I find it surprising that service panels don’t have more extensive protection features. I would like my main breaker to trip under any of these conditions:

- Sustained overvoltage. Any overvoltage lasting too long to be handled by a surge protector should trip the main breaker.

- Sustained undervoltage. Some devices don’t like this.

- Phase error. A two phase main should detect incorrect phase-to-neutral voltages and incorrect phase-to-phase voltages. A three phase main should also detect incorrect phase sequence. This should also catch some cases of a disconnected neutral.

- Excessive neutral to ground current. In the US, for reasons I personally strongly dislike, every “service” has a connection from ground to neutral, usually in the meter box or the main panel. Various errors can cause substantial current to flow through this connection and can be dangerous. For example, if a house and the utility both have excellent grounds but the house’s neutral feed breaks, all the voltages can be close to correct and the house’s neutral current will return to the utility through ground. This is dangerous and will not be detected by common equipment. (A whole-house residual current detector would satisfy this, too. I think these are used in Europe.)