On Tue, 29 Dec 2015 16:53:34 -0700, Don Y
wrote:

On 12/29/2015 4:41 PM, wrote:
On Tue, 29 Dec 2015 12:01:35 -0700, Don Y
wrote:

On 12/29/2015 10:54 AM, John G wrote:

Took some time this evening and checked the voltage on several outlets
in my shop and to my surprise I found several at 117v and several at
125v. Then I noticed that the difference voltages were on different
circuits. Then taking a look at the breaker box I noticed that each 125v
would be directly across from another 125v breaker and the same for the
117v circuits.

Well, that gave me a good clue as to what was happening so I opened the
box and took a look and checked some voltages. I took a picture, added
the voltages to it, and uploaded it to one of my domains at
http://www.dongares.com/breaker.html so go and take a look.

As I have previously mentioned in an earlier post this is a sub-panel
which is supplied from the main panel in my home via a 100 amp breaker.
I have not taken time to check but I am almost willing to bet that I
find different voltages in my home also. It is going to be interesting
to see if what I am getting from the street to my home is also different
voltages...how you want to bet?

The home was built in 1993 and these differences have never caused a
problem but it will still be interesting to see what is actually happening.

The grounds in a sub-panel are not to be terminated on the neutral bar. Remove the green screw and install a separate ground bar in your sub-panel for the grounding conductors.

Did you contact the power company? A problem with one of their lines may be causing the voltage drop.

John Grabowski
http://www.MrElectrician.TV

Is that all you saw ;-)

Are you referring to the two different brands of circuit breakers?

No GFCI's and I suspect there may be some need for them in a "shop"
(without knowing what else is in the building).

Two 20A breakers are unused -- both on the same leg (a likely place
to suspect a sizeable imbalance)

That is why I asked about the feeder size.

The bottom right two-pole breaker feeds a 220V circuit wired black/white
(i.e., the safety "ground" acting as neutral for any appliance
fed from that branch)

There is plenty of 240v shop equipment that doesn't use a neutral.

You don't know that looking *in* the panel. Put a cover on the terminal
Jbox (because you are no longer using that piece of gear) and the
next guy coming along opens it to find white (untaped), black and
copper. Do you think he's going to assume the white is really
a hot and this is a 220V feed? Or, that it's yet another 110V, 20A
circuit?
When you decommission a 2 wire 240 volt circuit that does not use a
240 volt specific outlet you ALWAYS disconnect it at the breaker. That
way there is no chance of ambiguity.
A good idea on any "dedicated" circuit too. If there is nothing else
on the circuit don't just wire-nut it off in the jbox. Either
disconnect, or better yet label and lock out the breaker involved.