240v...any advantage?

[spiralsmurf]

is there any advantage besides having a lower amp circuit? i'm going to run 4800 watts and i'm wondering if there is a reason to bring a bunch of 240v upstairs. I can pretty much run the whole thing on a 90amp circuit using the 80% electrical code rule or an 80amp without the 80% rule. i dont see the advantage except that if I have to run a new circuit i could use smaller wire with 240v.

 

[l_d_d]

A house only has so much power coming into it.

There is usually a 'main' breaker... 100-125-150-200---

If you are using 90 amps just for the grow..... your only gonna have whats left to use for EVERYTHING else.

Dont forget you will likely need your central AC and that takes some power.

See, with a 100 amp main, with your AC running.... might not be a-ok.... and would want to cut the grow amps down if possible..

Are you planning on living in the house also? This matters alot imo.

You need to figure out how big your main coming in is. After that, depending on if your living in the house or not, you should see the advantage to 240v.

 

[bartender187]

smaller wire should be incentive enough.... you could cut your amperage near half... save a ton on wire.... #4 wire costs an arm and a leg.

 

[spiralsmurf]

well it's actually in a commercial space thats currently only powering a few computers. but i see what you guys are saying, by keeping a lower amp load i can run cheaper wire. so if i run a 240v up to the room can i then split it up into 2, 120v lines? 240v has 2 hot wires, one neutral, and one ground correct? how would i go about splitting it up once i run the wire to the space? do i make a subpanel and put breakers on each 120v line?

 

[MTF-Sandman]

4800w should only need a 30a/240v line ran for it if you run them at 240v. Every time you get a size larger on the wire, the price almost doubles (unless you have a good electrical hookup), so by all means go with 240v.

There's no real advantage to running the ballasts at 120v, so don't worry about using a subpanel unless you have an assload of 120v non-lighting stuff to run.

240v can be run on 2 or 3 conductor wire. If you use 2 conductor (2 hots and a ground) then you can't split it into 120v since there would be an unbalanced load which would energize the ground leg (NOT safe). 3 conductor (2 hots, 1 common and a ground) is fine for feeding a subpanel as any unbalanced load will be sent back via the common wire.

 

[spiralsmurf]

so i can use a 10/2 cable and just go right into 8 receptacles? i'll just get 120v from other existing circuits.

so from start to finish i need to install a 30amp breaker in my existing panel and then run a 10/2 up to the growroom, then i put it into an intermatic wh40 timer and connect the output of the timer into the 8 receptacles.

 

[Guest]

Your ballasts will draw less amps on 240. Most of them come with the ratings and show the lower draw with the higher volts.

240 wiring is a larger gauge and is safer on high output.

4800 w is dick all on 100 amp service. That's four 1000 w bulbs and your other air equip.

1000 w ballast (240v)= 5 amps(roughly) x4 is only 20 amps. I've run a hell of a lot more than that on 100 Amp service with room to spare.

 

[bartender187]

so i can use a 10/2 cable and just go right into 8 receptacles? i'll just get 120v from other existing circuits.

so from start to finish i need to install a 30amp breaker in my existing panel and then run a 10/2 up to the growroom, then i put it into an intermatic wh40 timer and connect the output of the timer into the 8 receptacles.

Im not electrician, but that sounds good from here. You would want to keep it under 26amps on that circuit.

 

[badmf]

There is no real advantage in going 240 as the wire costs is minimal in the long run. Electricity is measured in kilowatts so that doesn't change your bill. The 240 is much more dangerous than 120 so factor that in as well. I have had both and found it easier to set up in 120 as most times I move 240 isn't availible all the time.
Remember to factor in the length of your run for wire size, as resistance increases with distance. I have run 1 aught and its a bit@# to bend, I use # 4 and my own grounds, copper pipe in the ground or drilled through the concrete flooring. I always advise to have a break-down for emergency "visits" from fire marshalls etc. Boxes to contain eq and plants etc. I have had this occur a few times over the years!

 

[MTF-Sandman]

so i can use a 10/2 cable and just go right into 8 receptacles? i'll just get 120v from other existing circuits.

so from start to finish i need to install a 30amp breaker in my existing panel and then run a 10/2 up to the growroom, then i put it into an intermatic wh40 timer and connect the output of the timer into the 8 receptacles.

Yeah, that's fine...personally, I'd run the 10/2 (from a 30a 2 pole breaker) to a WH40 or T104 timer in the room and have the output of the timer (14 gauge is fine for this part of the wiring) connect to 8 outlets and just plug in ballasts to them. The part about getting the 120v from exising circuits is what I'd do as well...

I even have a drawing of the wiring from those timers

 

[Guest]

For a brain tickler,the reason 14 or 12 gauge wire is fine for the load side is that it can handle the load of each individual "branch".Each lamp,or plug if receptacles are used,are individual up to the load side of the timer.The line side however has to be able to handle each individual circuit coming into the load side,thus the higher gauge wire.Makes it simpler to understand line and load.One question and sorry if I missed it.How are you planning on getting all individual load wires under single terminals?You're going to have to make a splice somewhere,and wherever that splice is you want a 10 conductor spliced to all your 14's and connected to the loadside of the timer.When you splice them all the load going into the timer will increase.Does this make sense?I'm pretty buzzed already

 

[Guest]

Can you folks see my posts?I seem to be experiencing technical difficulties

 

[spiralsmurf]

is it better to use a double pole timer to switch both hot and neutral instead of the wh40 which is single pole? also it's not ok to use standard 120v receptacles , i need to use the high voltage style right?

mtf, thanks a lot for your help in confirming my thoughts.

 

[MTF-Sandman]

The WH40 and T104 are double pole timers...you switch the 2 hot legs, not the common and a hot.

120v outlets are fine to use. Just get some quality 20a/120v commercial outlets and you'll be set. The minimum voltage rating of the outlets will usually be 600v, so there's no risk there. I do highly recommend marking the face plates with a sharpie though so you don't accidently plug in a 120v device into a 240v feed. I'm pretty sure you would never do that, but it'll make sure you don't forget.

 

[spiralsmurf]

oh, the diff between wh40 and t104 is the external master switch. i'll definitely mark the faceplates to avoid confusion...thanks again.