Power problems.... Ground, dedicated lines, ect

I am not sure what you mean by a "local" electrician, but there isn't a much simpler task than installing a couple of outlets so if the person is in business and has been doing it for a while it is highly unlikely that he got it wrong. Lights dimming when the ac kicks on is pretty common - there is a high start up current drawn by any motor, usually several times the value of the operating current, causing a voltage drop. This has nothing to do with the new outlets. My guess is that your lights dimmed before you had the new outlets installed and you just paid no attention to it. As an aside, your amplifier probably also has a high inrush current at power up (your uncharged power supply caps are initially shorts) - I got curious as to this and called Mcintosh - their engineer (Ron C) wrote back that their 402 has a 50 amp inrush current - I measured over 20 with an analog meter - which was probably just too slow to catch the full peak. The operating current, also measured is 5 amps).

The voltage drop from your ac coming on is not going to hurt anything. If you heard it in the music then you have a problem with your equipment. It won't damage your equipment and it won't degrade any component in your power supplies.

To see if you are properly grounded and check your outlets there are a number of simple cheap ground check plugs on the market - my guess is HD sells them. You can also take a meter and see if you have 120 v between hot and neutral and 120 v between hot and gnd, and pretty close to 0 v between neutral and gnd.

The street side of your water feed to the house is at earth ground. Find an outlet near your water meter and measure the resistance from the water pipe to the ground at that outlet. Look inside the box and it should be obvious where the new outlets lines are connected to the ground bus. As a pretty good approximation - if you have 0 ohms from another outlet to the water pipe and you have the new outlets grounds connected to a bus bar with a lot of other green wires - your ground is fine. Is this a sure guarentee - no - but, given your description, if this is found to be true, I would stop there.

Square D is a standard for boxes.

Your power company will want to know why you believe that you have a problem. They will likely not send anyone out to look at your power feed just to make sure that your power is ok. If you report that your lights dim when your ac comes on they will also not likely send anyone out , as this is common and does not indicate a problem with the power coming from the company. If you express concern that bad power may be affecting your audio system they will want to know what effects you are experiencing and if you cannot define it as anything other than a change in sound quality, they will likely suggest that you hire a private electrician to check out your power.

If you have a power problem of the nature that you are referring to it is not going to show up as a degradation in the quality of your sound. So long as the voltage at your outlet stays at above 100 volts or so the minor fluctuations from your ac kicking on etc are not going to matter - the power supply caps will hold up the rails.

The idea of ac power problems affecting sound quality is largely misfounded, particularly what you are describing. What you do want is protection against induced lighting damage. Another problem, though rare, and much more practical for audio systems, is where the power actually drops out during high usage times - usually in the summer and not limited to your home. If your power drops out completely and comes back on - say a 2 second interval for eg., and you are at that time listening to music at high volumes, you will likely hear that at the speakers. It makes sense to me that if one is going to use a power conditioner one selects a unit that will also provide power for a short time in such instances - usually accomplished by using a set of batteries as an emergency power source from which to create an ac waveform.

My lights would momentarily dim when my neighbor's AC would kick in. I called the power company one morning and the were there by the afternoon and found a loose connection on the drop to my house. When in doubt, give you power company a call, it won't cost you anything and they just may find a problem on their side.

Also, Square D and others make good boxes and breakers; however, I have found that I have replaced more bad Square D breakers than any other brand.

Newer air-conditioning units typically draw less power than the older ones.

It is not unusual for older homes built in the 1950s or earlier to only have 100 amp service panels rather than the common 200 amp service panels found in later homes.

Either of these could cause noticeable dimming at times as could other major appliances.

New homes and newer appliances should not cause this unless you are using near maximum amperage.

A competent electrician can easily check the majority of electrical connections throughout the house and at the service panel. A competent electrician can also check any/all plugs for proper grounding and proper phase at each wall outlet. You can too if you have a good little meter.

Competent is the key word here.

Typical grounding is done at the service panel where the ground wire is actually connected to the neutral bus. Not sure why exactly but this non-dedicated ground connected to the neutral bus at the service panel is also why grounded components induce more sonic harm than non-grounded. A dedicated ground for your components would definitely be worth considering.

Checking connections from the street to the service panel most likely will require your electrical company to perform this service.

Building a system by laying the right foundation is the only way to go. Electrical is the second most foundational element to a well-thought-out-system.

As such proper line conditioning is mandatory. Again, proper being the key word here because most line conditioners either do nothing or induce their own sonic harm. Moreover, very few will filter out bi-directional noise of which digital noise is. Hence, even if your digital source or amps are attached to good line conditioners the chances are better than excellent that the line conditioner is allowing the digital noise generated by the component to go through the line conditioners back into the wall, all the way back to the service panel, and then induce that digital noise into your other components.

Other things to consider are cryo-treated audio grade wall-outlets, wall plugs, IEC connectors, IEC inlets at the back of the components, internal and external fuses, AC cables, ics, and scs.

Oh, yeah, since I was remodeling a room for listening last year I also had 500ft of 12/2 gauge Romex double-cryo-treated for 4 dedicated lines from the service panel to the listening room.

All of which is relatively inexpensive when compared to the price of one good component. That is except for perhaps the line conditioners.

But since proper AC treatment is one of the two foundational elements to building a well-thought-out system just doing the things mentioned above will produce a pristine and musical system that few can match because of what you did to clean up the AC.

Not to mention you get a bit closer to hearing more of every components' true capability.

-IMO

Power quality is something that utility companies are starting to take seriously as they know the grids are loaded with motors, computers, digital electronics, variable speed motors, etc. What these do is poison entire neighborhoods with noisy ac power making the possibility of electronic component failure higher. They already shell out enough in spoilt food payments during blackouts and foresee more liability with power quality problems as well. Chances are that your utility has a power quality figurehead in a cubicle somewhere and they may very well come out and test. You can do it yourself, but the testing equipment costs thousands of dollars. Or you can try the bigger electrical contractors to see if they offer power monitoring services. But there's really very little you can do on the cheap to correct any utility power issue. The only way is a UPS/Converter system or a shielded isolation transformer for the whole house. You talking Lexus sticker price here.

As far as the air conditioner dimming the lights, that is normal to a certain extent. It the lights really dim, what that could mean is the a/c unit could have a worn-out start capacitor. This capacitor gives the a/c unit the surge it needs on startup and if it's bad then all the startup power is sucked up through your panel. If it's an outdoor unit, that draws a lot of current on startup normally. Also, tungsten light bulbs are very sensitive to small voltage drops so the effect is worse than it seems. One of the solutions is to increase the capacity of the house panel to 200-amps if it's already not that. This will lessen the effects of motor start-ups but not eliminate it. The reason is that the utility transformer serving your house is very stingy with current delivery and there is an inherent large voltage drop at your service panel. It's done on purpose so your house won't see a tidal wave of short-circuit current should one of your household motors short out.

Most power quality problems you can check and correct yourself are: the ground connection from your panel to the water pipe or ground rod should be tight and corrosion free,
the feeders at the main panel should be tight at the breaker lugs, the neutral bus should be bonded to the ground bus, the ground bus jumper bond should be tight, all circuit breakers should sit tight, breakers more than 20 years old should be replaced, all circuits should have their own neutral, all circuits with GCFI receptacles should be on a dedicated circuit. Also, these should be on dedicated circuits: refrigerators, microwaves and window air conditioners. Place these circuits at the bottom of the panel to minimize voltage drop to other circuits, especially 2-pole breakers for well water or septic pumps.

As far as testing, a simple 3-light plug-in tester will tell if you're wired correctly. Here's a hint: wherever you see junction boxes, open them up and make sure the wire connector nuts are tight and the grounding is continuous. Also make sure there's no electrical tape UNDER the wire nuts. That's about all you can do yourself without spending serious money.