Resi electric diagnostic advice

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Corporate Member
My question for the electrical engineers and the like is essentially what diagnostic and investigative residential electric process would you consider for the problems of multi circuit light dimming with loads and discovered hazardous peripheral wiring.

The problem of lights dimming occurs with load changes where the load and lights are on different circuits. Second problem is discovery of concerning wiring. I am looking for advice on how to best systematically troubleshoot the symptoms and evaluate the system for hidden problems.

Sorry, long story....
As background, we are in a house new to us within last year, built in 1997. After move in, discovery of basement water intrusion, mold, now remediated and water intrusion addressed. I mention this because I am now in the process of reconstructing the basement under permit. I’ve found the existing electrical to be sloppy and question whether it could have passed inspection. I have now mostly rewired the basement. I’m at the point of rough inspection later this week. Here is the panel setup: note the rough in wires to the right are mine (I have not tidied the final run by the panel, wires will not be bundled or located where they are now). The sub panel below the main panels is from a generator setup.

Here are the problems encountered:
Hall lights dimmed with various other loads, presumably hvac, power tools, etc. I looked at the entire circuit, replaced fixtures as I checked connections, replaced dimmer and now seems better.
Subesequently noticed mild flckering in other light banks- most ceiling lights in the house. I can’t always identify the load cycling believe it is in the same panel but not the sgame circuit. I think it is only the left panel involved in the symptoms but not yet positive.
This is the left panel:

There was a floor outlet on main floor that wasn’t a UL listed floor outlet. I went to remove it and disconnect the line from the preceding outlet and found this in the wall outlet junction box:

There is a lot going on in the pic, but note the traumatized neutrals with exposed nicked copper. I’ve since rewired the box and placed a junction box extender out to the surface.

So I am wanting to systematically evaluate the system. I am thinking:
Directly inspect all junction boxes.
Check torque of breakers.
Determine if there is an actual abnormal voltage drop under load and, if abnormal, narrow down- power company side, meter>panel, panel, wiring.
I have electric meters including a Klein clamp meter for the panel. Don’t have a megger.
I have seen mention of measuring voltage drop under a known load to search for loose connections.

So, what process would you use to rule out important electrical problems given the intermittent dimming various circuits, identified poor wiring, and two floors of hidden wiring?
(yes, call an electrician for a safety inspection is an option).



Senior User
First of from the sounds of it you may need clean and torque the mains especially the neutral and ground to make sure you have a unimpeded ground path.
If you have aluminum buss connections should get a coat of NoOX or other approved antioxidant after cleaning and before torquing.
The above is huge and usually missed.
A breaker can fail to trip without a good ground path.
Then identify you circuits and clean up your panel.
Then fix problems on the branch circuits as you run into them.
This way it is not as overwhelming

Back when your house was built the electrician was allowed 250 watts per outlet and a maximum of 1500 watts on a 110 circuit.
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