125 AMP Load Center Sub Panel Wiring Size?

Actually you say you are going to use anti oxidation compound which leads me to think your using aluminum wire with that being said section 310-15(B)(6) of the nec ( national electric code) states that for 100 amp the correct wire size is # 2.but after using this formula for voltage drop R= K x L /Cm you will find that the actual wire size is 1/0 al. R = resistance of wire K = ohms per mil foot L=length of wire (300 feet 2 phases and neutral) and cm = circular mils or size of wire. Also make sure to scuff up surface of wire to scratch off flash corrosion so no-lox or penetrox will work.(anti oxidation compound. ALSO IF YOU CHECK YOU WILL FIND THAT THE EASY TO READ TABLE STATED ABOVE 310-15B6 TABLE FOR RESIDENTIAL 120/240 3 WIRE SINGLE PHASE SERVICES/OR FEEDERS HAS THE SAME AMPACITIES STATED ANY WERE IN CHAPTER 310-15 hence the 310-15 PREFIX AND THE RATINGS LISTED IN 310-15 B-6 ARE NOT JUST FOR FEEDERS BUT ALSO FOR ANY SERVICE OR SUB PANEL. WHAT DO YOU CALL THE WIRES FEEDING A SUB-PANEL ??? A FEEDER...

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125 AMP Load Center Sub Panel Wiring Size?

I am installing a 125 AMP Load Center in my house to service an addition. I will be installing a 100AMP breaker in my main panel. I understand I could use a 125 Amp breaker but I do not need the additional amperage. I assume I need to run 4 wires (2 Hot, 1 Neutral and 1 Ground). The run is no...

I have some 4/0 al wire. I have a 200 amp panel and want a 125 amp sub panel using the 4/0 seeing as i already have it being it is left over for 200' run to breaker/meter at road. Do they make pin adapters to facilitate this?

Max breaker = 60 Amp double pole.for this line.It seems to me that the most popular panels on the market now are 100 Amp. I don't think they are much more expensive than a 60 Amp. If you have the cable, than use it of course. You may use this 6-3 cable to feed it as long as the panel is protected with a 60Amp. main. The advantage of using a 100Amp panel is, you can put more dedicated ccts in the 100Amp panel. Remember , not all ccts are fully loaded. So this way you have more diversity. Hope this helps.

You never use a bonding screw for a sub-panel. I assume you are using table 310.15b6? If so, you can't use this for sub-panels. You need to use 310.15, since the load is NOT carrying teh entire load of the dwelling, you can't use 310.15b5. You will need to run, 1/0 aluminum or #2 copper(as long as load is not more than 95 amps). Alot of electricians don't know when to use either chart. I hope they clear it up in the 2010 code, b/c it is a dumb code, but a code nonetheless.

Yes, you are right. 2-2-2-4 is the right size.

I'm not sure what you are asking with your grounding question so let me just tell you what to do with it.

in your main panel, the bare and neutral go to the ground/neutral bar. It is probably the same bare there. If it's separate, then you can separate them. Either way is fine.

In your sub panel, you are right, no green bonding screw. But you now need two separate bars. A neutral bar and a ground bar. I like to put a ground bar on each side for convenience. But it is not required.

Good luck. You sound like you know what you are doing.

you have the correct size as far as aluminum goes but the wiring is 2 hot 1 neutral and 1 ground. Yes you will have to use the bonding screw even though it is a sub fed from a separate breaker because it is (i assume) out of sight of the feeder and the panel you are putting in has a spot for both the neutral and the ground wires.

Mike is right, after looking a little deeper into code I saw the reference, Jeez you would think after 14 years of doing this you could see their misdirection. Sorry

You have done your homework.

Yes #2 Al is the right wire size.

Yes Connect that ground wire to the grounding bar.

(You can also tie it to the grounding screw, to be sure of the enclosure ground).

Not only the anti-oxidant paste, brushing etc., but be sure the breaker and panel

terminals are rated for use with aluminum wire.- (Not all of them are.)

your idea of 2/2/2/4 should be just fine. If you can swing it I would use copper.

Have you try the DIY Chat-room for help on do it yourself work? Here's the link.

http://www.diychatroom.com/f18