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WY_mark
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# Posted: 4 Apr 2013 11:21am
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it's time for insulation and before we do that I'd like to get some wires in the walls. I can literally put my main AC panel anywhere in the house (we're entirely off grid). can someone give me a good idea of ideal max distances from panel to battery to inverter to breaker box? we have a 20x30 building so I should be able to keep each of those distances well under 50 feet, is there a particular run that benefits from being shorter? I know that you can go up in wire size to compensate for distance, but are there rules of thumb (e.g. where posible keep the bateries 20 feet from the breaker box)?
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CabinBuilder
Admin
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# Posted: 4 Apr 2013 11:47am
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Check out this wiring cabin post. It also has a link to the Voltage Drop Calculator.
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GomerPile
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# Posted: 4 Apr 2013 11:48am - Edited by: GomerPile
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The battery to inverter connections should be close as possible using the largest gauge wire possible.
Assuming you are using AC power in the cabin none of those wire runs matter (just follow NEC). If you are using 12V DC in the house then use 10 AWG wire no longer than 20 feet (40ft total wire) and your voltage loss at 15 amps will be about 0.6v which should not hurt anything.
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cman47c
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# Posted: 4 Apr 2013 11:51am
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The critical distance is the DC voltage distance for the solar cell to battery and battery to inverter. These should be kept short. The solar panel to battery is usually lower current but needs to be short to prevent voltage drop. The battery to inverter is large current draw so this should be very short and use very large gage wire. The inverter to breaker box at 120 VAC is not critical for length unless it is extremely long.
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Alaskaman
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# Posted: 5 Apr 2013 03:23pm - Edited by: Alaskaman
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If you are in a log cabin you have to use MC (Metal Clad) wire to meet code.
This is for the circuits running out from your distribution panel.
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GomerPile
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# Posted: 5 Apr 2013 04:42pm - Edited by: GomerPile
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Can you site an NEC code for this? I don't think its true 100% of the time. Sure there are instances where MC is required but they are not specific to log construction. Most log homes I have seen use romex thru holes drilled in logs....sometimes good builders line the holes with PVC conduit.
Quoting: Alaskaman If you are in a log cabin you have to use MC (Metal Clad) wire to meet code. This is for the circuits running out from your distribution panel.
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ICC
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# Posted: 5 Apr 2013 05:01pm
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I believe it depends on the wiring method. If the wiring is recessed somehow back into the logs, a minimum of 1 1/4 inches behind the surface then romex should be okay. If the wiring is surface or less than 1 1/4" behind the wall surface then metallic cable or conduit or other surface raceways are needed. And the electrical inspector usually has last word unless you can show he's wrong. ( I could have the measurement wrong as that is just what my memory retrieved.
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Alaskaman
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# Posted: 5 Apr 2013 05:12pm
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I got the information from a journeyman electricain friend of mine. He saw one of my branch ciruits and said, "You realize if you ever want to sell this place code requires MC right"? I also confirmed it with an electrical engineer I work with. I'm neither, just passing along what I have been told. It may be Alaska specific since there are a lot of cabins up here and lots of them burn to the ground every winter.
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bldginsp
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# Posted: 6 Apr 2013 05:16pm
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The basic principle is just that the wiring is protected against impact damage or nail puncture.
The 1-1/4" is to avoid nail puncture. In studs in a wall if the romex is less than 1-1/4" from the edge of the stud then you need to put nail plates on the stud edge so the sheetrock nails or screws won't puncture the wire insulation.
MC cable is just one surface mount wiring method allowed by the NEC- there are lots of others. The electrician who said 'If you want to sell this place the wire needs to be in MC' probably meant that it needs to be in MC at least, since it is a less expensive wiring method that is approved for surface use. You could run plain metal conduit, pvc conduit, decorative conduit/wireway which is meant for the purpose, etc. Lots of choices.
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