The One with the Blackout - S1-E7
Corrected entry: Chandler calls Monica to tell he's trapped in an ATM vestibule with Jill Goodacre on a mobile phone, however Monica answers by picking up the house phone. In a power blackout, the phone wouldn't have any power so Chandler shouldn't be able to reach Monica.
The One with the Blackout - S1-E7
Corrected entry: When Joey walks in holding the candles and says his old roommate was Jewish, Joey's actually holding a kinara for Kwanzaa not a menorah for Hanukkah. There are only 7 candles on the candle holder that Joey is holding and there are 9 on the menorah.
Correction: The 7 or 9 branches have different meanings. The 7 branch menorah represents the one which stood in Jerusalem's temple. The 9 branch is called a chanukiah, and represents the Hanukkah miracle.
Correction: Phones don't lose power during blackouts - regular landline phones are powered over the phone lines from the telephone exchange, which will have backup power available. Cordless phones would lose power, as the base station needs to be plugged in. But in this case Monica is using a wired phone. It's recommended to keep a wired landline phone in the house specifically to use in case of a blackout, as she clearly does.