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Small Cabin Forum / Cabin Construction / Electrical wire and freezing conditions
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DungeonX
Member
# Posted: 10 Jan 2013 13:25
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What type of wire should I install in my cabin. which will experience freezing conditions and only be heated when in use. My cabin is in northern ontario typical temp can get down to -30 or more. I have been told to run 10/2 from the generator to the cabin but can i use 14/2 inside to my plugs and lights?
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Rossman
# Posted: 10 Jan 2013 13:44
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I don't believe wiring is affected by the cold?

Wire gauge/sizing is based on how much power it will carry over a given distance. Cold weather should have no effect.

Anonymous
# Posted: 10 Jan 2013 14:03
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Rossman is correct although I would probably run a little heavier gauge from genny to cabin if possible and affordible

MtnDon
Member
# Posted: 10 Jan 2013 14:17
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10 AWG wire is meant for maximum 30 amp current. If that is the generators maximum output and if the wire length from generator to cabin connection is 50 feet or less, 10 AWG will be fine. That is using 3% as the maximum voltage drop. Power companies usually calculate on a max drop of 5%, but I am more conservative. And no cold is not an issue.

DungeonX
Member
# Posted: 10 Jan 2013 14:38
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my generator has a 2 - 15amp circuits and 1- 20 amp circuit, im not sure whether they can both run at the same time? and the max output is 3000Watts

bobbotron
Member
# Posted: 10 Jan 2013 14:52
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Quoting: DungeonX
my generator has a 2 - 15amp circuits and 1- 20 amp circuit, im not sure whether they can both run at the same time? and the max output is 3000Watts


I believe they can't, it's either/or. You either run the 2 15 amp plugs or the 20 amp circuit. 3000 watts is about 19 amps (ish?) Who knows, it might work plugging into all of the ports, but imagine the generator wouldn't be too happy about it.

Did you buy one of the 3000 watt champion generators? I bought one of those from Canadian Tire - they're pretty good for the money...

MtnDon
Member
# Posted: 10 Jan 2013 14:55
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3000 watts = 25 amps at 120 VAC.

With 2 x15 and 1 x20 how do you intend to connect to the cabin? Do all the receptacles go dark when the built in breaker trips? (there should be a breaker or two) And what devices do you want to run in the cabin? What loads?

Rob_O
# Posted: 10 Jan 2013 16:58
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Quoting: bobbotron
3000 watts is about 19 amps (ish?)


Quoting: MtnDon
3000 watts = 25 amps at 120 VAC.


I think you're both right. Don is mathematically correct but the generator probably has a max continuous output of 20 amps or less

Quoting: MtnDon
what devices do you want to run in the cabin? What loads?


This is the important question. Give us a quick rundown of what you need to run and we can tell you what size wire you need to run it

MtnDon
Member
# Posted: 10 Jan 2013 19:30
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Yes, Rob... I never gave any thought to whether or not the 3000 figure was peak or continual running power. Some ratings are given one eay and others the other.

DungeonX
Member
# Posted: 11 Jan 2013 08:30
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i think the generator says 2850 watts continuous 3000 is the peak. I dont plan on anything too demanding, a tv a dvd, cell phone chargers and a booster, and of course 6- 8 lightbulbs.

MtnDon
Member
# Posted: 11 Jan 2013 10:12
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This is an opinion. If those are the loads it may get "old" real fast running a generator all the time some electricity is needed, especially if the generator is one of those noisy beasts that runs at 3600 rpm's all the time. With small loads like that I believe everybody would be happier if you had 2 or 4 golf cart batteries, weries - parallel connected for 12 volts DC. Then a small inverter to supply AC. Charge that as necessary from the generator with a good 3 stage stand alone battery charger. Add a small PV panel to maintain the batteries while the place is vacant. Add more PV later if you can't install more now.

Think about it. Generators are noisy, smelly, require fuel and maintenance, etc. People use them a lot; I do not like them for regular use. I've done that and got tired of it. Just FYI and just an opinion.

DungeonX
Member
# Posted: 11 Jan 2013 10:47
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I do agree with your thoughts mtndon. I just want to be prepared for later if i do go to a solar setup I want to not have to re open walls to run wire. and for now since i am still in the construction phase I will need to run some power tools. But thank you for all your insight and direction it is appreciated.

TomChum
Member
# Posted: 11 Jan 2013 11:38 - Edited by: TomChum
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Since the cabin is empty for long period in freezing conditions, consider protection of all your wiring from rodents who might think of the wire casing as food or at least chewing gum. That's the only freezing temp problem I can think of.

If you're running wires now, why don't you run 2 sets of wire to some of the boxes? Use romex 14/2 and, maybe 14ga speakerwire for your 12vDC. That gives you the option to add some 12vDC LEDs later. 14ga is huge for LED lighting but I'd use a big wire for the durability and for small losses, but fuse it at the panel with a tiny 2A fuse. For a little cabin it won't be much work to run a speakerwire to all boxes, even light switches. Which makes the complication a little simpler if EVERY circuit has both 12vDC and 120v options. Of course you CAN use the romex for 12v, but if there's speakerwire in there you know its for 12vDC. Don't expect someone else to understand it, or to pass an inspection. You will be the King of that cabin's panel and wiring.

At my cabin it's simpler though, all lighting is 12vDC and just two outlets (one inside & one outside) with 120vAC.

If you use 120vAC Compact Fluorescent lights, which use 1/5th the power of incandescent, your batteries will light the cabin about 4x as long. Use of CFL incurs additional conversion losses from your inverter changing 12vDC to 120vAC. And CFL don't like to startup at low temps, and won't last long if they have to start up in the cold. I don't use CFL or any 120v lighting.

If you use 12vDC LEDs your lighting will use 1/10th the power of incandescent, so can run 10x as long, and they last almost forever. Choose the "warm white" LEDS, then the lighting looks the same as incandescent, very nice. If you choose the LEDs with maximum light output you can get more light but it will be harsh light.

I use 4 golf cart batteries with solar panels. In the winter if it's cloudy I have to run the generator for a couple hours a day. Many people understand generators better than they understand battery maintenance so an expensive set of batteries might not be a wise purchase, until you're committed to learn how to maintain batteries. If you spend $300 on batteries you WILL be inclined to learn, and it's not so hard. But if you let them go dead the water will freeze, and they'll crack open and spill all the acid out! You will have to put in a voltmeter, and watch the voltage never drops below 12.4 (if you want them to last 5 years). It's not difficult, you can get a voltmeter for $4.99 on the internet.

Some don't mind generator noise, maybe they're watching TV all day anyway. Not me I prefer the sound of silence and also the thought of sunlight pushing electrons into my batteries for free! I like the silence, I can hear if a truck is driving by on the road, or friends coming to visit. With the generator running I don't enjoy my woods retreat. I run a 50+ Amp charger to get the charging done ASAP!

Rob_O
# Posted: 11 Jan 2013 19:31
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Quoting: DungeonX
I dont plan on anything too demanding, a tv a dvd, cell phone chargers and a booster, and of course 6- 8 lightbulbs.


For those loads 14 gauge wire will be adequate. You can use a 2 space/4 circuit load center (often sold as an AC disconnect) with a pair of twinned breakers to provide 4 circuits to the cabin (or 3 circuits with a main disconnect).

10 gauge will be right for the line from the generator to the cabin. Is the 20A outlet on your generator a twist-lock?

ljohnsaw
Member
# Posted: 12 Jan 2013 14:16
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Quoting: Rossman
I don't believe wiring is affected by the cold?


Not entirely true...

As you approach absolute zero (-473C, I believe), the resistance in the wire approaches zero and the electrons fly freely. Now it doesn't get quite that cold in Canada, but pretty close!

I built a barn 20+ years ago and had access to lots of rolls of wire (single color stuff) so I decided to run EMT (conduit) for all my circuits to protect from rodents and never regretted it. When I build my cabin, conduit all the way (and not PVC!).

I plan to use 12g wire for my low voltage setup (off grid). I figure at some point in the near future, solar and batteries will advance enough that I may switch to 120v to gain some modern conveniences and I won't have to re-wire.

bldginsp
# Posted: 13 Jan 2013 18:31
Reply 


I think this has pretty much been said above, but I'll just summarize a bit-

You can run all the circuits you want in the building, what matters is how much amperage you pull through each. Each circuit is limited by the wire size and breaker, and the total capacity of all amperage pulled through all circuits is a function of your source power capability.

Just cause a circuit is a 15 amp with 14 gauge wire doesn't mean it's pulling 15 amps all the time. Maybe you just have one light bulb on it. If you try to pull more than 15 amps through that circuit the breaker will trip, but your loads should be distributed through numerous circuits so no one circuit ever gets overloaded.

I plan to put in a 100 amp subpanel with 8 or 10 circuits in my 300 sq ft cabin, even though I don't have the elec utility, and all I may ever have is a few batteries charged with solar. The point made above that it's easier to install the wiring while the walls are open is the operating principle.

Cold won't damage your wiring, but water will. Seal off all your outside boxes, protect them from rain with little roofs, and use wire with water rated insulation in outside conduit under or above ground. Water condenses in conduit outside, it will get wet. THWN is one typical insulation designation for water resistant insulation. Make sure you have a ground path back to your circuit breakers. If you don't know what that means, please find out. The breakers cannot clear ground faults if the ground path doesn't exist or is broken by bad connections.

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