Can I upgrade my main panel?

MarkinTexas · 01-21-2009, 02:25 PM

Sorry for the basic question, but here goes...

I just bought a house (built in 2002) with a 150 amp main panel. The panel is completely full and I'm now in the process of wiring my detached garage. Obviously I need to install a sub panel, but I'll need it to handle the various garage circuits including a 220V outlet (40amp) plus have the capacity for a 500sqft addition and a pool.

My question is this: can I upgrade the main breaker to something more than a 150amp so I can run a 100amp sub panel? The service to the panel is 2 2/0 Aluminum. According to what I could find, 2/0 AL is good for up to 150A, but since there are two service feeds, does that mean it will support up to 300A or that simply because of the 220V circuits? I'd like to upgrade the main to at least 200, can I do that simply by swapping the main breaker or do I need the electric company to upgrade my service?

Thanks for your help.
Mark

Bob Mariani · 01-21-2009, 02:46 PM

you need to replace the panel or add a new 200 amp disconnect outside with two main breakers to feed the old and the new panel. But you also need to replace the service feeders to 4/0 to get the 200 amp capacity. The power company will access anything they need changed without any costs to you. But do you need it. Run a load demand on the house and see what you total power requirements are. I suspect you will find that 150 amp is sufficient.

Gigs · 01-21-2009, 03:35 PM

You can run a 100 amp subpanel on 150 amp service.

rgsgww · 01-21-2009, 04:07 PM

The poco will use 4/0 AL most likely for 200 amp service. You do not have the sufficient service. They would need to run new wire.

Do a load calculation on everything off your main. Consider the possible loads, expansions.

No, they don't "double" up. It's the same ampacity per leg.

Magnettica · 01-21-2009, 04:41 PM

What you need to be concerned with is the size of your feeders. They are the wires from the load size of your meter pan to the 150 amp main breaker in your panel. They'll need to be either size 2/0 copper or 4/0 aluminum for you to upgrade to 200 amps. Is the power from the power company coming to your house overhead or underground?

MarkinTexas · 01-21-2009, 05:37 PM

Quote:

Originally Posted by Magnettica

What you need to be concerned with is the size of your feeders. They are the wires from the load size of your meter pan to the 150 amp main breaker in your panel. They'll need to be either size 2/0 copper or 4/0 aluminum for you to upgrade to 200 amps. Is the power from the power company coming to your house overhead or underground?

Thanks for all the info (and quick, too!). This is what I suspected. The feed from the poco is underground.

chris75 · 01-21-2009, 07:02 PM

First thing I would do is hire someone to do a load calculation to see where you stand at the moment and see what your future needs are, you may not even need to upgrade your service.

chris75 · 01-21-2009, 07:03 PM

Quote:

Originally Posted by Gigs

You can run a 100 amp subpanel on 150 amp service.

Maybe, maybe not, all depends on the loads.

MarkinTexas · 01-22-2009, 11:15 AM

Currently, the 150A panel is fine for the load. However, I need to add a number of circuits for the garage /workshop and I'll be adding a pool and an addition later this year. Since I need to add a sub panel to add the garage circuits, I wanted to go ahead and upgrade the service for my future needs while I'm into it.

Thanks for all the help guys!