This is now a year old thread but after reading through the comments on the question, this almost certainly sounds like the building has developed bad wiring that is causing arcing, and constantly tripping the Arc Fault Circuit Interrupters.

The personal appliances may not be directly involved in this, other than completing the circuit, and allowing defective but idle building wiring to expose itself.

AFCIs are supposed to trip over and over until the real problem is fixed, because arc faults due to defective wiring will not go away on their own, and replacing the AFCIs themselves will not fix anything, unless it is in fact the AFCI that is arcing internally.

The building wiring can go bad all by itself even if it was originally installed and inspected properly, if there are external conditions that cause corrosion of the metal inside junction boxes, such as flooding, high building humidity, or exposure to salty ocean spray.

External forces such as earthquakes can also cause loose wiring arc faults due to pulling on wires and loosening of screw lugs and wire nuts, when buildings flex but don't collapse.

Really the solution is for the electrician (or homeowner if the jurisdiction allows it) to check the entire length of each faulting circuit, open the junction boxes from the breaker panel to all the endpoints, and check everything for loose wire nuts or loose screw terminals.

Since wire nut connections cannot be examined installed, they will all need to be removed to examine the wire ends and then retightened. All metal to metal wire contact and the inside of the wire nut should be shiny. Though if you're going through all this, it may make more sense to just replace all wire nuts with new and not bother reusing the old ones.

For push-in spring terminals, the wire end should be released, examined for corrosion or burn marks, reinserted into the spring terminal, and checked for firm anchoring with light tugging.

Outlet sockets and lamp fixtures can also arc inside where the plug or lamp base is inserted.

Check any device plugs for dark burn marks on the blades, or darkened scorch marks on socket faces where the blades go in. Replace both the burned wall sockets and the device plugs, not just one of them or the problem will restart.

Likewise check all lamp sockets for blackened or pitted / welded contacts and replace both the socket and lamp if found, because arcing causes unwanted heating and building fires.

If the problem persists after checking all easily examined junctions and terminals, the arcing can hidden be inside enclosed circuit devices that are not designed to be opened and examined, such as switches and receptacle sockets that are riveted/glued shut, or their hidden internal push-in spring terminals. It may be necessary to replace all of these circuit devices to see if the ACFI tripping finally stops.

Ideally if the circuit tripping occurs when some specific thing happens, this will likely lead you to the quickest resolution, such as "when I turn this room light on/off, the AFCI trips"... so in order of complexity, check the lamp socket, the lamp base, try replacing the sealed light switch with a new one, and then move on to examining all the building wiring end-to-end from the AFCI to the lamp, including in the lamp fixture itself.

Finally, if possible try to locate the cause of the external stress / damage factors, and attempt to prevent or alleviate them.

In some cases the building wiring may need to be changed, such as switching to using watertight and gasketed conduit to protect wiring that corroded due to high humidity exposure.

Wiring strain damage caused by earthquakes and building movement can be reduced by leaving coiled slack in the walls or junction boxes, so that the wiring has room to flex and move without pulling junction or terminal connectors apart.

Wiring and devices that are exposed to frequent vibration, position adjustment, or heating and cooling cycles can also develop loose and arcing connections, and may require design changes or more frequent inspection for damage.

It could have to do with the trip curves of the breakers, and/or the ambient temperature differences between panel locations.

Trip Curve

For example, let's say all the circuits on Phase A are drawing 3 times the rated current. The trip curve for these breakers, say they will trip between 10 and 30 seconds at 3 times current. So the total current on Phase A at the main panel is 270 amperes, or 2.7 times the rated current (100 A). The trip curve for the breaker in the main panel, says that it should trip between 12 and 35 seconds at 2.7 times current. If the breaker in the main panel is a bit more sensitive, you can see that it might actually trip before any of the secondary breakers.

Ambient Temperature

As well as a trip curve, circuit breakers will also have an ambient temperature curve. Breakers are designed and calibrated to operate at 40°C (104°F) ambient temperature. If the breaker is operated at an ambient temperature of -10°C to 24°C (14°F to 75°F), the breaker will be able to carry more current. However, if the breaker is operated at an ambient temperature between 41°C to 60°C (106°F to 140°F), it will carry less current and could lead to nuisance tripping.

For example, if the 100 ampere breaker is operating at 140°F ambient, you might find that it actually trips at only 85 amperes.

High Altitude

When breakers are installed at higher altitudes, the current has to be adjusted due to the reduced cooling effects of the thinner air. According to the documentation I could find, the adjustment multipliers are as follows:

• 0 - 6600 ft. (0 - 2011 m) -> 1
• 6600 - 8500 ft. (2011 - 2591 m) -> 0.99
• 8500 - 13000 ft. (2591 - 3962 m) -> 0.96

If you were installing a 100 ampere breaker at 10,000 ft., the breaker should only be expected to carry 96 amperes (100A * 0.96 = 96A).

Though in your situation, the breakers are likely all installed at a similar altitude. So this it likely not the problem, unless the air near the main panel is significantly thinner for some other reason.