How many amps do you use, what is considered safe?

[megahurts]

In getting everything set up for the coming season, I start stuff indoors to get the jump.  I was doing some research since I will be using some new equipment this year.  This year, I have a Lumigrow Pro650 and a 100w T5 fixture.  I have a Killawatt used to measure the draw and calculate costs. I'll be running these somewhere around 18h a day.  The Pro650 uses about 7.5amps on full, but can be turned down to consume as low as 3amps (obviously not as powerful at that level)   The T5 is about 1...so a total under 9 amps potential on a 120v 15a circuit.  I dont usually run fans or anything else as the Pro650 has very powerful active cooling via two 90mm fans that eliminate the need for that.  

Anyway, being on a 15a household circuit that shares a computer, I think the room light and ceiling fan that are probably not much and I know that a constant draw should only be 80% of the rated circuit, which I'll be under, would everyone consider this safe?  I think its on 14/2 wire on the circuit which would be code.  I'm sure some people around here have run multiple 400 or 600 watt hps lights on a similar circuit.  Does the typical household circuit support that safely?  That just seems like a lot of constant amps to be drawing whereas if you're in the 1000w territory, you're supposed to run it on a dedicated 240v.  I guess the fridge pulls 7a on the kitchen circuit, but I dont think thats "constant" as it runs less than an hour at a time.
 
J 

 

[salsalady]

You are correct about only using 80%.  A 15 amp circuit can handle a continuous load of 1440 watts/12 amps. 
 
The refer has a bit of in-rush when the compressor kicks on which is why it would have a 7 amp rating.  Don't underestimate the computer.  Some of those computer power supplies can be 500-750 watts. 

 

[megahurts]

so do you think less than 10amp continuous is safe?
 
I'm surprised how much powah it eats to run some LED.

 

[Weed]

14/2 seems kinda small to be running 10A continuous. Thats gonna get pretty hot.

 

[Geonerd]

Your computer and monitor certainly won't be drawing 600+ unless you've got some very high end hardware and are running an intensive program continuously.   (Coin mining, SETI, etc.)  What does the Kill-a-Watt say?
 
How far from the breaker box is your grow outlet?  On most houses, at each intermediate outlet the wire will terminate at one side of the outlet fixture and another wire will continue onward from a separate connector.
 

 
Or the wires are bridged using twist pigtails.
 

 
In either event, all those junctions are weak links.  The longer the run, the more weak points. If you have any doubts, pull the outlets and check for loose connections, burned pigtails, or any other signs of overheating or distress.
 
Or just run a robust extension cord from another circuit to your grow area.

 

[salsalady]

14/2 seems kinda small to be running 10A continuous. Thats gonna get pretty hot.

 
A properly installed 15 amp circuit using 14/2 can handle 12 amps continuous.  If you have any doubts, check the NEC.
 
 
 
 
 
 
 
 
 
In reference to the 2 very good diagrams posted by geonerd...as said, every point of connection is a weak point as is every device in line.  We always use the Pigtail system when wiring circuits.  We've had calls from people saying they have a space heater plugged into one outlet and the one next to it is glowing red.  When the outlets are wired as in the first diagram, all of the load being used by the space heater at the end of the line is passing through each and every receptacle, and cheap devices can't handle the load and have a high risk of failure.
 
Using the 2nd diagram, the wires handle the load.  Given that the connections are good, there is less risk of failure of a device or issues from drawing the max of a circuit.  Good quality devices used as designed in the first diagram have no problem, the trouble come from cheap &/or old devices.  
 
Especially in situations where there may be old, cheap devices and newer higher powered items are plugged in (be it 1500w space heaters, an 1800w hair dryer, or other high powered device), the main thing is....remember it's a 15 amp circuit, don't overload it. 

 

[Weed]

 
A properly installed 15 amp circuit using 14/2 can handle 12 amps continuous.  If you have any doubts, check the NEC.
 
 
In reference to the 2 very good diagrams posted by geonerd...as said, every point of connection is a weak point as is every device in line.

 
I dont have the code memorized. Does the NEC call for a continuous uninterrupted run of 14/2 at that current? Because besides being a weak point, every other connection is a point of resistance and those are going to add up. So is every foot of wire. And then you could factor in less or more capacity based on the number of strands in the wire. The NEC probably specifies that too.
 
At 2 amps I wasnt far off just guessing from all my years as an electrician and electronics tech. I still think it's going to get hot. Or at least pretty warm. And the resistance changes with that too.
 
Most of my electrianing was done at a shipyard with no NEC, just ABS and Coast Guard regulations. But most recently doing residential electric you wouldnt believe the amount of burned wire I have pulled out of houses that met some kind of NEC code when it was put in. It's disconcerting to see wire insulation just black and falling off from where it was wire nutted up to a foot back from that location.

 

[salsalady]

 
I dont have the code memorized. Does the NEC call for a continuous uninterrupted run of 14/2 at that current?
 
 
Because besides being a weak point, every other connection is a point of resistance and those are going to add up. So is every foot of wire. And then you could factor in less or more capacity based on the number of strands in the wire. The NEC probably specifies that too.
 
At 2 amps I wasnt far off just guessing from all my years as an electrician and electronics tech. I still think it's going to get hot. Or at least pretty warm. And the resistance changes with that too.
 
Most of my electrianing was done at a shipyard with no NEC, just ABS and Coast Guard regulations. But most recently doing residential electric you wouldnt believe the amount of burned wire I have pulled out of houses that met some kind of NEC code when it was put in. It's disconcerting to see wire insulation just black and falling off from where it was wire nutted up to a foot back from that location.

 
 
edit- if you are a person who has done( "electrianing" with no NEC) training or regulation or are performing electrical work without proper licensing,   .
 
I WOULD believe the amount of burned wire that can be in a house.  As a licensed electricians, electrical contractors, and electrical administrators, this is our business.  Both my husband and myself are electrical contractors and administrators; 2 contractor licenses, 2 administrators.   
 
Residential electrical work is one of the most regulated work areas, moreso than commercial and industrial...for a reason.  ABS or Coast Guard regs have nothing to do with residential electrical requirements. 

 

[Geonerd]

J,
 
Don't underestimate the ceiling fan and computer.
 
A realquick search indicates fans are good for 1/2A at full speed, maybe a hair more.
 
One room light.  25W CFL or 150W incandescent?  1/4 to 1+A
 
Computer and Monitor.  This might be The Straw to your wiring's camel.  What does the Killawat say? A reasonable desktop/tower will suck 1 ~ 2+A when loaded, depending on hardware and useage.  (The computer's PS is simply a maximum source rating, not any indication of actual in-use load.)  A big CRT will easily draw another 100+W, while a modern LCD flatscreen display will probably be quite a bit less.  (But don't assume anything.)
 
Add 'em up.
 
At the risk of incurring the Dread Salsa Lady's wrath, I'd suggest that your caution is entirely justified.
 
Can you verify the wire gauge?
How old is your house and wiring?  It it's fairly old, 70's era, verify the conductor material. You don't want to see any aluminum, that stuff doesn't age well. 

 

[Weed]

 
 
edit- if you are a person who has done( "electrianing" with no NEC) training or regulation or are performing electrical work without proper licensing,   .
 
I WOULD believe the amount of burned wire that can be in a house.  As a licensed electricians, electrical contractors, and electrical administrators, this is our business.  Both my husband and myself are electrical contractors and administrators; 2 contractor licenses, 2 administrators.   
 
Residential electrical work is one of the most regulated work areas, moreso than commercial and industrial...for a reason.  ABS or Coast Guard regs have nothing to do with residential electrical requirements. 

You dont need to be licensed to be an electrician to do electrical work on ships that I know of and PA doesnt have any state licensing requirements for residential or commercial electricians.
 
And really, I dont care what the government says anyway.
 
Safety I do care about. And 10A continuous will heat up 14G wire. And really there is no telling what else is going to get plugged in or added later and people tend to assume that since it was done to code it will be ok when more often than not its isnt.

 

[megahurts]

Thanks for the diagrams, thats actually something important to ponder.

The house was built in 92.  The computer, has a 450w supply and a LCD monitor, and all of that equipment draws around 1.8amps tops on the KW.  The ceiling fan is a smaller one and the lights are cfl.  I had the wall open at my panel when I wired my hot tub (6ga THHN 4 wire with GFCI cutoff) but I didnt pay enough attention to the other wires.  I guess its time to explore again, because I am starting to think that its 12/2, which would be more than acceptable.  I will confirm.  As for the circuit topology, I dont know.  This circuit is one of the longest runs from the panel.  
 
The pro650 draws from nearly nothing to the max out at about 6.25amps when fully turned up.  Its definitely not a cheaply made unit.  It cost way more than I should have spent.  Now I have to justify my expense.   I really want to run it in my kitchen where there are 20amp circuits available, but I have to keep this thing away from my curious mutts who think all dirt contains gophers and moles.  I have a feeling the new one will decide to try and carry off all my hard work as he has already destroyed several outside planters.   Maybe knock something over.  The unit does make some noise and taking up the common areas displeases the wife too.  
 
Last year, I ran a couple T5s supplemental in a window I had several trays, but it was so-so and everything was a bit stringy so I thought I'd try something powerful and see if that made better progress.  I dont like HID (because they dont seem safe) and I've already tried flouros.  Perhaps I should build a greenhouse too.  I plan to have quite a few as I've fenced and prepped a 20x50 plot in the yard and am trying to "do it right" this year.  I'm even going to try my hand at hops since I've really gotten into home brewing.  
 
I let it run all day once, and nothing got warm from breaker to all the outlets and I used the computer, and had the lights on, etc. I might just be over thinking this, but its a bad habit I have and I tend to overkill things.  I am tempted to run a dedicated line and breaker....I dont know if its truly necessary though.  I need to confirm my wire sizes first.
 
there I go thinking again.
 
J

Oh, and according the KW, my voltage out of the receptacle is 121v.  The run is approx 50ft, so nothing major.  I dont know how accurate that is (its no Fluke), but there doesnt appear to be a drop.  I should probably read it with the good multimeter.  

 

[Weed]

Thanks for the diagrams, thats actually something important to ponder.

The house was built in 92.  The computer, has a 450w supply and a LCD monitor, and all of that equipment draws around 1.8amps tops on the KW.  The ceiling fan is a smaller one and the lights are cfl.  I had the wall open at my panel when I wired my hot tub (6ga THHN 4 wire with GFCI cutoff) but I didnt pay enough attention to the other wires.  I guess its time to explore again, because I am starting to think that its 12/2, which would be more than acceptable.  I will confirm.  As for the circuit topology, I dont know.  This circuit is one of the longest runs from the panel.  
 
The pro650 draws from nearly nothing to the max out at about 6.25amps when fully turned up.  Its definitely not a cheaply made unit.  It cost way more than I should have spent.  Now I have to justify my expense.   I really want to run it in my kitchen where there are 20amp circuits available, but I have to keep this thing away from my curious mutts who think all dirt contains gophers and moles.  I have a feeling the new one will decide to try and carry off all my hard work as he has already destroyed several outside planters.   Maybe knock something over.  The unit does make some noise and taking up the common areas displeases the wife too.  
 
Last year, I ran a couple T5s supplemental in a window I had several trays, but it was so-so and everything was a bit stringy so I thought I'd try something powerful and see if that made better progress.  I dont like HID (because they dont seem safe) and I've already tried flouros.  Perhaps I should build a greenhouse too.  I plan to have quite a few as I've fenced and prepped a 20x50 plot in the yard and am trying to "do it right" this year.  I'm even going to try my hand at hops since I've really gotten into home brewing.  
 
I let it run all day once, and nothing got warm from breaker to all the outlets and I used the computer, and had the lights on, etc. I might just be over thinking this, but its a bad habit I have and I tend to overkill things.  I am tempted to run a dedicated line and breaker....I dont know if its truly necessary though.  I need to confirm my wire sizes fist.
 
there I go thinking again.
 
J

 
A T-5 is plenty enough light to not have stringy seedlings. I am thinking you were missing a breeze. Most indoor growers use some kind of fan, generally oscillating so youre not blowing in one spot too much, but enough that the plant has to slow down its jack's beanstalk like growth and put some energy into growing strong also.
 
Or it was too hot.

And those are your three main causes of leggy seedlings, light, no wind, or too hot. I think you can safely say there was enough light.

 

[megahurts]

I didnt have a fan.  Cool thing about the Lumigrow is that it has fans that move quite a bit of air.  The T5 is pretty nice, but I also wanted something with a better coverage area and its a 2G11 bulb base thats a double fixture about 14" long.  It wasnt a traditional tube that I could run for the length of the rack.  I also thought it might be hot enough to keep those seedlings interested.  It seems to take quite a bit of heat to germinate even habaneros.  Perhaps I need a heat mat.

 

[salsalady]

You dont need to be licensed to be an electrician to do electrical work on ships that I know of and PA doesnt have any state licensing requirements for residential or commercial electricians.
 
 

 
Quick note-
"you learn something new every day".  mx5 is correct that there are no licensing requirements for contractors (builders, electricians, plumbers anyone in the construction trades) in the state of PA.  Municipalities may have their own regulations.
 
-and back on topic-
The house built in '92 should have copper NM-B wire in it (aka Romex).  Take the circuit up to what you feel comfortable with keeping in mind the general quality of the electrical wiring, connectors and devices. 
 
 
cheers!