Oilpan4 wrote: ↑
Thu Jan 30, 2020 12:44 am
I have a cheap $160, 16 amp 240v duosida evse that I have had for a year and a half.
From what I have heard, that is about the average life expectancy for cheap EVSAs. Maybe you will be lucky and get 3-4 years out of it. A good one should last over 10 years.
If the panel is full add a sub.
I said if the service is full, not if the panel is full. Adding a sub panel allows you to add more breakers, but it won't increase the capacity of the service (in Amps). Increasing the service size likely means dragging in a new wire from the transformer (unless the one you have happens to be oversized) which is going to be very expensive (especially if you have underground wiring).
No need to do a load analysis on residential. That's what the main breaker is for. If anything switch breakers around to ballance both legs of 120v current flow.
The main breaker is designed to protect you from exceptional circumstances, not to protect you from blindly adding additional circuits until you are over capacity. Having any circuit breaker blow is a warning that something isn't right, but having the main breaker blow is a sign that something is very seriously wrong. It should not be relied upon as a test that everything is okay.
Panels are designed to be safe as long as codes are followed. That's why they are a certain physical size, have a max main breaker rating and only allow a certain numbers of circuits to be installed.
That is the key. Part of the code requirement is that you not put more load on the panel than the service was intended for.