Originally Posted by jpalarchio
I guess my question was more along the line of how do I know that I have actual capacity to put in a 50 amp connection?
Obviously the sum of the breakers far exceeds the main breaker and the concurrent usage of devices in the house is fairly small (we're not running all the lights, microwave, dryer, stove and AC all at once 24x7).
How do I know whether 50 amp or 30 amp is appropriate? Do I need to be concerned about drawing too much amperage and tripping the main breaker?
My thought was to install the 50 amp spa panel with GFCI in the garage (about 10 ft of wire from the panel) and then either a 50 or 30 amp breaker in the panel.
The unused spots in your panel are there for a reason . . . . . to be properly used for future expansion. Heck, a builder could kindly fill every one from the git-go.
You do not want to exceed 80% of that main 150A breaker.
One way to know this is to measure the 'draw' with everything in the house on. Equipment nameplate data will need to be added to what can't be turned on during the draw test.
The tool to use is:
You will want to be comfortable using the meter before ever attempting the test. You will be never be closer to the full current supply available to your house than during this check. Possibly 1000's of amps. Not to scare you, but you must not be insecure with the task.
Shut off the main power the first time you ever pull off the panel cover. I'd wear leather gloves for physical and electrical protection. Look for improper wiring methods that may get you in trouble. AKA crappy workmanship. Shut off every branch breaker in the panel.
Locate the two service wires coming into the main breaker. There must be room for the clamp meter to clamp around each wire. Clamp it around one wire. I like to place it at a viewable position.
Main back on. Then each branch breaker back on. Turn every load on you can and take an amp reading. You can gingerly move the meter to the other service wire, or you can reverse the procedure. Shutting off each branch breakers, swap the meter and repeat the above.
If this makes procedure makes you queasy, you can add the loads mathematically using nameplate data for all the appliances. This will give you an elevated number as the nameplate data is using stated as 'full load'.
Some safe steps:
Avoid shutting off/on the main breaker under load with the cover off.
Don't have any distractions.
Watch for wires near the panel cover screws.
Don't sweat the 50A breaker. The panel and breakers will protect you from overloading anything.
The remote Spa panel is the way to go.