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Discussion Starter #1
I'm adding a bunch of machines to my garage and am planning on running many of them off 220V service, but my main house panel is full.

First, I went to check the amount of service coming into the panel and only then did I realize that my panel in my garage is actually a sub-panel. The main panel is outside which has 200 amps. It has two breakers...one 90A for our air conditioner system (I'm near Nashville), and the other is 90A going to the house. Is that enough? Seems small to me.

Anyhow, want to add another sub-panel to the garage for my needs. I'm thinking I want to add the following circuits:
1. 15A-220V circuit for dust collector
2. 20A-220V circuit for machines (saw, jointer, planer) as I'll only be using one at a time.
3. 20A 110V - smaller machines
4. 15A 110V - lights.

So I'm thinking I only really need about 40 Amps total for this panel.

Thoughts?
 

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Is the panel in the garage full? Your new requirements are not that big. Why another panel in the garage?
 

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Discussion Starter #3
Pretty much. I have one 30A circuit that was run to one outlet in the garage. Not sure if someone had an RV or something, but that is the only room I could make in the panel. I was wondering if I should come off that to a sub-panel, or just run a new circuit from the main.
 

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We typically ran job sites from a single 30 amp circuit on a power pole during all stages of construction, often with 3 or 4 trades there at the same time. You would not believe how many adapter wyes were used to provide power to everyone's tools, chargers and yes, radios too.

I would think the 30 amp panel will be enough for your garage if it has enough slots (6 maybe) for your needs.
 

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Discussion Starter #5
It would be pretty easy for me to take that 30A circuit and just make that the source of a new sub-panel.

One of my original questions was concerning the 90A breaker that feeds the house panel. it does everything but the AC units which are run off their own 90A breaker. Is 90A enough for a 3,400 sq ft home? I guess the only big items are dryer and oven.
 

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Yes, 90 amps is plenty. You could even have the A/c on the house panel and still be good to go. Since you don't, so much the better.
 

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It would be pretty easy for me to take that 30A circuit and just make that the source of a new sub-panel.

One of my original questions was concerning the 90A breaker that feeds the house panel. it does everything but the AC units which are run off their own 90A breaker. Is 90A enough for a 3,400 sq ft home? I guess the only big items are dryer and oven.
90A is a stupefying amount of A/C, even for a home that large, even for Phoenix. But that would be just about right for a heat pump with emergency heat for Nashville. Typically that would be 30-40A of actual heat pump and 90A for resistive electric emergency heat (the emerg heat only runs when it's too cold for the heat pump to function, so they get to overlap).

A friend has 140A of emergency heat, but that's in Indiana. His service is "400A" (also called 320A) with dual 200A main panels. Quite the setup, but still not enough for the big on-demand water heaters he'd like.
 
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