If I have a CL200 meter and 200 amp main box can I add a 200 amp subpanel?

Question

If I have a CL200 meter can I add a 200 amp sub-panel to my metal garage? If so what gauge wire do I need?

Answer 1

Yes you can.

You will only have 200 amps, so do not think another 200 amp panel gives you more power.

You will need a load calculation to see how much power(breaker size) you can send.

That breaker size will determine the size of wire you need.

Feeding a 200 amp sub panel with only 40 or 60 amps is okay. You just cannot go over 200 amps.

The cost difference between a small amp panel and a big panel is quite small, and bigger panels are often recommended.

You also need need ground rods for the panel/garage if it is detached from the house.

Answer 2

On subpanels, 200A is just a max rating like your tire speed rating - you can run any feeder size smaller. We often recommend 90A feeder because it uses cheap commodity 2-2-2-4, and that's plenty for just about any garage use. (and if your line of thinking is two EVs, 90A is overkill for home charging - that popular 50A socket is for travel.)

The feeder is protected by an appropriately sized breaker in the main panel. If the subpanel has a main breaker, it's fine for it to be larger e.g. 90A feeder supplying a 200A breaker subpanel - it's only there to be a disconnect switch, a code requirement for outbuildings (note the disconnect switch does not need to be outside!)

A NEC 220.82 Load Calculation must be done on the house inclusive of the new loads you will be adding, and those must be within the system's capacity. You are allowed to account for loads that will not be running at the same time (e.g. if there's only one of you, you probably won't be running the table saw and the band saw at the same time, so you only count the larger one. But you must count the dust collector. But then if you also have a plasma cutter and milling machine that will not run concurrently with the dust collector, you don't need to count that.

Provisioning for EVs is special because of a variety of load shed and EV energy management tech now available. An important note here is you will probably need to run a data cable between your main panel and your EV stations, and that cable can run inside the power conduit (since it is SCADA), so if you expect EVs, use conduit between house and garage so the cable can be added later. I also recommend conduit so you can more easily implement V2H or V2G, which will require completely new types of wire (because it will handle 800V DC battery power). V2H/G/X is going to come up fast because California is mandating the capability for all cars in 4 years.