Wire sizing information you might need
I needed to run some wire 420 feet to my shack on the river.
Found this site which was a big help.
You might want to add this to your favorites.
http://www.powerstream.com/Wire_Size.htm
I needed to run some wire 420 feet to my shack on the river.
Found this site which was a big help.
You might want to add this to your favorites.
http://www.powerstream.com/Wire_Size.htm
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Replies
Arrowshooter and ALL,
In case you weren't aware, the table you referenced is not based on the National Electrical Code (US) abbreviated NEC. The most recent 'version' is (I believe) 2005.
The table you reference / cite indicates #12 wire can carry 41 Amps for chassis wiring and 9.3 for power transmission.
The NEC says #12 CU (copper) wire is rated to safely carry 20 Amps if no more than three (3) in a bundle or conduit. http://www.okonite.com/engineering/nec-ampacity-tables.html
I hope this helps with your decision making regarding supplying power to your shack 420 feet from ___? The variables you need to consider are; maximum desired (needed) current, wire size, and distance/length of the circuit. Thus if the distance is fixed at 420' and you only plan to use one 100 watt lightbulb the needed wire size would be minimal. If you want to use an electric hot plate / small electric heater, the wire size would have to be much LARGER.
Neither you, any chart, nor any electrician can determine what size wire you need until the maximum needed / anticipated load is known.
Hope this helped! Be well and be SAFE!
Mrs. Robin A-W
"The NEC says #12 CU (copper) wire is rated to safely carry 20 Amps if no more than three (3) in a bundle or conduit. http://www.okonite.com/engineering/nec-ampacity-tables.html"That isn't exactly correct either.You need to use table 310-16 for the basic numbers and then the different sections for derating.http://www.lappusa.com/14030.16description.htm#12 has an ampacity of 25 (and 30 in some cases) which you can use for purposes derating. But you are limited to 20 amp breaker (unless it is a motor circuit).
Bill,
Yep, but <!----> unless I misread the NEC, the rating, 25 Amps, you cite is for a single conductor in free air at 75º F (I think that was the temp referenced).
I agree there are exceptions / limitations etc. My primary objective was to point out / explain that the 9.3 Amp was way beyond conservative.
Over current protection (breakers, used to be fuses) is, appropriately, more conservative (focused on safety) than ampacity of wire sizes.
Be well and be SAFE! <!---->
Actually I pasted the wrong link.Here is one with the full table.http://www.lappusa.com/14030.16description.htm25 amps is good for 60 c wire also.