Why does the main circuit breaker trip but not the smaller branch circuit breakers?

As others have mentioned, the main is sized less than the sum of the branches; if all the branches pull heavy loads, you can exceed the main without exceeding the branches, and the main will trip. If this is the cause, you can; Accept the overload, and be ready to flip your main breaker when it happens.

Are lights and outlets on same circuit?

My short answer to the question is that “Yes, lights and power outlets (a.k.a AC receptacles) can be on the same circuit controlled by a circuit breaker, especially in a single family residential house”.

Why does main circuit breaker keep tripping?

There are a number of reasons why the main breaker might trip. Lightning strikes, power surges from the utility company, or an overload to the electrical panel can all cause the main breaker to trip. The problem may involve a short circuit in the main panel, a failed main circuit breaker, or another serious problem.

What causes a main circuit breaker to trip?

A circuit breaker will usually trip when there is an electrical fault that could cause damage to the circuit. This is usually an excess of current, a power surge or a faulty component.

Can you put all lights on one circuit?

The Electrical Code allows 12 devices on one 15 Amp circuit. Devices are lights and receptacles, not switches. “Trade practice” frowns on all the lights on one floor to be protected by one breaker. If the breaker trips, or is switched off for any reason, the whole floor is darkened.

How many can lights on one circuit?

There is no limit to the number of lights on a circuit. The load of the fixtures is what determines how many lights a circuit can accommodate. A conventional 15A circuit can have up to 1400W of lighting loads connected to it. A 1400 Watts lighting load can accommodate one 1400W fixture or fourteen 100W fixtures.