On Fri, 21 Mar 2014 04:12:51 +0000 (UTC), DerbyDad03
wrote:

I was looking in a residential service panel today. 150A, 30 circuits, 15
per side.

For the circuits that run down the right side of the panel there is a bus
bar that holds the ground wires and a separate bus bar for the neutrals.
The ground wire to the water meter was attached to the neutral bar.

There should also have been a green tinted screw or a dedicated strap
bonding the neutral bar to the can and grounding bar since this seems
to be the service panel.

For the circuits that run down the left side of the panel there is a single
bus bar and the grounds and neutrals from each circuit are paired up under
each screw.

This is a hazardous practice. A loose or faulty connection could cause
the ground to become hot through the neutral with current flow. Most
panels allow more than one grounding conductor per grounding bar
terminal.
Neutral bars sometimes are listed for more than one neutral.
I have never seen a panel approved to mix neutral and grounding
conductors in the same terminal.

A strap connects the neutral bus bar on the right side to the
neutral/ground bus bar on the left side.

This is commonly done to supply the needed number of neutral
connections and usually allow the circuits to be reasonably close to
each other.

Why are there 2 separate bus bars on one side but a combination bus bar on
the other? Aren't they all electrically at the same point? If so, why
separate them on one side?

Think grounding conductors to grounding bar, neutrals to neutral bar
but if a service panel the grounding conductors may be terminated to
the properly bonded neutral bar.
--
Mr.E