You are correct, that is rubbish.
It's simple, in order for the line voltage (normally 120 or 240 volts) to be that low, none of your other appliances would operate either, such as your lights or TV.
I'm assuming an electric stove.
For a gas stove, yes, the gas pressure could be low due to a lot of usage. But ovens are controlled by a thermostat, the burners turn on/off in order to keep the temperature at the proper point. If the gas pressure were too low. the burner would not light at all, there are safety interlocks for that. And if the burners lit they would produce enough heat to kook something in the normal time.
In theory if enough people are using large volumes of electricity then the voltage at the oven might be lower which could limit the power to the oven but I don't think that is likely.
This is strictly a matter of the grid that you are connected to, the wire sizing, the total load on the system and the amount of electricity your oven needs. There is no reference that can address this.
The very best indication of very low voltage is a dimming of the lights. In an extreme case you get what is called a brown out. Unless you lights are not as bright as usual then the problem may be the thermostat or even one of the heating elements in the oven may at burned out.
Assuming electric...
Get a voltmeter, and put on the feed to your stove / oven. If it drops by more than 10%, then you either have bad wiring, or the utility is severely overloaded.
Please note that power dissipated in your oven is proportional to voltage^2, so a 10% drop in voltage is a 19% drop in heating rate.
More than likely, you had more food, the food was colder when starting, or you were simply tired of waiting.
Electrical equipment must receive the correct voltage to work properly. Therefore, power companies regulate the voltage and it will be almost constant regardless of the load so long as an overload doesn't occur. If there is an overload the circuit will open and you'll have no power.
He is absolutely correct. Everyone in the UK is using gas and electric at the same time on Christmas day. Particularly with gas the supply can be lower.
UK
Whilst cooking the fast today,it took longer, my dad says that this because of other people on the same network has depleted the energy to such an extent that the oven never reaches temperature.
I think this statement is rubbish
Please let me know plus references he is a stickler for back up data.
Thanks Jack.
