Hello,
Was looking to add a sub panel into a shed. Length of the run is about 70' max. My intentions were to run a 2p30 from the main panel to a sub panel inside the shed. Was going to run 10/3 romex and junction it outside with 10/3 UF to the subpanel. My understanding is I would need to add 2 more grounding rods w/ #6 copper outside the shed. Does this circuit need to be GFCI protected from the main panel? Also with the MLO sub panel inside the shed with the potentiality of being locked, is an outdoor disconnect required outside the shed? If so would that be outside the house where I had planned to junction or on the surface of the shed before entering to the sub panel?

 

Overall the plan sounds good. The UF-B should be buried at 24" depth with conduit sleeves on the risers in and out of the trench. The panel feeder does not need GFCI protection, but all 120V receptacles in or on the shed do need GFCI protection. There are many ways this can be accomplished such as GFCI receptacles or breakers. Yes the subpanel needs at least one ground rod bonded to the subpanel ground bus with #6 copper. An outside disconnect is not strictly required, but code does require a disconnect "at first point of entry" of the building. An easy way to meet this code is to use an $8 air conditioner style pullout disconnect on the building exterior. This meets the disconnect requirement and also gives you an easy spot to switch from the UF to NM or conduit depending on how the interior of your shed will be wired.

 

Just run UF from panel to panel and use a main breaker panel in the shed. No splicing and the disconnect is taken care of by the main breaker in the subpanel.

 

No re4aso to use a MLO. Normally we recommend a main breaker panel. As Pat pointed out no need to add a separate disconnect. Also you will often find a 100 amp MB kit to be cheaper especially since it will include most if not all the branch circuit breakers you will need. MLO you will need to buy breaker raising the cost. MB panel you only need to buy a ground bar.No. Should you be locked out you can use the breaker at the house to disconnect.

Why do you need a panel at the shed. If no 240v loads a 20 amp multi wire circuit could provide you with two 120v/20a circuits, no panel needed.

 

Would doing this still require grounding rods for the shed? I am tossing around the idea of adding a single 120v outlet to my shed that's about 3 feet from my garage. It'd be nice to have a plug in there. I park my lawn tractor in there and every winter pull the battery to put on a battery tender in the garage. I'd also like to make a little more room in the garage and put my air compressor in there. Just 120v compressor I use to fill tires and such. Takes up a lot of wall space for something I only use a few times a year. It's a detached garage with it's own 100 amp service/meter (not a sub panel from the house). The garage is grounded per code, but the shed is not attached to it. It's a wooden shed/wooden floor sitting on those concrete deck blocks. Bad idea?

I already have the wiring out the side of the garage into a junction box. 12/2 on a 20 amp GFI breaker. This was power to the shed, but when i bought the house, it was a hack job. 12/2 romex through the walls hanging in the breeze. To get it to pass inspection, the sellers removed all power to the shed. The electrician they hired was nice enough to add an outdoor junction box so conduit could be run from it down the wall and underground to the shed.

 

A MWBC does not need a grounding system installed. It is considered a single circuit.

 

For a MWBC you need 12-3. GFCI is optional. Breaker must be two single pole handle tied 20a/120v breakers or one double pole 20a/240v breaker. A simple DPST toggle switch in a 4x4 box at the shed can serve as the code required disconnect. Switch example: http://www.homedepot.com/p/Leviton-2...-2WS/202027029

 

Thanks guys, I just talked to an electrician and he's coming out next week to give me a quote. He pretty much said that same as you guys. Even if I only want 1 circuit, it wont be much more to run 12-3 for future use. It'll already be in the wall and underground, so if I do decide to add lights or something else, it'll be much cheaper down the road. I am insulating and sheet rocking the garage, so it only makes sense to change out that 12-2 for 12-3 now while it's easily accessible. The breaker panel has 5 unused spaces, plenty of room to add circuits.

On the same note, the garage has an upstairs with only 1 circuit for lights, before I close up the walls downstairs, he's going to run 2 more circuits and give us some outlets up there. The wife has always want to set up an exercise room up there, but no power for her treadmill or a window A/C unit.

 

If you go to 10-3 you will have three options. One 120v/20 amp circuit now or later one 120v/20a MWBC giving you two 120v/20a circuits or later a 240 volt capable subpanel supplied by a 30 amp breaker.