by the way, thank you for showing the math there. I always wondered how to figure that out.
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by the way, thank you for showing the math there. I always wondered how to figure that out.
Yup, basic electrical power is like this:
P=I * V where
P = Power in Watts
I = Current in Amps
V = Voltage in Volts.
You can also refer to Power in "Volt-Amps" or "VA" which technically, that's what it is, Volts * Amps = Watts. But only nerds that work in the electrical industry do this. My high school physics teacher was clear on informing us that a Watt is equal to 1 Joule per Second (J/s) and so whenever we asked him "what?" he would reply "Joule per second"
So if you know wattage and voltage, then
I = P / V. This is what I just used, 105/120 = 0.875 Amps.
P=I * V where
P = Power in Watts
I = Current in Amps
V = Voltage in Volts.
You can also refer to Power in "Volt-Amps" or "VA" which technically, that's what it is, Volts * Amps = Watts. But only nerds that work in the electrical industry do this. My high school physics teacher was clear on informing us that a Watt is equal to 1 Joule per Second (J/s) and so whenever we asked him "what?" he would reply "Joule per second"
So if you know wattage and voltage, then
I = P / V. This is what I just used, 105/120 = 0.875 Amps.
Brew12
Electrical Gru
cough cough..... power factor...... cough cough
Awesome, thank you very much! I'm sure that could come in handy down the road. I think these little plugs will be good for a temporary solution.
Brew12
Electrical Gru
Those plugs will be just fine. I wouldn't run a microwave or space heater off them, but even a large aquarium heater would be ok.
If you ever do use those calculations they are a little overly simplified for AC. I recommend adding what we will call a "fudge factor" of 0.8
P=0.8VI when solving for current. I would leave it out when solving for power. And no... trust me.. you don't want to know why!
The actual math gets tricky but the 0.8 will get keep you out of trouble if you are ever cutting it close.
LOL, your right I don't. I feel myself to be a pretty competent DIY around the house. But with the exception of changing out plugs and fixtures I don't mess with electricity. I want to have an apex one day, but I figure this will work until that's installed. At least give some control over things. Depending on how big they are, I may put more on them.
mta_morrow
Of course I have room for 1 more fish!
I am wanting to run a dedicated circuit for my new build. My issue is it’s an interior wall. But I have a plan. (Famous last words).
Outside the back of my house there is a junction box that was for a hot tub (previous owner) 220v, 30amp. I want to run sealtite from the box, fasten to the side of the house at ground level, fun it around the house to where I can drill through the wall and into a closet. Junction box in the closet. Right on the other side of the wall is where I will mount my receptacles. Since this is 220v 30a, i will split it and have 2, 15a isolates circuits. Convert to GFI. Now I have done much electric in the past 20 years, but I was a Navy and industrial electrician, and I slept at a Holiday Inn express last week.
Brew12, what do you think?
Outside the back of my house there is a junction box that was for a hot tub (previous owner) 220v, 30amp. I want to run sealtite from the box, fasten to the side of the house at ground level, fun it around the house to where I can drill through the wall and into a closet. Junction box in the closet. Right on the other side of the wall is where I will mount my receptacles. Since this is 220v 30a, i will split it and have 2, 15a isolates circuits. Convert to GFI. Now I have done much electric in the past 20 years, but I was a Navy and industrial electrician, and I slept at a Holiday Inn express last week.
Brew12, what do you think?
nerdcough cough..... power factor...... cough cough
Brew12
Electrical Gru
It isn't how I would do it and I would have to check the code book to see if it would meet code. I'm assuming your house has an attic? It is really easy to run a new feed through an attic and bring it down the wall. That way you don't have to worry about the feed being protected and fewer potential failure points.
Brew12
Electrical Gru
Yup... I'll admit it.. I am a total geek when it comes to electrical power.
Brew12
Electrical Gru
Odds are they will both trip. If they don't then it is likely that one isn't working correctly.
mta_morrow
Of course I have room for 1 more fish!
Yeah, I know. But I am not good at finding that 1 spot where you drill to get the wire where you want it.
I’m used to doing things the old Navy way.
Like if a fuse keeps blowing, you plug in a 3/8 bolt and start looking for smoke
Brew12
Electrical Gru
lolYeah, I know. But I am not good at finding that 1 spot where you drill to get the wire where you want it.
I’m used to doing things the old Navy way.
Like if a fuse keeps blowing, you plug in a 3/8 bolt and start looking for smoke
It's not that hard.
Locate where you want the new receptacles and cut out the drywall. Turn on a flashlight and stick it in the hole, pointing up.
Get measurements from both sides of that wall. Go up to the attic and use those measurements to get close to where you think you need to be. Use a paddle bit to drill a 1" hole into the 2x4 across the top of the wall. Look for the light from the flashlight. If you can't see it you didn't get between the correct studs. If you can, you are in good shape.
mta_morrow
Of course I have room for 1 more fish!
PaulPerger
Active Member
I want to add a new, smaller, circuit box with power supplied from two sources, one source will be from the current, existing box (This will be the source 99% of the time), the other will be from a receptacle outside into which I can plug a generator (only when necessary).
MAIN BOX ---sends power to---> SMALL BOX <---sends power to---GENERATOR
SMALL BOX --sends power to---> Refrigerator and Tanks
What is the best way to do this? I know I can supply power from the current box via a dual 60 Volt breaker which can act as a "switch" for power to the second box. I also know my generator has a plug for supplying power to a box via a receptacle.
In our tanks we use "one way valves" to prevent water from going backwards through our systems... Is there such a thing for an electrical system? Or is an "On/Off Switch" like a breaker in the main box sufficient for this? Basically when I am powering the Smaller box from the Larger main box, I don't want electricity traveling through the small box out to the receptacle for the Generator. Conversely, when using the Generator, I don't want power going through the small box to the large box... What is the best way to prevent these from happening?
By using "Electricity Valves" like this...
MAIN BOX ---sends power to--"ONE WAY VALVE"-> SMALL BOX <-"ONE WAY VALVE"--sends power to---Generator
SMALL BOX --sends power to---> Refrigerator and Tanks
Or by using throw switches like this...
MAIN BOX ---sends power to--"Manual Throw Switch"-> SMALL BOX <-"Manual Throw Switch"--sends power to---Generator
SMALL BOX --sends power to---> Refrigerator and Tanks
MAIN BOX ---sends power to---> SMALL BOX <---sends power to---GENERATOR
SMALL BOX --sends power to---> Refrigerator and Tanks
What is the best way to do this? I know I can supply power from the current box via a dual 60 Volt breaker which can act as a "switch" for power to the second box. I also know my generator has a plug for supplying power to a box via a receptacle.
In our tanks we use "one way valves" to prevent water from going backwards through our systems... Is there such a thing for an electrical system? Or is an "On/Off Switch" like a breaker in the main box sufficient for this? Basically when I am powering the Smaller box from the Larger main box, I don't want electricity traveling through the small box out to the receptacle for the Generator. Conversely, when using the Generator, I don't want power going through the small box to the large box... What is the best way to prevent these from happening?
By using "Electricity Valves" like this...
MAIN BOX ---sends power to--"ONE WAY VALVE"-> SMALL BOX <-"ONE WAY VALVE"--sends power to---Generator
SMALL BOX --sends power to---> Refrigerator and Tanks
Or by using throw switches like this...
MAIN BOX ---sends power to--"Manual Throw Switch"-> SMALL BOX <-"Manual Throw Switch"--sends power to---Generator
SMALL BOX --sends power to---> Refrigerator and Tanks
Brew12
Electrical Gru
What you are looking for is called a Manual Bus Transfer Switch (MBT). These allow either a generator or the utility to supply a load but do not allow both to be connected at the same time. Generac is one company that makes a nice line of them.
http://gens.generac.com/GeneracCorp...-switches/0196870SBY-A-Manual-Tswitches-1.pdf
PaulPerger
Active Member
How difficult is it to install one of these? Is it something I would need to have an electrician do? Are there usually code restrictions on these?
Brew12
Electrical Gru
It isn't hard but your local code may require it to be installed by a licensed electrician.
I installed a gfic outlet for my tank and it works perfect. The only thing is i have outlets in my living room that are hooked up to a light switch. So when i turn on the lamp it trips my tank outlet. I have lived almost a year without that lamp but it drives my wife crazy. When i opened up the switch box it didnt look like the grounds are hooked up to the switch. Could this be the issue?
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