The ideal solution is to use a thermostat with multistage capabilities that would only bring on the extra banks of heat strips as needed. The 1st 10KW could be brought on by one contactor through W1, the 2nd 10KW contactor brought on by W2.
If a multistage thermostat isn't practical time delays or outdoor thermostats could be used to control when the 2nd bank of heat is activated.
Another strategy with heat pumps involves setting up one 10KW bank of heat connected to W1 of the thermostat and the other 10KW bank being activated by the defrost board of the heat pump. If the heat pump can't keep up the thermostat will call for 10KW heat, when the heat pump goes into defrost the other 10KW will come on. Once the heat pump catches up electric heat is dropped. A simple wiring change achieves this, no additional parts required.
Im not disagreeing with a word you just said. Your obviously more knowledgable on the subject than me. I was commenting on a earlier post in the thread were someone said they always change seq. with contactors when theirs a problem. I wouldnt thank thats a good idea especially when you suspect ambient heat is preventing the seq. from opening.
Peak demand is figured over a 15 minute period, not at any one instant. It only affects those who have smart meters with peak pricing plans and certain commercial customers. IMHO it's better to split the heating load into stages controlled by the thermostat.
To clarify what i was saying the post i commented on didnt mention staging. And as you said electric plans vary we dont know this homowners plan, nevertheless sequencers werent designed to keep breakers closed since theirs no difference on start up amps so i assume their designed to control peak wattage. Plz correct me if im wrong but most pairs of resistance heaters are on a separate breaker than the blower.
Normally there are 2 60A double breakers. One set controls the blower and the 1st stage of heat strips, the 2nd set controls the 2nd stage of heat. Air handlers typically use W1 and W2 for heat, one terminal per bank of heat. A 2 stage thermostat can bring on W1 most of the time, and only kick on W2 when W1 can't keep up.