I am adding a 125 amp subpanel to the far side of my house. I need to
add a disconnect breaker near the new subpanel...but...I can not find
anything rated at 125 amps at either Home Deport or Lowes. The
largest they have for disconnect is 70 amps for a spa setup.?

Do I need to find a electrical supply house for this...or is there
something I am missing at Home Depot ?

Also...I am running a feeder line from the main panel to this
subpanel...the run is about 100 ft...can someone tell me what the code
is regarding the size of wire needed for this run. The retired
electrician at Home Depot says a 4awg three connector cable will be
fine...it is being run through 1" EMT across a flat roof with rain
tight compression connectors ?

Thanks, Tim