Outbuilding Wiring & Code Advice Needed

[DC73]

Shipping Container Wiring & Code Advice Needed

I've ordered a shipping container to use as a storage shed in my backyard. I'll need to get a little power out to the container. Plan to have one outdoor single bulb light fixture w/ LED bulb, one or two indoor single bulb light fixtures again w/ LED bulbs, and one or two duplex outlets (not likely to be used for much until I transition to battery powered lawn equipment).

The closest place to get power is my existing workshop. I'll be running wire underground to the container. The run will be no more than 40' if I can do what I'm thinking.

The AC disconnect on the workshop is nearby and is one of these Square D units: https://www.homedepot.com/p/Square-...kW-Non-Fuse-AC-Disconnect-QO200TRCP/202353314

The small AC compressor requires a 15A breaker which is in the main breaker panel inside the workshop.

The wire from the panel to the AC disconnect is 10-3 w/gnd so I have a capped off neutral in the AC disconnect.

Questions:

1) Can I replace the existing 15A AC breaker with a 30A breaker, then replace the existing AC disconnect with some type of two space panel where one space gets the 15A breaker for the AC compressor and the other space gets a 15A breaker for the circuit to the storage building?

2) If this is possible, can you recommend a panel to replace the AC disconnect? Would a spa type panel work?

3) Would prefer to run the wire in conduit. Is plastic okay?

4) How deep does wire need to be buried? Is warning tape required?

5) Best wire to use? UF?

6) Can I take the wire that will run to the storage building directly to a junction box on the inside and then branch from there to switches, outlets and fixtures? Or do I need to make some type of transition on the outside of the building?

Thanks much,

Appreciate the help.

DC

 

[DC73]

Bump

 

[AntonLargiader]

When you say you capped off the neutral, I infer that the AC disconnect is 240V 15A. So you want to replace that with a small outdoor subpanel with a 15A 240V breaker and a 120V 20A breaker for your container shed. If the breaker meets the requirements for a disconnect, I'd think that would be an option.

Is it that hard to pull power straight from the existing panel to the shed? Is the difficulty just transitioning rom indoor to outdoor?

For the feeder, you could direct-bury UF-b or pull THWN through PVC conduit. Pulling UF through conduit is allowed but it is a pain: it's a flat, stiff cable that doesn't like to bend certain ways, and it's a pain to strip.

You should have a switch as a means of disconnect at the container/shed that interrupts the whole circuit.

 

[DC73]

When you say you capped off the neutral, I infer that the AC disconnect is 240V 15A. So you want to replace that with a small outdoor subpanel with a 15A 240V breaker and a 120V 20A breaker for your container shed. If the breaker meets the requirements for a disconnect, I'd think that would be an option.

Is it that hard to pull power straight from the existing panel to the shed? Is the difficulty just transitioning rom indoor to outdoor?

For the feeder, you could direct-bury UF-b or pull THWN through PVC conduit. Pulling UF through conduit is allowed but it is a pain: it's a flat, stiff cable that doesn't like to bend certain ways, and it's a pain to strip.

You should have a switch as a means of disconnect at the container/shed that interrupts the whole circuit.

The 15A AC breaker is in the main breaker panel of the workshop. The AC disconnect (I linked to it in the first post) is rated at 60A. It was a fairly short run to the disconnect and I happened to have a spare piece of 10-3 w/Gnd handy so that's how I ended up with a now convenient neutral pulled into the disconnect.

Yes, it's going to be a major pain to get power from the existing panel. I have 3 options and none of them are good. Open up walls to get power to the outside wall, surface mount conduit along walls where it would be inconvenient to surface mount, or use a spare conduit I ran into the attic space. The attic is very low profile so not much room to work above the panel and, due to a hip roof, even less where I would need to run the wire to exit the building.

Since I don't need much power to the container and already have 10-3 w/Gnd to the current AC disconnect, I thought that would be the easiest place to tap.

I know I can make it work electrically but I want to stay code compliant.

I found this 2 space panel that I think will work: https://www.homedepot.com/p/Square-D-Homeline-70-Amp-2-Space-4-Circuit-Outdoor-Main-Lug-Load-Center-HOM24L70RBCP/100194428

Thanks for the feedback.

DC

 

[AntonLargiader]

With a 2-space panel you'd need a quad tandem breaker to give you 15A@240 and 20A@120, like this but I don't know if you can get them for 15A@240. What does your AC unit say for Max breaker?

 

[DC73]

With a 2-space panel you'd need a quad tandem breaker to give you 15A@240 and 20A@120, like this but I don't know if you can get them for 15A@240. What does your AC unit say for Max breaker?

Whoops. I went brain dead and forgot about the 240V AC breaker needing two spaces. The panel I linked won't work. The max is 15A for the AC unit.

DC

 

[DC73]

While doing some research on this, I came across this blurb regarding burial of branch circuits (source said this was from the 1989 NEC):

"Residential branch circuits rated 120 volts or less with GFCI protection and maximum overcurrent protection of 20 amperes" has a minimum cover requirement of 12" in a landscaped/lawn area.

It also said the minimum depth could be reduced to 6" with 2" of concrete cover.

Is this accurate?

There was no mention of whether or not this applied to direct burial cable or just cable in conduit. Clarification?

Would the cover include gravel? This would be in a xeriscaped area where there is 2" of gravel on top of the soil.

DC

 

[dcg9381]

Re: Shipping Container Wiring & Code Advice Needed

1) Can I replace the existing 15A AC breaker with a 30A breaker, then replace the existing AC disconnect with some type of two space panel where one space gets the 15A breaker for the AC compressor and the other space gets a 15A breaker for the circuit to the storage building?

Someone correct me, but this might be my plan:

1) Replace your AC disconnect with an exterior rated sub-panel (I like the Siemens TL137US because it has outlets, breakers, and GFCI, and 4 spare spots but your feed is a bit small).

2) You've got 10/3, so your breaker goes from 15A to 30A for feeding the sub panel.

3) I believe code says that AC needs a "readily accessible" disconnect and an exterior breaker in this sub panel, nearby the AC, labelled, would suffice. It needs to be 15A like the original. People don't typically use breakers as they are more expensive than a disconnect, but it appears that breakers are allowed.

4) Feed your building shipping container, underground conduit (or appropriate ground-contact wire) from the sub-panel.

Likely all of this might be accomplished with existing wiring, depending on how much slack you've got..

 

[AntonLargiader]

I think that's pretty much what he was thinking in post #4, but he needed more slots in the panel.

 

[DC73]

I like the Siemens TL137US . . .

Likely all of this might be accomplished with existing wiring, depending on how much slack you've got..

Thanks for the input. That panel is bit much for my needs. Having enough slack might be the issue.

I think that's pretty much what he was thinking in post #4, but he needed more slots in the panel.

Yep. My existing workshop panel is Square D. Prefer to just move the 15A breaker to a new Square D panel. I've found this 4 space panel which should work: https://www.homedepot.com/p/Square-D-Homeline-125-Amp-4-Space-8-Circuit-Outdoor-Main-Lug-Load-Center-with-Ground-Bar-HOM48L125GRB/100196368

My problem now is that I'm not sure I have enough slack for this panel to replace the existing panel.

One thought was to just replace the AC disconnect with some type of exterior junction box and connect wire from there to the new panel.

Another thought that I would have to run by the code experts: Could I use wire nuts inside the existing AC disconnect, run a pigtail inside for the existing disconnect switch, and run a new set of wires to a new small panel mounted next to the AC disconnect?

If I could do this, I could keep the AC disconnect for the AC and just mount the two space panel I linked in post #4 for the storage building.

Appreciate the help.

DC