What size cable with my transfer switch?

I have put off installing a transfer switch because the cable will need to be run the length of the house (all those joists to drill through) and the expense. Well, I found a half price 5000w switch at HD and a half price right angle drill at Ebay, so I am going to do it; but what cable size.
I have a 13a genny that satisfies all my needs. It would only require 14/2. But as long as I am doing it, I might as well install a 12/3, as the next owner might be more demanding. The cable won't be that much more, or be that much harder to use. However, the 12/3 is only good to 4800w, and the switch is 5000w. Would those lousy 200w make any real difference? Obviously they would need a 5000w genny, and even then it would only be above 4800w for very short and rare instances. I really don't want to use 10/3. It is expensive and hard to work with, and will require a significantly larger hole in the joists. Does code get involved here? Can I simply say that it is only for use with 4000w and smaller generators? I have no intention of ever going above 1600w, and expect to live here for the next 10 years at least. Thanks.
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If you're running the length of you house, unless it's a very small house the voltage drop may be excessive even though the wire won't over heat. I run #8 for mine and just pulled it through conduit rather than drilling through joists.
RB
Toller wrote:

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If you dont wire it to code you will have trouble with your insurance co if there is a problem, also on sale or if the future owner puts in a 5000w unit and has a problem #8 is best for a long run. But how long, 10 may do. Why not relocate you gen location.
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Does you unit output 220, transfer panels are wired usualy for 220. 3 wire plus ground.
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at the inlet. If the next guy wants to run 240v, he can replace the inlet. I don't see any problem with that; if one hot comes undone, it will simple disconnect half the transfer switch; it can't overload anything. Hey, that might be answer. If I use a 5-20 inlet, no one can put more than 20a into it without replacing the inlet, so 12/3 is perfectly safe. (And if he wants to use a 4000w genny, he can do so safely by just replacing the inlet. He will simply be out of luck if he wants to use a 5000w.) Since I only want to put in 13a, voltage drop is not a problem. (and it isn't much of a problem at 4000w either, though 10/3 would certainly be a better choice there.) Is this making sense?
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It makes sence to me but does the transfer panel have a problem. Arnt they prewired for 220, just a thought. So you want to use half the panel , right. You need someone that knows what to do or can be done.
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This one has 3 circuits on each leg; one pair can be connected to form a double breaker. If I simply connect both hots to the same contact, it should be fine. Or so I thinks...
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Mine is the same , and the middle 2 can be 220 and linked with a bar. Each side is 120 for Each side of the gen. but I wouldnt guess on the install talk to someone that knows.
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Ck out www.nooutage.com and call them, they sell everything and should be able to help
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I checked with the manufacturer. First they told me no, each hot had to be to a different leg of 240v.
I asked him why, since the neutral can handle the 1600w. He then agreed that for 1600w it was fine.
The problem is that someone might be dumb enough to try to run 5000w 120 through it, and the neutral would be overloaded; but with a 5-20 input, that should not be an issue.
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If you are talking about the main feed from the Generator on a 5000 watt machine...running the length of your house...you need to run 8 guage and be sure you run a ground wire too. Dont even think about 12 guage .
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As long as the cable is protected by an overcurrent device, say fuses or a circuit breaker you could use a 5000 AMP transfer switch. As long as you do not exceed the rating there is nothing that says you can not be under it. Check your voltage drops to the end recpts to make sure the 12-3 is big enough.
Did you provide for the derating of the 12-3. Your only allowed 80% draw on a 20 amp circuit.
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Which is funny. On a 100a service, #4 is acceptable. But if you're providing your own service, #12 isn't good enough for 20a.
If we follow the utility's rules, it'd be good for almost 30.
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