wire help please
#11
I plan to run a seperate line from the breaker box to the greenhouse. A few years ago my brother told me to use 14/3 for the house. I was looking at Lowe's web sight and it has "SIMpull" on almost all of the rolls of wire. What does SIMpull mean? Just curious.

My question, should a 20 AMP breaker handle grow lights, heater and fan. LOML is still searching for the heater and grow lamps she plans to be using. Do I need to concern myself with getting the amperage or wattage or both?
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#12
SIMpul is a romex wire that is a little easier to pull and does not need wire lube. As far as size of wire to pull I think #14 is a little small to do the heater, lights and a fan. Not knowing the ampere load of each it is just a guess. I would not pull anything less than #12 maybe even #10 to be safe.
The heater is the big current draw.
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#13
Lights and a fan are no big deal. Those are low very draw.

Heaters can overload a circuit pretty quickly depending on what you're doing. I used to have an electric fireplace in my old house and while it wasn't anything super fancy or special if it was on (and on the highest setting) it would frequently trip if anything more than a few lights were on at the same time. 

Look at the heater you are using (or plan to use) and plan accordingly. A 20A circuit with 12AWG is probably fine, but check the power requirements of the heater first.
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#14
(05-30-2020, 08:50 AM)Halfathumb Wrote: I plan to run a seperate line from the breaker box to the greenhouse. A few years ago my brother told me to use 14/3 for the house. I was looking at Lowe's web sight and it has "SIMpull" on almost all of the rolls of wire. What does SIMpull mean? Just curious.

My question, should a 20 AMP breaker handle grow lights, heater and fan. LOML is still searching for the heater and grow lamps she plans to be using. Do I need to concern myself with getting the amperage or wattage or both?

14 ga wire should have a breaker no larger the 15 amp,   Is this going to be direct burial ?  If so you need wire rated for it.    Roly
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#15
This is a wire gauge calculator,  you need to know the amps as well as the distance of the wire to determine the gauge.  http://wiresizecalculator.net/   If you shoot for a 5% drop, it says you need 12 gauge wire to go 100 feet for direct burial.  If the greenhouse was 200 feet away, you would need 8 gauge.   For the trouble that you will go through to bury the cable,  I would not use a shorter gauge than recommended,  especially if you will be using an electric heater, they needs lots of power.
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#16
(05-30-2020, 01:29 PM)barryvabeach Wrote: This is a wire gauge calculator,  you need to know the amps as well as the distance of the wire to determine the gauge.  http://wiresizecalculator.net/   If you shoot for a 5% drop, it says you need 12 gauge wire to go 100 feet for direct burial.  If the greenhouse was 200 feet away, you would need 8 gauge.   For the trouble that you will go through to bury the cable,  I would not use a shorter gauge than recommended,  especially if you will be using an electric heater, they needs lots of power.

^^^^^
This.  Wire gauge is dependent on BOTH the load (number of amps required for everything operating on that circut), and the total length of the wire in the circuit (not just the distance from the breaker box to the greenhouse).  My gut feel is you'll need at least a 30 amp circuit.  Problem is 12/2 or 12/3 wire is pretty big and not generally compatible with 15 amp switches.  I recommend running a separate power line from the breaker to the greenhouse, then installing a subpanel in the greenhouse.  Then you can run a dedicated line to the lights and another dedicated line to the heater - both sized appropriately for the load.  The size of the wire from the breaker to the subpanel is determined by the calculator cited above.
Still Learning,

Allan Hill
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#17
(05-30-2020, 12:08 PM)Roly Wrote: 14 ga wire should have a breaker no larger the 15 amp,   Is this going to be direct burial ?  If so you need wire rated for it.    Roly

Roly, no burial. The greenhouse is a lean to and the wire will go through the attic.
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#18
Thanks everyone. My thoughts go back to the Dirty Harry movie where he says to the effect that a good man knows his limitations. So I'm considering hiring an electrician that I've used 2 other times.
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#19
(05-31-2020, 11:14 AM)Halfathumb Wrote: Thanks everyone. My thoughts go back to the Dirty Harry movie where he says to the effect that a good man knows his limitations. So I'm considering hiring an electrician that I've used 2 other times.

Best answer.        Roly
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#20
I went and did it by myself. I didn't want to spend $700 (not that I don't blame the electricians to want to get paid fairly), but I've previously ran 2 220V additional lines in my shop. After watching several different YouTubes and one in particular I watched 3 times I was able to run 2 separate 20 Amp lines using 12/2 wire. The hardest part was climbing up in the attic and thanks to that tropical storm the temperatures had dropped to the 70's from the mid 90's.

The house hasn't burned down and I didn't electrocute myself (of course I cut off the power before hooking it up to the panel).

Thanks everyone for your useful information. Pulling 2 pieces of the 12/2 wire through the 1" conduit was like watching a fat lady put on a girdle.
Big Grin
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