On Wed, 16 Mar 2016 16:33:45 -0700 (PDT), DerbyDad03
wrote:

On Wednesday, March 16, 2016 at 6:40:02 PM UTC-4, Mr Macaw wrote:
On Mon, 14 Mar 2016 04:22:42 -0000, wrote:

On Sun, 13 Mar 2016 18:41:50 -0000, "Mr Macaw" wrote:

The problem is when there is more than one circuit in the box or when
people assume all white wires (neutral here) will be grounded. If you
open up that wire nut only one of those wires with be ground, the
others may be at full line voltage through the connected load.

Firstly, why on earth would you have more than one lighting circuit? Secondly, if you do, simply use a multimeter!

They tend to use the large ceiling boxes as junction boxes and there
may be a number of circuits radiating from there. We don't have loops.

How weird. My electricity travels to each lightswitch in turn, then IF the switch is on, then there is electricity at the light. Why send the electricity to the light, down to the switch, then back up to the light?

Because it's often easier and often saves wire.

Source wires to switch box, hot switched, then to fixture box:

http://i.stack.imgur.com/IcZAP.png

Source wires to fixture box then *hot* wire to switch box and back to
fixture box:

http://www.how-to-wire-it.com/images...r-at-light.jpg

It all depends on the physical layout and how easy it is to run the wires.

The (well, one good one anyway) reason is it is easiest to make your
runs across the ceiling from light to light, and then just drop the
switch lead down the wall to the switches.

If you are separating lights from other loads, the lighting wires are
in the ceiling, and the other load wires run in the floor, and up to
the outlets. That way you are not running wires through the walls and
getting tripped up by doors, heating ducts, and plumbing in the
walls.. Of course this is assuming not "on-slab" - with a basement or
accessible crawl space.