What to do if your whole house starts flickering electrical

1. Damage Control. Avoid using expensive equipment (like computers or flat-screens) on any circuit where you see flicker (that turns off with the same breaker as a light that flickers). Flicker is often due to a failing neutral connection, and eventual total loss of a neutral can put 2x voltage across the outlets in some wiring configurations. This can destroy electronics.
2. Try to identify at least one circuit (lights and/or receptacles with lights plugged into them, all controlled by a single circuit breaker) that does NOT flicker, ever. Most likely, a newer kitchen or bathroom circuit, or something maybe near the breaker panel in the basement. If you cannot find any circuits unaffected by flicker, call PECO for free service that will rule out a fire-damaged or otherwise loose connection on their lines. Look outside and try to tell whether your service drop from PECO lines comes in a) from overhead lines on the street, via a tap from the PECO lines that is independent of other houses (or shared with only one neighbor), b) via a common cable running along the back of all houses on your side of the block, or c) entering your basement from underground, via a big rectangular steel box.
3.  If your service drop is from overhead and shared down the block, the fire very likely DID affect you, and you can chat up neighbors to see if they’re having the same trouble, while you wait for PECO to confirm/deny this. If it is overhead but independent of neighbors or only shared by one neighbor, then the fire is probably irrelevant. Still, you may have a loose connection to PECO lines or there could be trouble on PECO lines that they can rule out for you, for free. Look up and down the block for signs of obvious damage to the PECO lines that you share with your neighbors.

   

   A run of 240V, single-phase utility lines behind a row of twins has come loose from its mechanical supports on one building. Resulting strain on splices may cause intermittent or arcing connections that would result in flicker for affected buildings.

   

   Corrosion and/or loose terminations at the service equipment could cause intermittent and/or arcing connections and result in flicker on alternating rows of breakers served by the loose/corroded conductor.

   
   
   
4. Connect a microwave, vacuum cleaner, or space heater and see if turning it on/off contributes to flicker. Does it affect more than one circuit, or just the circuit where you plug it in?
5. If more than one circuit breaker is affected, but NOT all circuit breakers, try to determine whether the flickering is affecting breakers on alternating rows of breakers. Because the twin (and opposite) phase conductors (aka ‘hots’) feed alternating rows down the two columns of breakers in your panel, only even rows or only odd rows affected would indicate that one, but not both, of the phase conductors somewhere between PECO and your main breaker has a loose connection at one of its terminals. It is rare for both phase conductors to go loose at the same time, so a ‘loose hot’ condition appears with this characteristic symptom of alternating rows totally out, or flickering.