Funfunfun

Like many of us in the Northern Hemisphere this time of year, my grow room is getting too hot and I need to add an air conditioner. I currently have two options to power it. There is a 15 amp circuit rarely used for anything else with an outlet near enough to the room that an extension cord could be run from it to the AC. There is also a 20 amp circuit with only one outlet, which is outside on the electricity pole, but right outside the grow room and an extension cord could be run from it through the crawlspace and floor into the grow room. I know it's not advisable to run an AC with an extension cord but it would be a very heavy duty indoor/outdoor type. I don't know how to add a circuit myself or wire the one outside directly inside and it would be lots of time and work to shut down and hide everything so someone else could come in and wire a circuit for me. I was thinking if I did use the outside outlet, I could wrap plastic and tape and stuff or something around it to make sure it didn't get wet? Any possible way it would be OK? I figure the AC would be 1500W and too much for the 15 amp circuit to run safely.

tripps

Wow, that's gotta be some kind of record!

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g13laze

I think it is.

Wtf?

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ltsystems

it is best to run high wattage / high inductive load devices I.E. pumps, air compressors, ac units, transformers on there own circuit.
try to avoid extension cords. there are easily damaged. if you plug in a ac motor to a extension cord that is to long or the wire gage is too small you may have a large voltage drop between the outlet and the device. this can damage the motor windings do to the increase in the current needed by the motor to run at the reduced voltage.

ltsystems

this may help.

Extension cord notes:

1. Wire has resistance. The resistance per foot depends on the construction of the wire (number and size of strands). The maximum amount of current that can be provided by an extension cord depends on the type of insulation used in the construction of the cord, and the number of conductors in the cord.
2. Because current is passed through the resistance in the wire, voltage across the wire drops. This voltage drop should be kept to under 2%. If the voltage drop is greater than 2%, efficiency of the appliance is severely decreased (and can also result in damage to some equipment). Larger wire size, or decreased current requirements can reduce the voltage drop.

Lets forget the details for a moment to examine the table below:

Max length of wire in feet for 120 volt, 2% max voltage drop allowed Current and power for 120 VOLT Max extension cord length for given wire size Amps Watts #14 #12 #10 #8 #6 1 120 450 700 1100 1800 2800 5 600 90 140 225 360 575 10 1200 45 70 115 180 285 15 1800 30 47 75 120 190 20 2400 NO! 36 57 90 140 (The data above might look messed up if you are not using Netscape)


Max length of wire in feet for 240 volt, 2% max voltage drop allowed Current and power for 240 VOLT Max extension cord length for given wire size Amps Watts #14 #12 #10 #8 #6 1 240 900 1400 2200 3600 5600 5 1200 180 285 455 720 1020 10 2400 90 140 225 360 525 15 3600 60 95 150 240 350 20 4800 NO! 70 110 180 265 (The data above might look messed up if you are not using Netscape)
From the above tables, a few things should be pointed out:
Voltage drop can be calculated using Ohm's Law which is given by... Voltage drop = Current (amps) x Resistance (Ohms).
Let's take an example where you might want to use a 200 foot, 14 gage extension cord to run a 1000 Watt flood lamp:

• Current = 1000 watts / 120 volts = 8.33 Amps
• Resistance of #14 wire = 0.00258 ohms/foot x 200 feet = 0.516 ohms
• Voltage drop = 8.33 amps x 0.516 ohms = 4.29 volts
• Percent drop = 4.29 volts / 120 volts = 3.6 %

A 3.6% voltage drop is above our recommended 2% max voltage drop given in the table above (for 120 volt). Either the wattage of the lamp must be reduced, or a larger size wire (12 gage) must be used. The larger size wire has less resistance per foot, so the voltage drop will be less.

see the tables heer

Everything you ever wanted to know aboutemergency power, lights and generators! (Part 2)

boss429

Is there any way you can run smaller appliances from the 15amp through an extension cord? water, air pumps, fans, co2, ect. all draw a small ammount of amps and then maybe you can plug your ballast and AC unit into the outlets that are actually in your room and not have to worry about overloading an extension chord.

ltsystems

yes, you can use a extension cord plugged in to a "power strip" to run a few small appliances, BUT it must still comply with the info. i posted above.

be sure that the outlet that the "extension cord" you plug in is not on the same circuit as your outlets that supply your ballast and AC unit.

tripps

I use only 12 ga extension cords for everything, always the shortest run possible, often overkill, but better safe than sorry. Sometimes you can only find the shorties, ie 6' or 10' in 14ga or 16 ga, okay for fans and stuff, but I wouldn't use them for lighting.

__________________
I may very well be laughing at you, not with you.

"The greatest obstacle to discovery is not ignorance-it is the illusion of knowledge"-Daniel Boorstin

"Tell me and I forget, show me and I remember, involve me and I understand." John Gay

Hi! It's me... the girl from the bus...Remember? The last tour? Well...Information is not knowledge. Knowledge is not wisdom. Wisdom is not truth. Truth is not beauty. Beauty is not love. Love is not music. Music is THE BEST...Wisdom is the domain of the Wis (which is extinct).

"If I cannot laugh in Heaven, I do not wish to go there."- Martin Luther

First journal Soil
Second journal Hempy
Third Journal Ebb and Flow

Weedhound

Question: I'm running a 400w mh ballast and 170 cfm inline fine off a power strip and extension cord 25 feet long. The extension cord is rated for 1875 watts....is this ok for what I'm doing or am I causing some damage I don't know about?
Thanks for any info guys.

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ltsystems

it will work fine.

rout the cord so it can not pulled, crushed, covered up or exposed to liquids.