should not be used in a real grow room (growers with 1000 watt lights). and i dont recomend 2 1000 watt lights on 1- 20 amp breaker.if you have the cash to run 2 1000 watt lights in your grow room spend the extra money and put in a seperate 220 line just for lights on its own breaker. 220 is better for your ballast and better on your wallet. then you will have the rest of the power already in the room for all your other stuff.If your ballast is 110 only it should still have its own breaker.I am not an expert on electricity but i have read alot about power on here and through google, and know people that are. good luck and be safe with your power.


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## basement nirvana (Mar 16, 2010)

Thank you stoner mc-b... I realized the amperage rating of the breaker box but was more concerned with the usage of the one outlet and the surge protector. I want to set this room up right and after this post and a little more research I feel I have setup my room adequately for power and safety.


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## Cpl. CornB33F (Mar 16, 2010)

Thats a lot of juice. I wouldn't do it if I were you.


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## robbie4door (Mar 16, 2010)

wouldnt the plug/receptical have to be reated 20 aps also??


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## nordowell (Mar 17, 2010)

you could prolly run 3 600s on a 20 amp breaker.


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## Drr (Mar 17, 2010)

IAm5toned said:


> a small bedroom is 15 amps. any electrician with his head not up his ass would never waste a 20 amp breaker on a bedroom circuit.
> 
> rule of thumb- 1440w of grow equipment per _dedicated #14awg cable, _15 amp breaker, max.
> 1920w of grow equipment per _dedicated #12awg cable, _20 amp breaker, max.
> ...



this guy is bang on..

the formula is Power(watts) = Volts x Amps
actually P(w)=E(v) x I(a)... 

watts, amps, volts.. are the units of measurement..

so we know our volts 120... we know our amps 20 or 15 on a lower case scenerio but we're gonna go with 20.. 

P=120x20

P=2400 watts on that circuit.. BUT

you wanna use 80% of it(some say 85%).. that's how IAm5toned arrives at the *1920 watts constant over a 20 AMP circuit*... If you wanna stay safe and have piece of mind.. BUT also that's why we invented breakers.. they are designed to trip if overused... Just hope your breaker works right.. 

Just thought i'd give a crash course on how to figure it out... and how he ended up with those numbers... it's the same thing for any volts or amps.. just punch in the numbers.. and you will get the max wattage.. then you multiply by .80 to get the 80% safe use number... 

It's a cake walk once you know the formula..

ANYWAY... those lights are 1000w X 2... if they are efeicent electronic ballasts then they probly use no more then 1100 watts each.. so 2200 watts total on a high.. (2100 in a best case scenerio) so regardless you're over your safety net BUT under your max.. you don't have much room for spikes.. which will trip the breaker and fuck your light cycle.. not worth finding out.. 

Like mentioned above the breaker will heat up over time.. it may not trip with those numbers BUT it will wear out and It may not work right over time.. WHICH is a safety concern... 

You could get away with it ...*BUT* it is not recommended and YOU'RE responsible for your actions.. 

The best thing to do here is run a second 20 amp 120 volt line.. and if your gonna do that, your better off putting in a 30amp 240 volt like mentioned by someone in this thread.. that's if you have room in the breaker... if not another 20 amp will be fine..


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## IAm5toned (Mar 17, 2010)

well the way it works is for any* equipment that is to be energized for a period greater than 6 hours shall be rated @ 120% of the maximum ampacity*... 6 hours or greater of operation is considered a continuous duty cycle, so this is done to protect the thermal element inside the breaker/fuse. not only can it cause premature tripping or nuiscance tripping, but it can also fuse/weld the breaker shut and cause a failure to trip in a short circuit condition., if you run it @ its maximum rated load with a continuous duty cycle, especially over extended periods of time. the danger is not on the first run, but maybe on the 5th.... by rating your breakers @ 80%, you prevent that.
with a 100 amp breaker, just because the numbers are simple to demonstrate-

100 amp breaker = 100% load = 100 amp

80% load = 80 amps. 

80 amps x 120% = 100 amps

you can see you the 120% works now. by rating your breakers @ 80%, your rating your equipment for 120% ampacity, as required by code 
multiplying the max amperage by .8 on a breaker, gives you the exact number of amps you can safely run. or watts. the equation works either way. i always use amps myself just because thats just easier for me, ive been doing it long enough i tend to have all the wattages memorized anyway...

so to size a breaker for a grow op- _multiply the max wattage of all connected equipment by 120%. then convert the wattage into amperage by dividing by the voltage.

heres an example: (im ust inventing the wattages, bear with me if there not dead on)

_3 600 hid lights. max input power = 660w per ballast.
2 fans 45w each
2 pumps, 75w each
timer/contacter 20w

660 x 3
45 x 2
75 x 2
+ 20
2240w
x 120%
2688w

2688w/240v= 11.2 amps @ 240v. you _always_ round up to the nearest size so for our examples sake it would be a 15 amp breaker.

to find what you can run on an existing breaker-

_multiply the amperage by the voltage by 80%_

20 amp breaker, @ 120v... how many lamps can i run on it??

20 x 120 x 80% = 1920w of lighting goodness for your baby girls.

1920w x 120% = 19.2 (always round up, remember?? so its 20 amps.)

and thats how it works. for any power equation.


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## imlegal (Mar 17, 2010)

ihave a 400w hps, a floor fan, and a small humidifier plugged to a bathroom outlet u think im maxin it out at all? thanks for any help because last thing i want to do is create a fire


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## sixstring2112 (Mar 18, 2010)

imlegal said:


> ihave a 400w hps, a floor fan, and a small humidifier plugged to a bathroom outlet u think im maxin it out at all? thanks for any help because last thing i want to do is create a fire


 you should be fine. a good hair dryer will pull 1200 - 1500 watts and your under that. nothing like takin a dump under the street lights


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## WaRpIg (Mar 18, 2010)

Dont use 14 gauage wires use 12 or 10 cuz the big number mean smaller wires ... i would use those outlet that have own breaker just in case ....so u have 2 breaker


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## JeffersonBud (Mar 18, 2010)

Its not necessarily about the watts, its more about amps. Usually 100 watts is around an amp. Most plugs in the house are rated for 15-20 amps @120 volts. There is sometimes an initial amp increase when starting a device as well. 30 amp lines are 240 volts and are usually connected to large appliances such as the oven or HVAC. If you have the option to run your ballasts off of a 240v plug, then do it! contrary to popular belief, you won't really save any money, but you will cut your devices amp usage by half. if 1 1000watt ballast runs @ 10 amps on 120v, then it can run only 5 amps on 240v. This allows more lights to run on a single breaker.
Most of your products have amp rating and this is what you want to look for.


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## WaRpIg (Mar 19, 2010)

Its not necessarily about the watts, its more about amps. Usually 100 watts is around an amp. Most plugs in the house are rated for 15-20 amps @120 volts. There is sometimes an initial amp increase when starting a device as well. 30 amp lines are 240 volts and are usually connected to large appliances such as the oven or HVAC. If you have the option to run your ballasts off of a 240v plug, then do it! contrary to popular belief, you won't really save any money, but you will cut your devices amp usage by half. if 1 1000watt ballast runs @ 10 amps on 120v, then it can run only 5 amps on 240v. This allows more lights to run on a single breaker.
Most of your products have amp rating and this is what you want to look for.


so i can run 1 1000 watts on 120v outlet with a single 20 amp breaker will be ok ?


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## JeffersonBud (Mar 19, 2010)

so i can run 1 1000 watts on 120v outlet with a single 20 amp breaker will be ok ?[/QUOTE]

Yes you can. It will most likely consume 10 amps. Just make sure that your romex wire (12 gauge) on the plug and the breaker is made for 20 amps. 20 amp plugs look like this...

http://www.frentzandsons.com/Hardware References/plugandreceptacleconfiguratio.htm

As you can see, the plugs on a 15 amp are the normal small (hot) large(neutral) and ground. The 20 amp has an extra horizontal plug space on it. Usually the plugs are rated for 15 amp even though they are using the 12 guage romex because not many people run things larger then15 amps that on a single plug. You can get away with the normal plug if you are only running 10 amps or one single light but I like to make sure everything is up to the full 20 amp spec.

Hopefully im not just rambling about things you already know


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## JeffersonBud (Mar 19, 2010)

also, you can run the regular male plugs on the 20 amp. They have the extra horizontal plug not only to distinguish it from the 15 amp, but so they can accept more devices.


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## WaRpIg (Mar 19, 2010)

the 1000 watts light power supply have 2 opt. 120 v or 240 . it had that reg plugs like house .. is it ok use that plugs or should i change it to one link u shouw me ? i only run 120 v out that power supply the 240 kinda too much for me ..


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## WaRpIg (Mar 19, 2010)

Should i change amp to 10 to be safe or is it safe with 20 amp breaker ?


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## JeffersonBud (Mar 19, 2010)

Yes, you should be fine with the plugs you have. you want to keep the 20 amp breaker. The larger amp rating on the breaker, the better. The smaller number gauge wire, the better. Are you running anything else on the circuit (all the plugs that run into the 20 amp breaker) like pumps, fans, ect?


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## IAm5toned (Mar 19, 2010)

in all seriousness, its _never_ about guessing! electricity is all about math, because math deals in _absolutes_. when dealing with electricity, dont guess. either know before you start or consult a pro. a little research can go a long way and save you thousands in the long run. a 1000w fixture does not pull 10 amps, for instance. if it did, id be worried about that ballast catching on fire.
this thread is the reason I donate my time here. call it community service for karma.

look, and listen, ok?

any HID lamp requires a ballast. the ballasts _power factor_ will tell you what wattage it pulls in addition to the lamp. thats right, a ballast also consumes electrical energy. you multiply the power factor by the lamp wattage to get the _maximum input power_. sometimes the ballast manufacturer is nice and on the nameplate rating of theballast they will put the _maximum input power._ this is what the ballast lamp combo consumes. sometimes it is in amps,and sometimes it is in watts. sometimes its not there at all, and all there is is an efficincy rating/power factor.

for examples sake, lets pretend the maximum input power of your light fixture is 1075 watts.

1075w @ 120vac = 8.96 amps
8.96 amps @ 120vac x 120% (continuous duty cycle demand factor) = 10.76 amps.
1075w @ 240vac = 4.48 amps
4.48 amps @ 240vac x 120% (continuous duty cycle demand factor) = 5.38 amps

note how the wattage never changes in relation to the voltage, but the amperage is _inversely proportionate _to the voltage. the higher the voltage, the lower the amperage. the lower the voltage, the higher the amperage.......

someoone said in a previous post a 30 amp breaker is 240v. this is horse shit. the amperage of a breaker has absolutley _nothing_ to do with the voltage of the circuit. the voltage of the circuit is determined by the availability of power from a transformer/generator. 99% of all households in the US have 120/240v single phase service. that means in order to have 240v, you must use both phases of the a/c power cycle. in plain english, that means a 240v breaker takes up 2slots in a panel. do not be fooled by a tandem breaker, also called a piggyback breaker. a tandem breaker fits 2 circuits in one slot of the of the panel, they are easily identified by there smaller size compared to other breakers. a 240v breaker will also have a bar, or _common trip_ that locks both handles together so that if one phase trips, it also trips the other.

school is now out of session.

thank you, come again


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## JeffersonBud (Mar 19, 2010)

Thanks for the clarification. I did not mean to state that all 30 amp breakers are 240v. Most of the time, household appliances are on a 30 amp double pole breaker, but as stated, a rating of amperage on a breaker does not mean its 240 volt.


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## WaRpIg (Mar 19, 2010)

I run many wires to once place like blower have own breaker and light have own breaker ...


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## robbie4door (Mar 19, 2010)

now where u plug the cord into the receptical. the plug and the cord/cord end have to be sized also???????


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## IAm5toned (Mar 20, 2010)

yes, they do. however a plug that is SPEC Grade can be run @ 100% ampacity. so a 20 amp SPEC grade plug is good for 20 amps. as long as it is terminated correctly.
dont use _anything_ but SPEC grade plugs for a grow op. they are the most expensive, but they are built for heavy duty usage, as compared to a regular .99 plug from the bargain bin isnt good for 80% of the amperage on the packaging...
cord ends need to be rated @ 120% however. that id critical. the cord end is the connection point, and is what we like to call a _point of failure_ in the trade. this means the probability of something going wrong there is pretty high, so in order to avoid problems, dont cut corners. do it right, and sleep at night... as ive told many apprentices.


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## JeffersonBud (Mar 20, 2010)

Here is a 20 amp outlet

http://www.homedepot.com/catalog/productImages/300/5a/5aed1815-a7f4-4785-ae26-945b0d245a80_300.jpg


I have these on all three of my outlets connected with 12 gauge (yellow) Romex all leading back to a single pole 20 amp breaker. Everything is rated for 20 amps clean and simple. They run all of my small 120v items in the room.


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## robbie4door (Apr 4, 2010)

thanks bud
i thought so but just wanted to stress that point of contact is the most croushal


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## stoney917 (Jul 16, 2010)

so if my math is correct. i have a 20a breaker with 14 wire ran to it. i plan on runnin a 1000w hps with 2 136w fans and 2 20w airpumps bringin me to 1312w so lets say round up 1400w total now my math tells me max load would be 1800w. is this correct? 15x120=1800 and i know you should not max it out and cannot change ne of the wiring easily.i think i remember hearing 1440 continous so im stiil below max recomendations.


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## bripay50 (Mar 7, 2015)

In a regular house... Can you put a 1000 watt and a 400 watt in the same room?


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## Aeroknow (Mar 7, 2015)

bripay50 said:


> In a regular house... Can you put a 1000 watt and a 400 watt in the same room?


Already been answered in this old ass thread on page 1 


IAm5toned said:


> a small bedroom is 15 amps. any electrician with his head not up his ass would never waste a 20 amp breaker on a bedroom circuit.
> 
> rule of thumb- 1440w of grow equipment per _dedicated #14awg cable, _15 amp breaker, max.
> 1920w of grow equipment per _dedicated #12awg cable, _20 amp breaker, max.
> ...


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## jonjon777 (Mar 7, 2015)

20 amps at 120v has a 2400 watt capacity!

Or 2000 to be safe...

Amps x volts = watts

Real simple...


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## Yodaweed (Mar 9, 2015)

basement nirvana said:


> So I was considering putting 2 1000 watt lights on the one 20 amp breaker but it is just too close for comfort, I was more concerned with the 14 gauge wire. I have decided to run another conduit line into the room from another room/circuit. When it is all finished I will have 3 separate outlets on 3 separate circuits...it's gonna be sweet. Thanks guys!


I wouldn't feel safe sleeping with all that ampage on one 20amp breaker, you are running that beyond what it is rated to do. Hire an Electrician and have him run you a 20amp 240v outlet to your grow (it only costs a couple hundred bucks). Most households have 15amp circuits so you might want to check your circuit breaker.


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## bripay50 (Mar 11, 2015)

H


Yodaweed said:


> I wouldn't feel safe sleeping with all that ampage on one 20amp breaker, you are running that beyond what it is rated to do. Hire an Electrician and have him run you a 20amp 240v outlet to your grow (it only costs a couple hundred bucks). Most households have 15amp circuits so you might want to check your circuit breaker.


How do you find out how many amps are on Ur breaker... And what's a breaker


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