On Fri, 20 May 2016 04:41:58 -0700 (PDT), bob haller
wrote:

On Thursday, May 19, 2016 at 9:25:00 PM UTC-4, wrote:
On Thu, 19 May 2016 17:55:31 -0700 (PDT), bob_villain
wrote:

On Thursday, May 19, 2016 at 7:01:18 PM UTC-5, John G wrote:
I want to put a sub-panel in a connected garage. Can I use 6-ga. 3-wire to supply a panel with 4 breakers (20A each)? Do you have to consider the possible use of all of the circuits carrying the maximum load? Thanks!

You do need to consider what the total load of the panel will be at any given time. Will you be running machines constantly or intermittently? You do not have to total up the rating of the individual circuit breakers.

You need four wires for a sub-panel and I think a ground rod for lightning protection is a good idea.

John Grabowski
http://www.MrElectrician.TV

Thanks John, besides a circuit for fluorescent and LED lighting...there will be only one (table saw, miter saw, grinder, etc.) used at a time.

If you do run that #6 in pretty much anything but Romex, (limited to
the 60c column) you can hang a 60a breaker on it and put in a pretty
nice sub panel. THHN in pipe would be an example of a wiring method
that would get you into the 75c column (65a). At that point I would be
looking at a 6 or 8 slot panel for a few bucks more than that 2/4 GE I
linked the other day.


always better to go BIG when planning electrical upgrades. while up sizing may cost a bit more, its cheaper than upgrading later

"why is there always enough money to do something over, but never
enough to do it right?"