Planning for Future Expansion

[JhnRX7]

I am in the process of preparing my permit package for the addition of a 100A sub panel to my attached garage. The 200A main house panel is in the basement at the opposite corner of the house so it will be about a 90' run from the main panel to the new sub panel.

I will be removing all the drywall in the garage to run the new circuits then insulate and re-drywall when I am done. Seeing as I will have everything exposed, I like to future proof as much as possible at this point. I have two situations I could use some advice on:

1) In the immediate future (within the year) I plan on installing a shed on my property and I would like to run power to this shed. The shed will be installed near the attached garage and I would prefer to run the wires in the garage walls and penetrate the house to a box outside before I close the walls up. The shed will get a 30A 240V circuit (air compressor) and a 20A 120V circuit for a couple convenience outlets. I am looking for recommendations on the best type of outdoor junction box to use for this purpose. Once the shed is installed, I would run underground in conduit from this junction box to the shed. This circuit would not be landed in the garage sub panel until the future shed work is complete.

2) In the distant future (5 years or so) I plan to build a detached garage next to the attached garage. Assuming this sub panel could handle the load, is it possible to run a second sub panel to a detached garage off a sub panel? If so, I will likely run some conduit in the walls to allow for future wire runs with this in mind.

Question #2 also applies to the shed question as it would be easier to do a single run to the shed and install a small panel in there.

 

[yatg]

Can't run multiple circuits to a structure.
You'll need to put a small subpanel in the shed.
Use a 60A A/C disconnect on the outside of the attached garage.
A GE with a pullout is $9 at home depot, a Square D with a switch is $14.

 

[pattenp]

Just run conduit from garage subpanel to where it exits wall and place LB on outside and cap it off until you install wire to shed. Then just drop down from LB with conduit run to shed. This is provided that you run single conductors to the shed with no splices. No outdoor junction box needed unless you are thinking of the feed to the new detached garage coming from that same junction box. Yes, a small subpanel is needed for the shed. Also a subpanel can be fed from another subpanel.

 

[u2slow]

I'd get the basic 100A subpanel done hard and fast. Get that inspection closed.

If you go with surface conduit, there's no reason to open the walls and exhaustively 'future-proof'. Just install what you need when you need it.

EDIT: I prefer to feed buildings/sheds with cable instead of conduit. Then you bring the cable right to the panel inside, or transition to an LB and poke through the wall into the panel. No outdoor junction boxes needed.

 

[ard]

Just run conduit from garage subpanel to where it exits wall and place LB on outside and cap it off until you install wire to shed. Then just drop down from LB with conduit run to shed. This is provided that you run single conductors to the shed with no splices. No outdoor junction box needed unless you are thinking of the feed to the new detached garage coming from that same junction box. Yes, a small subpanel is needed for the shed. Also a subpanel can be fed from another subpanel.

Agree.

Only possible issue is if you cannot run the conduit with proper sweeps inside the walls.

and Id run PVC.

 

[Stuart in MN]

What state or country are you located? Codes vary all over the place.

For the record, the 2020 NEC is going to allow multiple branch circuits to a detached garage, but most locations in the US haven't adopted it yet.

 

[sparky 1971]

Just run conduit from garage subpanel to where it exits wall and place LB on outside and cap it off until you install wire to shed. Then just drop down from LB with conduit run to shed. This is provided that you run single conductors to the shed with no splices. No outdoor junction box needed unless you are thinking of the feed to the new detached garage coming from that same junction box. Yes, a small subpanel is needed for the shed. Also a subpanel can be fed from another subpanel.

Go this route. Or, set the subpanel on an outside wall. Then go out the back of it with two LB's. One for the shed, one for the other garage.