Electrical service questions - revisted

[jpcjguy]

So I had another thread going on my detached garage wiring thoughts but I thought a new one was in order since the other one was kind of all over the place.

After some more "house planning", my stick built 2 story 36x30 garage probably just became a 40x30 pole building..... Somehow I got cornered by the family about a pool, which means the garage just got a lot "simpler".
Not that I mind, the family will enjoy the pool a lot more than just me in the garage.

So on that note, I am revisiting my electrical needs. Originally the thought was to have 200A in the garage by way of an external disconnect box directly off the meter (separate from the twin 200A house panels).

I did go to the county and talked to an inspector and he said that if I have a 200A external disconnect for the garage, I need two more external disconnects (1 for each existing 200A panel in the attached garage). That definitely increases the cost and complexity - let alone the "wall" of gray boxes on the side of the house garage!
From this:

to this:

This brings me to evaluating my electrical needs in more detail. Here is my usage thoughts:

Air Compressor - Husky 60 gallon
Miller 252 welder
Plasma cutter
10k lift
full size refrigerator
Outlets
Lights
Stereo/TV

125A should be more than enough for the above - especially since I cannot use the lift, welder, plasma, grinders, etc. all at the same time.
Where I get confused is planning for potential HVAC. I have thought about a Hot Dawg sealed combustion unit with a propane tank behind the garage to minimize electrical needs, but that adds another set of costs.

That gets me back to thinking a heat pump might end up being the best option. So the question is can I get away with a 3 ton (rough estimate from some online calculators) heat pump on that 125A panel?

As another out-of-the-box thought - I do have twin 200A panels for my house and space in both. So is it possible to run two "sets" of wire to the garage in the same conduit and have a second dedicated panel in the garage just for the HVAC? Have no clue on code on this.....
The details on this thought is that I start with a standard 125A breaker in one of the house panels and run that to a 125A panel in the garage. If, down the road, I do want HVAC and it is too much for my existing 125A panel, I put another breaker (60, 75,100, etc. - whatever the HVAC needs) in the other 200A house panel and run a new set of wires (in the existing conduit) to a smaller second subpanel in the garage and dedicate that for the heat pump? Or should I just drop another conduit in the trench for the future HVAC? Biggest reason is to not have to trench my 200' run again!

 

[brewchief]

You are only allowed one feeder to an outbuilding.

125 amps is a lot of power and I doubt that you will need more.

If you are worried then use a 200 amp panel in the barn and feed it with wire capable of 200 amps, you can reduce the wire size at the house end to fit the 125 amp breaker if need be. This way if you find that you need more power then you could add the disconnects outside at the meter and feed all 3 200 amp panels.

Sent from my XT1254 using Tapatalk

 

[wyliesdiesels]

Another option is to change the meter pan to a meter main with multiple disconnects.

You would of course have to change the 2 house panels to subpanels.

But this would eliminate the 3 disconnects.

 

[sberry]

The 125 will be plenty. The 252 uses about 40 035/c25,,, and only while actually welding. You dont got to squeeze the trigger while comp is running, can always wait a couple minutes in a home shop.

 

[jpcjguy]

Another option is to change the meter pan to a meter main with multiple disconnects.

You would of course have to change the 2 house panels to subpanels.

But this would eliminate the 3 disconnects.

Interesting. can you provide more detail on what size/type meter main I would need if I am supporting 3 "200A" panels? a search came back with tons of sizes/types/etc.

Thanks!

 

[jpcjguy]

You are only allowed one feeder to an outbuilding.

125 amps is a lot of power and I doubt that you will need more.

If you are worried then use a 200 amp panel in the barn and feed it with wire capable of 200 amps, you can reduce the wire size at the house end to fit the 125 amp breaker if need be. This way if you find that you need more power then you could add the disconnects outside at the meter and feed all 3 200 amp panels.

Sent from my XT1254 using Tapatalk

That was another option i was thinking - setup for 200A with wire size and then just use the 125A breaker in one of the panels to start. I assume that if I end up needing the 200A external disconnects and my "wire" from the detached building is a little short to go to the disconnect, I can do a splice to add a few more feet if necessary? Where would that have to go - in a junction box somewhere?