Experienced Electrician! Here to Answer Any and All Growroom Electrical Questions

I have a question along the same vein as gumball's. If I am using 4 120mm PC fans (2 instake, 2 exhaust) and am powering them via a 12v DC converter should they be wired in series or parallel or a combination with 2 in series on each of 2 parallel circuits? I just want to make sure I don't start a fire by trying to draw too much power from the 12v converter which I believe may be the case if I wired all 4 in parallel? But if I wire all 4 in series would I see significant drops on the CFM of the last fan or 2 in the series? Thanks!

always wire in parallel unless otherwise specified by the equipment manufacturer.
and FYI- wiring in series always increases the demand factor of the power source.

Thanks, I was under the impression that wiring in parallel increased the demand on the power source because each component in the series drew the full 12v. Where as in series the first component draws 12v and that voltage drops based on the consumption of that component so the next component in the series would get less voltage, with this continuing across all components in the series.

Got a few questions here not exactly grow room ones hopefully that will come later. need the main power first. Pulling power into my property and I think I have already made my first mistake. Heres the set up- I installed a pole with a 200 amp meter on it which the electrical company has energized via overhead service. I'm building my house with a 200 amp panel 250' from the pole. Pretty sure I blew it goin with the 200 amp service at the pole to start with probably should have requested a 400 amp. I'm at the point of trenching conduit from the pole to my house location. I was going to install 2" or 2 1/2" conduit for the run. I have no idea what size wire to pull for the 200 amp service at 250 feet. any input??????the conduit will go to the garage where I would like to have a disconnect with a few circuits, and a back up generator plug. from there I need to run a wire 60' to feed a 200 amp sub panel I installed in the house. I already bought the 200 amp switched subpanel, maybe I should install that in the garage and install a smaller sized sub in the house. any help you guys. Thanks

Don't know the specs of the fans, but you shouldn't have a prob

Surge suppressors help protect the items plugged into it from surges from the incoming power lines. they are based on MOVs (metal Oxide Varistors) These fail with *zero* warning and typically last 6 months to a year. So buy cheap ones.

The only safety built into these surge suppressors is the little circuit breaker, but they are set to 15amps, so the house breaker may trip first. (and most likely will since there probably is other things running on the same breaker circuit.)

Now on the other hand there are line conditioners, that do a LOT more. Remove transients, keep voltages in check, etc But no reason to toss on a $400 unit to protect a $100 item. They are meant more for sensitive equipment like AV where you want nice sound quality.

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Thanks man. Didnt follow it all totally, but got the jist of it. Cheers.

What would you say the safest way to power a pc fan is ? I need to power one for an extractor fan for my dry box.
I know there is quite a few ways to do it, phone charger, 12v adapter thingy seems to be the most common. But what wouls be the safest ?

Thanks again Bigbudballs. +rep m8.

oden2005 said:

Thanks, I was under the impression that wiring in parallel increased the demand on the power source because each component in the series drew the full 12v. Where as in series the first component draws 12v and that voltage drops based on the consumption of that component so the next component in the series would get less voltage, with this continuing across all components in the series.

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less voltage = more amperage = higher wattage = poor efficiency

[norcal];4209897 said:

Got a few questions here not exactly grow room ones hopefully that will come later. need the main power first. Pulling power into my property and I think I have already made my first mistake. Heres the set up- I installed a pole with a 200 amp meter on it which the electrical company has energized via overhead service. I'm building my house with a 200 amp panel 250' from the pole. Pretty sure I blew it goin with the 200 amp service at the pole to start with probably should have requested a 400 amp. I'm at the point of trenching conduit from the pole to my house location. I was going to install 2" or 2 1/2" conduit for the run. I have no idea what size wire to pull for the 200 amp service at 250 feet. any input??????the conduit will go to the garage where I would like to have a disconnect with a few circuits, and a back up generator plug. from there I need to run a wire 60' to feed a 200 amp sub panel I installed in the house. I already bought the 200 amp switched subpanel, maybe I should install that in the garage and install a smaller sized sub in the house. any help you guys. Thanks

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3/0 thwn copper.... go with the 2.5", its worth the $. pulling 3/0 through 2" 90's is no fun at all. and if you ever decide to upgrade your service, the larger pipe is already in...
the smart thing to do in your situation, since your already stuck with 200amps from the pole, would be to set whats called a 200 amp NEMA 3r main panel distribution panel on the pole.
unless your house is like 4000 sq ft with a dozen people in it theres a very high likliehood that you will never actually use the full 200 amps. however having a 200 amp panel in the house will allow you to have the proper number of circuits to fit all the breakers required for your kitchen, bedrooms, garage, etc etc. by setting a distribution panel at the pole, it will allow you to have up to a total of 6 breakers in it.... you following me yet?
set the 200 amp distribution panel on the pole. feed your house panel from it with a 200 amp breaker and 3/0.
now here's where it gets ccol, and you get bailed out, albeit the cost is more... but it is a fix, a legal fix, and a really good one at that.
so now youve got a 200 amp panel on the pole... with 5 slots left.... use the 5 remaining slots left in the distribution panel to feed a seperate panel strictly for the grow.
not the cheapest option, but prolly the best option. as long as you dont exceed 120 amps on your grow equipment, youll be fine

IAm5toned said:

less voltage = more amperage = higher wattage = poor efficiency

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So does that mean if I use a lower voltage it will draw more amps , or need more?, giving me a higher wattage but lower efficiency?

So like I said, stay as close to the required volts/amps as recommended on the device and you'll get peak efficiency???

amperage and voltage are inversely proportionate... the higher the voltage, the lower the amperage.

voltage is the force 'pushing' on the electrons flowing through a circuit. the higher the voltage, the more force.
amperage is a unit of measurement that dictates the amount of electrons physically moving through a conductor. 1 amp is actually a numeric expression of a finite number of electrons. please do not ask me how many electrons are in one amp... google it.
wattage is used to express the amount of work being done.. i.e, the exact amount of energy consumed or required by a device.


so voltage is inversely proportionate to amperage. wattage does not change, unless the circuit path affects the wattage.... voltage drop greatly affects wattage. buy restricting the amount of it (the wattage)available. the more voltage drop, higher amperage is required to maintain the power consumption. if your voltage drop causes the power consumption to exceed the ampacity rating of the device your are running, the device will begin to overheat and burn...
ex-
1000w @ 120v = 12 amps
1000w @ 12v = 120 amps

so if you series connected 10 1000w lamps together... the last lamp would be pulling 120 amps... make sense?

and im sorry if thats a little confusing... but you should see how confusing the 127 page book i have that explains pretty much the same thing i said, lol... its alot to grasp

Its ok, your too smart on the subjecT for us to fully comprehend the details, but I get the jist of it.

That's a good thing by the way. I get it all the time when I talk to people about servers and networks. I know the subject well so I unintentionally go over the head of who I am talking to. Thanks Mr 5toned! +rep to u when I get home.

Hey there. Noob to this site and had a question on wiring two fans to a single thermostat.

I have a 6' x 6' x 12' greenhouse and will be installing two box fans from Walmart. One for intake and one for exhaust. I haven't picked up the fans yet so I do not know the voltage/current. My plan is to use a single thermostat that turns both fans on at the same time. Here is the thermostat's specs that I am looking at.

RATINGS: 16 full load amps @ 120 Volts AC.

30 deg. F to 110 Deg.F temp. range with + or - 2 Degrees accuracy.

2.5 degree differential.

Would is be possible to wire both fans into a junction box and then wire the thermostat to the box? (or any other advice on a better way)

Thanks for any info!

IAm5toned said:

and im sorry if thats a little confusing... but you should see how confusing the 127 page book i have that explains pretty much the same thing i said, lol... its alot to grasp

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I understand it every time I've seen you explain it. Then I trip myself up smoking and planning You are the Man for all things to do with electrons Thanks again.
Daniels
(almost got my LED's set up for the trial)

IAm5toned said:

3/0 thwn copper.... go with the 2.5", its worth the $. pulling 3/0 through 2" 90's is no fun at all. and if you ever decide to upgrade your service, the larger pipe is already in...
the smart thing to do in your situation, since your already stuck with 200amps from the pole, would be to set whats called a 200 amp NEMA 3r main panel distribution panel on the pole.

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Why pull copper when it's so costly? Go with 4/0 AL triplex and if you are looking to save even more money you don't need conduit except when coming in/out of the building, but I would put conduit under any concrete or driveway depending on how long you are going to live there. If you did go with conduit depending on your bends that you need I would always run 3" and use long sweep 90's. It all depends where you buys this at I guess. I could get this setup way cheaper then using copper. Nobody I have ever seen uses copper feeders for residential housing.

IAm5toned said:

less voltage = more amperage = higher wattage = poor efficiency

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Wait. watts = volt x amps. if resistance (which is a static here) is the same, watts should be the same. Now there other varibles in play that effect efficiency.

Sounds good. but with the specs, sounds like it can be, say, off at 70, and on at 74.5. Far from bad and the 2.5degree diff keeps it from cycling 15 times a minute.

use a reg thermometer to set it for 'real'.

limboavionic said:

Hey there. Noob to this site and had a question on wiring two fans to a single thermostat.

I have a 6' x 6' x 12' greenhouse and will be installing two box fans from Walmart. One for intake and one for exhaust. I haven't picked up the fans yet so I do not know the voltage/current. My plan is to use a single thermostat that turns both fans on at the same time. Here is the thermostat's specs that I am looking at.

RATINGS: 16 full load amps @ 120 Volts AC.

30 deg. F to 110 Deg.F temp. range with + or - 2 Degrees accuracy.

2.5 degree differential.

Would is be possible to wire both fans into a junction box and then wire the thermostat to the box? (or any other advice on a better way)

Thanks for any info!

Click to expand...

mochadog70 said:

Why pull copper when it's so costly? Go with 4/0 AL triplex and if you are looking to save even more money you don't need conduit except when coming in/out of the building, but I would put conduit under any concrete or driveway depending on how long you are going to live there. If you did go with conduit depending on your bends that you need I would always run 3" and use long sweep 90's. It all depends where you buys this at I guess. I could get this setup way cheaper then using copper. Nobody I have ever seen uses copper feeders for residential housing.

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never pull aluminum wire underground... it doesnt last 2 decades.

BigBudBalls said:

Wait. watts = volt x amps. if resistance (which is a static here) is the same, watts should be the same. Now there other varibles in play that effect efficiency.

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in that example the increase in wattage came from the voltage drop due to a series connected circuit....

Thanks for the advice on my project. I was able to figure out how to wire my house myself, but when it comes to panel and subpanel feeds its hard to find info. Definatley will go with the 2.5" conduit to make life easier. So i'm reading wat you wrote about the NEMA 3r at the pole. What is that exactly? I installed my 200 amp panel with the meter socket at my customer supplied pole which is energized. It has quite a few breaker spots left. If I ran a separate feed for a grow would that mean an additional conduit and copper wire. I'd like to split for a grow at the garage and not run two conduits. Am I missin something good here?

Is there such thing as a 30 amp for a 110v breaker?