Power for office shed

[ckucia]

So I've been building a 8x16 office shed in my garage. Basically made it so it can be broken down in panels and reassembled on site. I'm just about done and we settled on a spot for it in the back yard.

Unfortunately, that spot is 100' from the back corner of my garage. The breaker panel in the garage is on the other side of the building - another 48 feet away.

So throwing in the extra length to route, I'm probably looking at 175' run from panel to panel.

I definitely want to use conduit and run a second conduit for Ethernet and phone.

I'm also leaning towards putting an outside light with a 3-way switch with one switch in the garage by the breaker panel and the other at the shed end (my wife likes the dark, but I may need to run out there in the middle of the night if I'm on call).

I'm going to be running a small room air conditioner, a laptop, 3 LCD monitors, a small fridge and some LED lighting. Maybe a coffee pot.

My first inclination was to run #4 THHN off a 60amp double breaker, but that really seems like overkill. This is never going to need more power than it does with me, and I'm running all this equipment now (except the A/C) on a 15 amp circuit in my living room. I think if I had two 20-amp circuits, one for the A/C and one for the equipment and lighting, I'd be fine (heating with propane, BTW).

How would you guys approach this in terms of wire size for both the main power and the three way switch circuit? What size conduit would be appropriate? Can I run the 3-way wiring and the shed wiring in the same conduit? Is there any advantage to powering the light off the garage wiring instead of the shed wiring or vice-versa?

 

[dscheidt]

The 3-way for the light needs to be powered from the shed, so that killing the feed for the shed in the garage kills it (building is only allowed a single circuit).

The work of digging 100' of trench outweighs the cost of wire, breakers, etc. I'd run 4 AWG aluminum XHHW2, from a 60A breaker, and put a small (6 or 8 space) panel in the shed. You're probably right about the load, but you might want a better AC in the future. If you never use any of the capacity, you will never think "Gee, I'm glad I saved that $300" past the first couple months. If you need it, and it's not there, you will curse yourself to no end. If it's there, you'll think "gee, wasn't I clever?". You can fit three 4AWG xhhw-2 and a 6 or 8 gauge ground in a 1" pvc conduit, but bigger would be easier to pull. 3/4" should be enough for your other conduit; that's enough for 4 cat6 cables or 6ish cat5. (pull a spare, and leave a pull string)

 

[mike93lx]

I agree with dscheidt. Run aluminum wire for the feeder, for sure. It will save a bunch of money and really have no disadvantage.

I'd go at least #4xhhw for the feed. It's cheap and easy to work with. For the 3-way switch, #14 thwn would easily cover a light bulb at that distance.

A small panel around 8 circuits will be cheap as well.

Consider fiber for networking. It eliminates any surge carrying potential of copper.

Don't forget your two ground rods

 

[ckucia]

Thanks guys. We're very rural and my only source for electrical stuff is Lowes an hour away. I need to check in person, but they don't carry #4 aluminum in my store, at least according to the online site. Any online wiring places recommended? Cost to ship aluminum shouldn't be that bad...

Mike, your comment about the fiber intrigued me. I've had fiber at places I worked, but I've never run it myself. Despite doing IT for several decades, I realized I don't know squat about running fiber.

I need to get this up (I already started the job that created the need for this space), so I'm leaning towards just putting in cat6 for now and running the fiber cable until I can get the equipment I need to terminate it properly (I already have all the cat6 stuff). Do you still need special equipment to cut/polish the ends, or can I just get a pre-terminated 200' or so length and coil up the excess and deal with the connections on both ends later? My switches are all straight Ethernet so at a minimum I suspect I need those replaced unless there's some sort of converter I can put on both ends to convert the fiber signal to cat6.

 

[mike93lx]

Wireandcableyourway.com

For the fiber, buy preterminated lengths with pulling loops. Yes, you would need a new switch/converter. There are some good threads on here regarding fiber. I'm certainly no expert on the subject

 

[dcg9381]

Personally, I'd treat this like an RV. I'd put a Siemens Talon panel (Amazon ~$150) out there in the yard (or on the building) and let it do everything you need. It's already got 3 breakers in it (20A GFCI, 30A @ 120V, 50A @240V). Rather than run 3-way lighting, you're going to do internet, so you can do any number of "smart switches" and turn the lights on by smart phone or voice (google/Alexa/ETC). You won't need much power out there, somewhere between 60A and 90A on that panel is way more than you'll need... The above wire vendor has been great for me also... (Wireandcableyourway)

2" conduit would be fine.
3/4" conduit for data (unless doing fiber, you may need bigger)

Like you, I'm in IT but have never done fiber. Fiber is better because it's not going to be sensitive to induction from (nearby) lightening. Monoprice offers pre-cut / pre-terminated fiber in 150' lengths (50M). I've never used it or the converters at the ends. I ran CAT6 shielded... Just do two pulls in case you need a spare, but again, I agree that fiber is probably the better solution.

 

[engineer2]

Plenty of info on shed wiring in the Electrical Section.

I followed some advice here and buried 1-1/2" PVC next to my RMC electrical conduit. I use it for an air hose, but plenty of room for Cat-6 if I need it in the future. For the elbows I used the long-sweep ones for PVC electrical conduit.

An air hammer works well for driving in grounding rods.

 

[Bert_]

Personally, I'd treat this like an RV. I'd put a Siemens Talon panel (Amazon ~$150) out there in the yard (or on the building) and let it do everything you need. It's already got 3 breakers in it (20A GFCI, 30A @ 120V, 50A @240V).

So one circuit that is useable as is.... It's not what I would recommend.

#6-#4 aluminum and a 4-8 space panel. Keeps it simple and cheap.

 

[dcg9381]

3 circuits usable on that panel.. (comes with outlets and breakers). 4 additional slots.

 

[Bert_]

3 circuits usable on that panel.. (comes with outlets and breakers). 4 additional slots.

2 outlets he would have no use for and 1 120v outlet he can use.

 

[ckucia]

I have the wire now. I'm ready to start picking up conduit and digging the trench. I planned on using 2" PVC.

Problem is, the breaker panel I'm feeding off is about 8' from the back of the garage, then I have to go the 48' length of the garage, turn 90 degrees and head straight for the office shed - another 100' then come back up out of the ground. So that's 5 90degree sweeps and then an LB at the end to penetrate the shed. I don't think that's within code (especially if you include the LB).

So I thought I'll just put a pullbox at the corner of the garage where it heads the last 100' to the shed. Just come up out of the ground with both conduit runs, do a u-bend in a box and then go back. That's 4 bends on one run and two (3 with the LB) on the other. However, it appears I'd need at least a 14" box (6X the conduit size +1) with 2" conduit and the largest I can find is 12x12. Using 4awg AL cable BTW.

I can't make a straight shot to the shed from the corner of the garage just using the bend of the conduit to follow the path to where the breaker panel is because our firepit is smack dab in line and I don't want to have to dig that up and go deep enough to avoid the danger of heating the conduit. I prefer conduit to take direct paths so finding it later (or not finding it with an excavator) is easy. About the only solution I can think of is to use two 45s in the path from the shed to the garage and sorta offset the run so the end of the second 45 lines up with the run along the garage on a path to the breaker box. I still go over 360 if I include the LB at the end.

This seems less easy than it should be. I'm not doing anything crazy here. Am I missing something?

 

[PCustoms]

2" PVC seems huge for #4 wire.....

 

[Bert_]

I have the wire now. I'm ready to start picking up conduit and digging the trench. I planned on using 2" PVC.

Problem is, the breaker panel I'm feeding off is about 8' from the back of the garage, then I have to go the 48' length of the garage, turn 90 degrees and head straight for the office shed - another 100' then come back up out of the ground. So that's 5 90degree sweeps and then an LB at the end to penetrate the shed. I don't think that's within code (especially if you include the LB).

So I thought I'll just put a pullbox at the corner of the garage where it heads the last 100' to the shed. Just come up out of the ground with both conduit runs, do a u-bend in a box and then go back. That's 4 bends on one run and two (3 with the LB) on the other. However, it appears I'd need at least a 14" box (6X the conduit size +1) with 2" conduit and the largest I can find is 12x12. Using 4awg AL cable BTW.

I can't make a straight shot to the shed from the corner of the garage just using the bend of the conduit to follow the path to where the breaker panel is because our firepit is smack dab in line and I don't want to have to dig that up and go deep enough to avoid the danger of heating the conduit. I prefer conduit to take direct paths so finding it later (or not finding it with an excavator) is easy. About the only solution I can think of is to use two 45s in the path from the shed to the garage and sorta offset the run so the end of the second 45 lines up with the run along the garage on a path to the breaker box. I still go over 360 if I include the LB at the end.

This seems less easy than it should be. I'm not doing anything crazy here. Am I missing something?

LB's are pull points and don't count towards your 360*

Maybe put up a drawing or something, I'm not seeing how you come up with (5) 90's

 

[theoldwizard1]

The simple solution to the three way is use a wireless three way switch !

Fiber is not worth the cost. Use Cat 6 cable. Ethernet is "isolated" at each end. There are no direct electrical connections.

 

[mike93lx]

The simple solution to the three way is use a wireless three way switch !

Fiber is not worth the cost. Use Cat 6 cable. Ethernet is "isolated" at each end. There are no direct electrical connections.

Please explain how ethernet has no direct connections

 

[dscheidt]

Please explain how ethernet has no direct connections

There's a transformer coupling, and no direct current path from one endpoint, over the twisted pair cable, to the other endpoint.
This is required because ethernet has long cables (as long as 100 m per spec, and in practice, even longer), and it's not uncommon to ind that the ground reference at one end of the cable is not the same as the other end.

I forget what the isolation voltage is (1000V? 2000?, something like that), but it's not enough for isolation from lightning protection. It's high enough it's good enough most of the time, though. Around here, I'd have no problems running ethernet to a shed. Somewhere with more lightning, not so much.

 

[ckucia]

Well, I have most of my conduit and I have about 2/3 of the trench dug. I'm going with 1-1/2 for the power.
I priced the THHN wire for running a 3 way switch and, at least at Lowes, it's pretty pricey. Willt cost almost $300 for the wire but I'd have extra.

So I thought I'd look into the smart switches as suggested above. Is anyone aware of a simple primer on a very basic smart switch setup? Google has gotten to be sucktackular in trying to find info. Most of what I find is converting existing 3way switches to smart switches. I don't need Alexa or Google control, or integration into some Borg home controller. Just two switches that control one hardwired light. Seems like a simple thing, but I'll be darned if I can find solid info on what switches will work in my situation and how to configure them. And a lot of those things aren't exactly inexpensive. I'm about to throw in the towel and just buy the wire and do it the old fashioned way as I already have switches in my box of extra electrical stuff.

 

[wes73]

One thought on the 3way switch/smart switch...If you have a LiftMaster Garage door opener that is wifi (MyQ) enabled, check into their smart switch. I have 4 of them. 2 for outside garage lights, 1 for pool lights and 1 for outside house lights. The one for the house is in the house 120 feet from the garage. works great. Just saying you may have part of what is needed.

 

[ckucia]

I found a place online with the wire at a decent price so I'm just going to wire it the traditional way. No complications and dead reliable.