Install Subpanel or upgrade service?

Old 07-01-15, 02:23 PM
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Install Subpanel or upgrade service?

I have 150 amp service coming into my house.

My breaker box is full--no available breakers.

I will want to add two 240v appliances: a split system A/C and an electric water heater.

How do I know if I need to upgrade my service or if I can just add a subpanel?
Old 07-01-15, 02:26 PM
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I would start by adding up the draw of the appliances you intend to have when finished as well as the total draw available through your current breakers.

In other words, start figuring out what your needs are to evaluate whether the service upgrade is needed.
Old 07-01-15, 02:29 PM
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You can do a "demand load calculation". Google will list many guides and calculators to do the figuring.

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