# Wiring a shed, need advice.



## a_lost_shadow (Dec 18, 2011)

1,2, &4) Depends on whether you have a sub panel at the shed. I don't recall the requirements, so I'll leave this to others. However, I would recommend totalling up the wattage of everything that you want. That will give you an idea of how many circuits you need. Depending on the wattage, you might want to do fridge + lights on the first circuit, and everything else on the second.

3) Depends on the type of wire. Some wire can be directly buried, others require conduit. Additionally, the depth it needs to be placed depends on if there's conduit and what type. How much do you want to dig? Also if you lay conduit, it makes it much easier if you ever need to replace the line in the future.

5) You can always put a sub panel outside the shed, and branch off there. Again I'm not sure if you can run multiple circuits from the house to the shed without a sub panel out there. Am I correct that the shed is completely detached?

THHN - Single conductor wire for use in dry environments, must be in conduit
THWN -Single conductor wire for use in dry/damp/wet environments, must be in conduit 
UF - Multi-conductor cable (like NM-B aka Romex) that can be buried directly and used outdoors. Needs to be protected if subject to damage (i.e. running down the side of a building)
AWG - American Wire Gauge (a unit for measuring the size of a wire. Smaller #s equal larger wires in the #NN ranges. At 0 it flips over and x/0 is larger for larger values of x)

If you don't know what wire gauge is, than I'm extremely concerned that you're out of your league. If you just hadn't heard the acronym AWG, then you've just got a bunch of reading to do. I suggest picking up a few DIY books on electrical wiring. While subpanel wiring is within the DIY realm, it shouldn't be your first introduction to working with 120/240V.

There are other questions that will need to be answered:
- How far is the shed from the house?
- Do you have to go through the house to get to the shed, or is the meter on the same side of the house as the shed?


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## hgbpro (Feb 2, 2012)

shadow,

thanks for the reply. I do have knowledge of wire gauges. Just had never heard the acronym AWG. thank you for the low down on all the acronyms. The shed sits 25 feet from the house and is completely detached. theindoor home breaker panel is on the same side of the house as the shed, directly across 25ft. the houses outside panel is on the far side of the house from the shed. it is more convienent for me to use my indoor panel on the house as my source. After your suggestion, i will use conduit. Will the grey PVC type suffice? I will be dropping down from my breaker panel into my crawl space and then through the wall of the crawl space to the exterior of the house, then I will run the conduit down the rest of the foundation into the ground and across the yard to the shed. Is 18" deep enough if using the conduit? Thanks for the help


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## TarheelTerp (Jan 6, 2009)

Cutting to the chase...
it's just as much bother (and expense) to pull one set of larger wires vs 2or more sets of smaller.
So? Pull bigger wire. I'll suggest using 6/3UF cable or wire in PVC conduit (have to trench either way).

And yeah, set a small sub panel box out there.
Have (almost) as many circuits as you like.


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## zappa (Nov 25, 2011)

hgbpro said:


> Will the grey PVC type suffice? Yes, it needs to be rated for electrical which the grey normally is.
> 
> Is 18" deep enough if using the conduit? It depends on your area and frost depth. I would check with your local codes and see what they suggest.


.....


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## Stubbie (Jan 7, 2007)

Table 300.5 NEC


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## PlumbDumb (Jan 30, 2012)

Well said Tarheel.

Pulling 6/3 through condo into a nice 50amp sub panel will give you everything you could need. Id like to offer some advice, as a plumber by trade i just completed a similar project for my uncle. So i have been binging on electrical books, forums, and distracting electricians on the job with hand drawn diagrams to make sure I didn't become "that guy".

If you run 6/3 through conduit, your 50amp sub panel will have: 120v, 240v, (the extra conductor brings a second phase of 120v to the panel, which a double pole breaker can send both phases to a future 240v appliance like an air compressor/welder/heater), neutral and ground protection. This also distributes the load of your entire shed over the 2 120v phases, and not a single leg.

Refrigerators should really be on their own dedicated 20 amp breaker wired in 12/2.

Your lighting load is not too bad, so keep all your lights on one 15amp breaker. This way you eliminate switches, boxes, and junctions: when you want light, just flip the breaker. You can even run 14/2 for your lights (at least in my area) but sometimes its easier to just use 12/2 for everything. If you use 14/2, you must only use a 15amp breaker. 15a breaker protects 14 gauge, 20a protects 12.

Chop saws/120v air compressors and a bunch of other common tools run at the higher end of a 20a breaker, especially when they first start up. I say pimp your quad box: Put each of the 2 outlets on their own 20a breakers. This will give you a huge advantage: Chop saw on one breaker, air compressor on the other, then use the remaining 2 sockets to plug in your chargers/low current stuff and you can get every last bit of 40amps out of one quad box, as opposed to 20 amps across all 4 sockets on one breaker. Installing 2 GFCI outlets could save your life one day.

20amp-fridge-12/2 15amp-lighting-14/2 20amp-1st outlet-12/2 20amp-2nd outlet-12/2


Stupid plumber, that's 75amps of breakers! Chances are 3 of your heaviest tools and the fridge will not all fire up at the same time as you hit the lights. All of your stuff should play nice on the 50amp, double pole breaker protecting your 6/3 feed. If you wanted to really knock it out of the park, make it a 100amp sub panel: just pull 4/3 and connect it to the main panel with a 100amp breaker. Just make sure the panel is rated for whichever amperage you pick.

As of right now you need 4 breakers for 4 circuits in your shed. So grab a 50amp sub panel with space for at least 6 breakers: the 4 now and at least one future 240v or 2 future 120v circuits.


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## Julius793 (Dec 13, 2011)

Remember there must be a main disconnect at the shed


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## Julius793 (Dec 13, 2011)

PlumbDumb said:


> Well said Tarheel.
> 
> 
> If you run 6/4 through conduit, your 50amp sub panel will have: 120v, 240v, (the extra conductor brings a second phase of 120v to the panel, which a double pole breaker can send both phases to a future 240v appliance like an air compressor/welder/heater), neutral and ground protection. This also distributes the load of your entire shed over the 2 120v phases, and not a single leg.
> ...


Firstly a typical fridge doesn't need a 20 and will not trip on start up if it's a 15. Second when you say 12-3 that means 2 hots one neutral and ground. 12-2 is on hot one neutral and ground. My point being ground is not counted In the name.


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## PlumbDumb (Jan 30, 2012)

thanks got my nomenclature messed up


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## frenchelectrican (Apr 12, 2006)

Plumbdumb.,

There is one item you will have to remember that with most modern code if you ever run MWBC ( Multi Wire Branch Circuit ) you will need two pole breaker or with handle tier ( I am not too crazy with this part but it is legit ) 

A Lost Shadow .,

In case you look for the THHN / THWN conductor they genrally are dual rated for both dry and wet location purpose.

Merci,
Marc


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## PlumbDumb (Jan 30, 2012)

When i installed my sub panel i used an MLO sub panel protected by a double pole breaker at the main panel. Is that illegal?


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## Julius793 (Dec 13, 2011)

PlumbDumb said:


> When i installed my sub panel i used an MLO sub panel protected by a double pole breaker at the main panel. Is that illegal?


If it's in a separate structure than it must have a main disconnect.


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## zappa (Nov 25, 2011)

Julius793 said:


> If it's in a separate structure than it's not per code.


Huh? :blink:

Did he PM you with the number of breakers in his panel?


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## Julius793 (Dec 13, 2011)

zappa said:


> Huh? :blink:
> 
> Did he PM you with the number of breakers in his panel?


Your right I redid my post.


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## hgbpro (Feb 2, 2012)

thanks everyone!

dumbplumb, i like the details you gave.:thumbsup:

Is this the type of 6-3 i will need?
http://www.ebay.com/itm/UF-B-6-3-Un...095?pt=LH_DefaultDomain_0&hash=item2ea92d6ccf

Also, what size and how many breakers will be added to my current home panel.

I completely understand how to wire the outlets & switches, but if someone could expand or even provide a diagram of how to wire the 6/3 on the home panel end, and at the shed on a 50amp sub panel. my home panel is a cutler hammer.


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## zappa (Nov 25, 2011)

Julius793 said:


> Your right I redid my post.


I think you need to edit again. Remember the number six (6)?


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## Julius793 (Dec 13, 2011)

zappa said:


> I think you need to edit again. Remember the number six (6)?


Yes up to six breakers is considered a main. I guess I forget who I'm dealing with.


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## jbfan (Jul 1, 2004)

You still need a disconnecting means for the detached shed, via a switch, or disconnect mounted before the panel.


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## Jim Port (Sep 21, 2007)

I don't think the OP even needs a 10-3 to the shed based on the proposed loads.


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## zappa (Nov 25, 2011)

jbfan said:


> You still need a disconnecting means for the detached shed, via a switch, or disconnect mounted before the panel.


Sorry Julius, I should have kept my trap shut as I didn't know this.

jbfan.....where did the 6 throw rule come from if a disconnect near the panel is still needed?


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## Julius793 (Dec 13, 2011)

zappa said:


> Sorry Julius, I should have kept my trap shut as I didn't know this.
> 
> jbfan.....where did the 6 throw rule come from if a disconnect near the panel is still needed?


Nothing to apologize about. The way I remember 225.32 and 230.71 you are correct.


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## rrolleston (Oct 17, 2011)

You could always run the wire in conduit and if you decide to upgrade you can just pull larger wires. Use at least one inch conduit and you will be ok. I can't remember how many times someone has refused to go larger or pay enough to have the wire in conduit. Then a couple years later find out they outgrow it.

Also don't forget to use expansion couplings whenever you go from the building into the ground.


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