You are watching: Wire size for 125 amp service panel
If her local electrical inspectors permit the usage of NEC table 310.15(B)(6) because that residential below panel feeders, climate #2 copper is acceptable for 125A. (residential key feeder rule)If your fill calculations come in at much less than 115A, climate #2 copper may be safeguarded with a 125A breaker. (round up rule)Otherwise you will have to use #1 copper for her conductors.Voltage drop must not be a significant issue in ~ this distance.-Jon
Since I have actually not however bought the wire, then i may also get #1. Phoenix supplies the NEC so it will certainly be ok. But existing conduit is in the attic and also is RNC (pvc Sched 40) 1.25". Watch a small tight because that #1..... Fill chart states I am ok..... What size ground would certainly I climate use??? #4 ???? and also can I usage insulated wire for soil THHN..... I have some already... Thanks
Since you room using a 100 amp breaker to feeding this dashboard you have the right to most most likely use 310.15(B)(6) i beg your pardon will permit #4cu for the hots and also neutral. A #8 soil is all the is needed.Just dual check v your neighborhood code office to see if this graph is provided in your area. It is in mine.
I plan to use at the very least #2. I might want to increase its consumption later, you never ever know. I recognize I cant walk behyond the 125A, therefore if I want to setup for later and still usage a 100A breaker for now, must I go #1 or will certainly #2 occupational ok???? If that is in the NEC then my inspector said he will certainly accept it.... Ground size for #2 is #6?? What ground because that #1 ??????/ many thanks again
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That would be a huge whoops on my part.I saw the 125A panel number however not the 100A breaker number. My above assessment thus transforms to:If your local electric inspectors permit the usage of NEC table 310.15(B)(6) because that residential sub panel feeders, climate #4 copper is acceptable for 100A. (residential main feeder rule)If your load calculations come in at less than 85A, climate #4 copper might be defended with a 90A breaker. (round up rule) (This is if the above statement doesn"t apply.)Otherwise friend will must use #3 copper for your conductors protected by the 100A breaker.Voltage drop have to not it is in a far-reaching issue in ~ this distance.The minimum size for the equipment grounding conductor would be #8 copper. It have the right to be _green_ insulated THHN, bare, or _larger_ that #6 copper and significant with environment-friendly tape in ~ the ends. -Jon