You've hit the nail on the head: this is almost certainly a loose neutral. The reason it's happening the way it is, and why it's so confusing, is due to how the load balancing changes when you add those individual circuits. Let's break it down

The Core Issue: Floating Neutral

A loose neutral creates what's often called a "floating neutral." Here's what that means: No Reference

A good neutral provides a stable, low-impedance reference back to the transformer supplying your service. It's the "zero point" for both legs of your 240V service. When the neutral is loose, this reference is compromised.

Voltage Division

Instead of a direct path back to the transformer's neutral, the current must find its way back through other loads in the house. This means the voltage will divide unevenly between the two legs based on the impedance of the loads connected to each leg.

Impedance, Not Just Amperage

It's critical to understand that impedance matters more than the amperage draw. Impedance is the total opposition to current flow, including resistance and reactance (which comes from things like motors and fluorescent light ballasts).

Why It Appears Normal With Breakers Off

When all breakers are off, you're measuring the open-circuit voltage from the transformer. There's no current flow, so the loose neutral isn't affecting the voltage readings much. You're essentially seeing the secondary voltage from the transformer before any load is applied.

How Adding Load Creates the Imbalance

Here's where the magic (or rather, the misery) happens:1. Initial Imbalance (220V/20V)

When you turned on the circuit powering the kitchen and bathroom outlets, you likely had a significantly different impedance on that leg compared to the other leg (which had no load). Let's say the kitchen and bath outlets represent a fairly low impedance (higher current draw for a given voltage). Because of the bad neutral, that leg now has a lower voltage drop (20V). The other leg has a higher voltage drop across its portion of the circuit, resulting in 220V. The "extra" voltage is appearing on the leg with less load because the loose neutral isn't allowing the current to easily return to the transformer on that side.2.

Progressive Imbalance (115V/124V)

As you turn on other breakers, you are changing the impedance on both legs. The voltage will shift up or down on each leg depending on what is connected to it. The fact that you are getting 115V/124V suggests that the overall impedance on the leg with 115V is lower than the overall impedance on the leg with 124V.

Where to Look (Prioritized) Meter Neutral

As you suspected, this is the prime suspect. The neutral connection at the meter base, especially where the neutral wire enters the meter socket, is a common failure point.

Important



Call the utility company. Do not attempt to work inside the meter base yourself unless you are specifically authorized and qualified to do so by the utility. This is dangerous and could be illegal. Request they check the neutral connection at the meter and at the transformer. Neutral at the Service Entrance

Where the neutral service entrance cable connects to the neutral bar in the Pushmatic panel. Look for corrosion, looseness, or signs of arcing.

Pushmatic Neutral Bar

Examine the neutral bar itself in the Pushmatic panel. Look for cracks, corrosion, or damage. Also, check that the grounding conductor (to ground rods, water pipe, etc.) is properly connected to the neutral bar.

First Outlet on a Circuit

While unlikely to cause voltage imbalances at the panel, carefully inspect the wiring and neutral connections at the first outlet on the problematic circuits (kitchen/bath, and the other circuits you tested). A bad connection there could contribute to the overall issue, though it's less likely to be the primary cause.

Troubleshooting Steps (After Safety First)1. Document Everything

Take detailed notes of the voltage readings with different combinations of breakers on and off. This helps you track the changes and narrow down the problem. Take photos/videos of the panel/meter to ensure you remember what you saw.2.

With the Utility's Permission, Verify the Neutral Connection at the Meter

After the utility has verified the service neutral, you can confirm that the voltage readings stabilize before touching anything else. If the problem is resolved, the utility's work was the fix.3.

Systematically Tighten Connections

With the main breaker off, go through the panel and carefully tighten all neutral connections. Use a torque screwdriver to ensure proper tightness according to the manufacturer's specifications.4.

Load Testing (If Necessary and Safe)

After carefully inspecting and tightening connections, and with the main breaker back on, use a clamp-on ammeter to measure the current on each leg of the service (each hot wire coming into the panel). The current on each leg should be reasonably balanced. A significant imbalance indicates a disproportionate load distribution, which can exacerbate the problem of a loose neutral.5.

Voltage Drop Testing

Once you get the neutral issue resolved and are getting consistent 120V readings at the panel, do a voltage drop test on the problematic circuits (the kitchen/bath outlets, and the others). This will help you identify any high-resistance connections further downstream on those circuits.

Important Safety Notes ELECTRICAL WORK IS DANGEROUS. If you're not 100% comfortable and qualified to work on electrical panels and service entrances, do not do it. Call a qualified electrician. Always turn off the main breaker before working inside the panel. Even with the breaker off, there is still voltage at the main lugs. Wear proper PPE (Personal Protective Equipment) including insulated gloves and safety glasses. Double-check everything before restoring power.

Good luck tracking down this tricky problem! The methodical approach I outlined will help you isolate the source of the loose neutral and get the old lady's electricity back to normal. Flag for review