Need to know what the load amperage is on the 100 amp panel. If interested, open discuss question page.
1/0 copper
AWG #8 copper will work but I personally would use #6 for that long of a run.
For a 120/240 volt sub panel at a full 100 amps at 600 feet you will need a 250MCM copper conductor. This conductor is rated at 265 amps with 90 degrees C insulation for normal distance installations.
6AWG copper wire should be suitable for this need if being run underground in either conduit or direct burial cable. If you go underground I would recommend using 6AWG wire type "THHN/THHW". If this is to be an overhead installation I would also use 6AWG wire but use aluminum type "XHHW". If running underground in conduit you can use 1" schedule 40 PVC conduit but for ease of pull and future expansion I would run 1.25" conduit.
To answer this question a voltage has to be stated.
1/0 copper
You will need to run AWG #4.
AWG #6 will work fine at 100 feet with only a 2% drop in voltage which is acceptable.
You need to be at least 10 feet away from a stop sign.
AWG #8 copper will work but I personally would use #6 for that long of a run.
Normally you would use AWG #6 but for this long run and voltage drop I would recommend you use AWG # 4.
For that distance I would run AWG # 3 copper and install a sub-panel.
15 feet
at least 10 feet.
To remove the door panel you will need to find and remove all screws. Once you have taken out the screws you will need to gently pull the panel away from the door.
to protect our feet from harm, or to keep our feet warm and cozy and away from the wet
A 125 amp panel or subpanel requires # 2 gauge feeders and neutral. (# 2 awg is rated for 130A) However, depending on the existing load in your main 150A panel you likely don't have enough power to operate a 125 Amp subpanel.