Project Update: Electric to Shed (image heavy)


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Old 09-25-17, 12:59 PM
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Project Update: Electric to Shed (image heavy)

Hi all!

Thanks for all the terrific advice on running power to/from my shed.

To recap, the project was to move my existing 30 amp 240V generator inlet (already wired to panel w/ lockout) to my shed so I can run the generator from there (I know, I have to thinking to do around ventilation/keeping it cool as a single window and two gable vents in my 10x12 shed may not be sufficient). The other goal was to route power to the shed to power the trickle charger.

Following the advice on this forum I did the following:
  • Dug min 20" deep trench--55' long
  • Ran two (one is simply there for future use) 1" Conduits
  • Pulled three #10 wires for H-H-N for generator
  • Pulled two #12 wires for H-N for incoming power to the shed
  • Pulled a single #12 ground wire as all the wire is in same conduit
  • Replaced Inlet with 4x4x2 weatherproof junction box
  • Backfilled the trench with 3" of sand, then a warning tape
  • Wires come in to shed to another 4x4x2 junction box.

I will have the inlet mounted beside the junction box and connect the outlet just below it, on a switch (I read that its required to have a shutoff where power enters shed?)

I hit a bit of a stumbling block... On the side of my house, I am trying to use exiting holes/wires coming from/to panel. That has left me with an issue on how to get 1/2 conduit from existing outlet to the newly installed (that I have to replace as I drilled a 3/4 hole for it) junction box...

I am thinking maybe I just need to replace the outlet to a duplex outlet style? Presuming I can make my own knockout on the back of it, I could line outlet up evenly with junction box? Thoughts?



I have one other kind of silly question... The wires (not shown in pic) are long enough, I could go from junction box directly to that outlet without making a connection in the junction box itself (ie, just pass through it). I suspect that is not allowed/somehow unsafe? Original plan is to use short wires from outlet to junction box and tie to the wires running to shed, using wire nuts. Just thought I'd ask if 'pass through' is safe/code compliant?

Here are some more pics from the project. WHOLE lotta work

Showing my non existing conduit bending skills



Put sand on top, then this to warn future diggers of electric


Where it runs along side of house-- still have to figure out where to apply straps and how to apply them when there is a .25-.5" gap between pipe and siding


Better view of trench


Conduit coming up at the shed


My nemesis


Backfilled!
 

Last edited by sirk98; 09-25-17 at 01:02 PM. Reason: corrected ground wire gauge
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Old 09-25-17, 03:15 PM
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The ground needs to be a #10.
 
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Old 09-25-17, 04:07 PM
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Clamps and backs are perfect for fastening conduit when there is a gap behind it. Places like depot and lowes carry them.

emerson/documents/commercial-residential/724320.pdf
 
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Old 09-25-17, 06:59 PM
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Wait. I was told that ground can be one size smaller.this is first time I am hearing it needs to be same size as inlet gage...?
 
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Old 09-25-17, 07:15 PM
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If shared ground wire is based on the wire size of the highest amp circuit. #10 is the same size as the hots.
 
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Last edited by ray2047; 09-25-17 at 07:35 PM.
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Old 09-25-17, 07:17 PM
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I'm sorry but you were told wrong. When running a shared ground with different sized conductors the ground is to be sized based on the largest sized conductors. A #10 30A circuit requires a #10 ground.
 
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Old 09-25-17, 07:38 PM
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In the other thread it looks like a #10 ground wire was mentioned several times. http://www.doityourself.com/forum/el...at-i-need.html
 
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Old 09-26-17, 06:19 AM
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Carbon monoxide danger!!!

Did everyone miss the part about running the generator INSIDE the shed? The OP mentions cooling and ventilation via window and gable vents but the danger of carbon monoxide buildup from the exhaust should be a primary safety concern. People have been killed by running generators, using charcoal grills, etc. in garages even with the doors fully open. The exhaust from the generator MUST be hard piped to a safe location outside the shed. If this is a portable generator, I doubt whether it is designed for such piping.
 
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Old 09-26-17, 06:20 AM
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argh! I literally got wires crossed in my head. I am REALLY glad I posted this.

Dumb question-- as I haven't terminated the wires yet, is it safe to just tape a 10 gauge to the end of the 12 and pull it through? (ie: wont damage other wire insulation?

This was a rookie mistake... So glad this was caught... I don't know what I was thinking. You are all correct-- I was supposed to go 10...

WRT to running it in shed: Shed is at far end of property. It is a portable generator. I was of the impression that CO danger is primarily for running in attached structures. This is over 50' from dwellings.

I may end up getting an exhaust made to pump it out the window...
 
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Old 09-26-17, 06:31 AM
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As long as your conduit is properly sized using the existing #12 to pull in a #10 is okay. You can buy some wire lube to make it easier to pull if it seems to have some resistance.
 
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Old 09-26-17, 06:46 AM
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thanks!

I'll replace the ground this weekend. THANK YOU FOR CORRECTING ME.

Any thoughts about hot to get the knockouts to line up between junction box and outlet? Is my idea to go duplex on the outlet the best approach?

Also, I had that question about whether I can just route the #12 wires through the junction box to the outlet, or if I should cut and connect to shorter wires from junction to outlet (current plan)?
 
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Old 09-26-17, 07:15 AM
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Carbon monoxide is colorless and odorless. It is also heavier than air so it settles to the bottom of the space. It will build up in the shed and when you go in there to turn the generator off or service it you could be overcome fatally before you realize what is happening. Do not rely on an exhaust fan in the window or any other method that only exhausts the space. Any exhaust must be directly piped from the generator exhaust to the outside. A portable generator may not be designed to operate properly with a piped exhaust due to pressure loss in the pipe, etc. Be safe!
 
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Old 09-26-17, 07:20 AM
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You can pass through the jbox with the #12's to the outlet box. Use a short piece of flex liquid tight conduit to connect the boxes.
 
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Old 09-26-17, 08:39 AM
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liquid tight conduit! thats the secret I am missing THANK YOU!!!!

have to figure out the fittings, but I am good to go

WRT CO and the generator. I will install a CO monitor in the shed and will not enter while alarm is going off... Thanks for the very important warning on CO. Worst case, I run it with doors open
 
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Old 09-26-17, 02:19 PM
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You may be able to pipe exhaust outside shed. Many have done it using 4" flex aluminum duct or galvanized duct.
Another option may be just making a door at the same height as the generator exhaust, and run generator right next to it. This still can cause CO build up, but much less possibility of deadly build up. Just make sure it is large enough so doesn't cause fire.
 
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Old 09-26-17, 03:09 PM
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There are Youtube videos showing using flexible automotive exhaust tubing and car mufflers. The exhaust tubing is to extend the exhaust outside and and the car muffler to reduce the sound. I don't know the pros and cons of doing that.

One example: https://www.youtube.com/watch?v=JjeJaqahP3E
 
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Old 09-27-17, 11:48 AM
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thanks! I'll look into those...
 
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Old 10-12-17, 10:23 AM
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One more update...

So, the liquidtight flexible conduit worked PERFECTLY.

One hiccup I hit: I know I need a shutoff switch in the shed-- the problem is that I installed PVC conduit too close to the front of the double gang box, so the switch wouldn't fit. So, I need to still add a switch somewhere (can I use the outdoor junction box currently in place above the outlet to house a switch? Its inside the shed--but there are no screws on it to accept a standard outlet/switch mounting screw...only has screw holes on the corners)... plan is to add another box somewhere, maybe near door...

In this pic, you can see the junction box (where LB enters the shed). To the left is the generator inlet. Below is the double gang box that I had wanted to house both switch and outlet, but only outlet fits (see above)



In this pic, you can see the horizontal run of conduit. We had to stop the underground conduit 4" from the house as there was a drain pipe I couldn't relocate. I think I can make regular PVC straps work... Any tips on how to keep my siding happy? I know that vinyl siding likes room to move... Concerned about all the screws I will be adding...


Finally, this is what the final connections look like on the side of the house. THANK YOU FOR THE LIQUID TIGHT TIP!
 
 

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