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New 30 Amp Shed Sub Panel underground electrical feed. - Should I use 10/3 UF-B or 10/2 UF-B and is

Post in 'DIY and General non-hearth advice' started by Don2222, Nov 26, 2011.

  1. oldspark

    oldspark Guest

    I dont think you were reading the links we were providing for you, sometimes its best to just farm things out. Have a good one and I dont like giving out electrical advice on a forum so I hope not to do this again.

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  2. Don2222

    Don2222 Minister of Fire

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    Please do not get me wrong oldspark. I want to thank you for pointing me in the right direction. I have been very busy and it takes time for all this to sink into my brain!

    This was a tough subject with a little confusion but now it is very clear from what you said. Thanks again and I appreciate your expert advise!
  3. Don2222

    Don2222 Minister of Fire

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    Hello oldspark

    Actually I would still really like to know if not under normal conditions, but under what conditions would create stray currents in a outbuilding sub panel with a bonded ground to neutral panel?
  4. woodgeek

    woodgeek Minister of Fire

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    If the neutral and ground are bonded at the service panel AND the sub panel, you don't have a ground in the shed. All return current in the neutral will flow through both the neutral and ground wire. Think about it--the only difference between the neutral and the ground in that rig is the color of the jacket.
  5. oldspark

    oldspark Guest

    I think it was touched on before, you create a parallel path for the returning current (neutral) even under normal conditions it can cause all sorts of weird things espicially if you are using metal conduit and have loose connections that can over heat, the fact of the matter is you may never have a problem wiring it that way but it is not worth the risk. I hope that is the answer you are looking for.
  6. nate379

    nate379 Guest

    You don't need 200 amp service to correct your breaker issue if all you need is more room in the panel. Yes you could get a larger panel but that is quite a bit of work to put in, all to just add a breaker.

    Look to see if your brand of panel carries "2 in 1" breakers, like this: http://www.amazon.com/Siemens-Q2020-120-Volt-Circuit-Breaker/dp/B00002N7KW

    You could combine 4 breaker spaces into 2 and then that would give you room for that 240v breaker for your sub panel. Not all panels allow this, you NEED to use the same brand breakers as the panel and also those breakers need to say it's ok on the model of your panel.
    This also applies with regular breakers as well.


    I do agree with the others please have a electrician take a look at your work, even if it's just a friend that is in the know.
  7. Battenkiller

    Battenkiller Minister of Fire

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    My lord, and I thought drying wood was complicated. :lol:

    I'll be a first time homeowner in a couple weeks. I think I'll let somebody else run the electric to my shed. :coolsmirk:
  8. oldspark

    oldspark Guest

    Information overload!
  9. Don2222

    Don2222 Minister of Fire

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    That's nice if you can afford it!

    So far I spent
    $142.00 for 95 feet of # 10-3 UF-B direct burial wire from Lowes
    $30.00 for 2 circuit load center and 2 20 amp breakers from Home Depot
    $8.50 for Main Load Center Panel Breaker
    $20.00 for gray PVC conduit and clamps to protect the AC wires on side of house and side of shed.
    $31.00 for 12-2 wire for shed outlets
    $6.00 for 1st shed outlet
    Total $237.50

    My own labor for digging a trench 2 - 3 feet deep and 27 Feet long. Code is minimum 18 inches deep.

    So if you can hire someone to do it for double that you would be doing very well!!

    Ok, electricians how much is the going rate for the 1st outlet in a shed like this that meets all code requirements??
  10. gpcollen1

    gpcollen1 Minister of Fire

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  11. Don2222

    Don2222 Minister of Fire

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    Hello oldspark

    Well thanks again, I looked up more detail and found a better explanation that I was looking for.
    Also thanks for being honest in saying that it may never happen in my small shed in the back yard since I did not use metal conduit.

    It seems Electro-Magnetic Interference (EMI) can cause these stray voltages you are refering to.

    It seems the major cause is:
    1. Older local electric utilities that do not distinguish between ground and neutral like in the old days!
    2. Old Motors in farm equipment with excessive leakage currents.

    Quote from link below
    1.
    "The electrical utilities do all of the wrong things relative to stray voltage. They consider ground to be the same as neutral and they connect the primary neutral and the secondary neutral together at their distribution transformers."
    2.
    "Farmers need to select electrical equipment, including lights, that will not generate excessive ground currents. Lighting ballast, electrical motors and auto-transformers are primary sources of leakage current even when they are UL approved and working correctly. All electrical equipment needs to be tested for leakage before it is installed. If the leakage currents is in excess of 1 milliamps (0.001 Amps), then the equipment should not be used. If you must use it, then special precautions must be taken in the electrical system design."

    See
    http://www.bassengineering.com/SV_Cause.htm
  12. Don2222

    Don2222 Minister of Fire

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    Hello Nate
    Thanks for your very good suggestion but I am 2-1 maxed out in the breakers. Just no more room. I do have new tri-plex 200 amp wires installed about a year ago from my house to the new telephone pole the Tel Co installed.
    So a 200 amp panel, 200 amp meter socket and new weather head and wires on the side of the house for $2000.00 is the only correct solution!
  13. burnham

    burnham Member

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    No, this has nothing to do with what oldspark was trying to warn you about. He was speaking of circulating currents. The link you posted is aimed more toward dairy farms where cows stand around in their own (conductive) piss all day while hooked to milking machines, and crap into a pit that has an auger in it....that's driven by an electric motor.

    The fact that the primary and secondary neutrals are probably bonded together at the transformer that feeds your house isn't a problem, the problem is you have just enough electrical knowledge to be dangerous.
  14. nate379

    nate379 Guest

    What do you think the cost would be if your burned your house down or killed someone?


  15. davmor

    davmor Member

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    That is a good book. I had one at one time, loaned it out, never got it back, lesson learned.
  16. Don2222

    Don2222 Minister of Fire

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    I agree that burning the house down is not worth it. I had one main breaker start burning up last summer and there was no more than 60 amps of loading. After the research I found that the springs in the breakers get weak and cause a loose connection and start burning up!!! Maybe those old fuses were safer??

    Anyway, this house was built in 1962 and I am still bringing things up to the new codes as soon as I can. There was a wood stove on the same flue as the boiler. In the old days the fire inspector said if the flue was 12 inches higher than the other flue that was OK!!! Well we know now it is not OK and I had a new SS chimney installed! Not cheap either!!

    So that is why I appreciate all this advise so even if I had someone else do the work I will know it is safe!!
  17. Don2222

    Don2222 Minister of Fire

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    I understand that was not what oldspark said, but I do not have metal conduit either so if you could please give an example that applies in my case of stray currents I really want to hear it??
    In the meantime I have to either find where to buy that equipment ground buss locally or order it on the internet.
  18. woodgeek

    woodgeek Minister of Fire

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    Ahem, not to speak for oldspark, but this is not about induced or stray current effects, its about you not having a ground in your shed. Of course, there are worse things than not having a ground (you could have installed two-prong out there), but the way you've done it, it looks like it has a ground (three prong) but it really doesn't!

    As a fault example, imagine a tool/appliance where the motor runs hot to neutral, and the metal case is tied to ground. Thirty years from now, under load, you get an open circuit in your neutral/ground line, due to corrosion and arcing caused by rainwater getting into that new 200 amp panel you are going to get (that silicone caulking was on sale after its expiration, and never did set up right). Now the case on the appliance is tied to hot, zotting the next owner of your home, George Jetson, as he stands in his crocs in a well grounded puddle during a rainstorm. Poor Jane. If you had not tied the ground and neutral wires together way back in 2012, however, the appliance loses juice, but George is protected by a still grounded case, even as he curses you and your now ancient DIY wiring and—vigorously shaking his fist—slips and drops the tool (with the still live hot) into the puddle he is standing in. What a schlemiel.

    At the same time, unknown to George, far above the rainclouds, a solar flare has caused an impressive aurora borealis display. The induced currents have troubled the young engineers at the local utility, knocking the new cold fusion plant offline temporarily. Of course, it has also induced 347 millivolts between the tool and the ground point in your/George's main breaker panel. George doesn't notice, and goes and takes a hot shower.
  19. oldspark

    oldspark Guest

    Stray currents can be one of the problems wireng it the way he did (look it up believe me I did and found it in many places) but there are all sorts of things that could happen down the road but the stray currents are the biggest concern with tieing the neutral and ground together on the load side (to the point of tripping devices not working correctly) and once again do not take my work for it look it up its every where . I will NOT wire in a sub panel (actually a non service panel) with out a ground rod period, do you plan on putting a ground rod in Don, just wire it according to code and correct the problems mentioned here and you will be fine.
  20. Don2222

    Don2222 Minister of Fire

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    Hello Woodgeek

    Sorry, You did not do your homework on this one. You may want to go to your nearest home depot and look at the outdoor 10-3 UF-B wire. It does have a bare ground wire and in my case it goes to the main panel buss and is grounded!!

    See pic below:

    Attached Files:

  21. Don2222

    Don2222 Minister of Fire

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    Hello OldSpark

    Thanks, I have been doing more research and stray currents can also be caused by long runs over one hundred feet simply by the voltage drop in the wiring. This is what I wanted people to tell me. However my run is only 95 feet so not much of a problem. Also by having an unbalanced sub panel. This means running 10-2 and installing one 20 amp circuit. Alot of devices going would cause stray currents on the neutral. However I ran 10-3 UF-B with 240 vac for 2 - 20 amp circuits in which I will balance between the outlets and lighting.

    So as you can tell I really appreciate the info and caution you guys are giving me.

    When I am out today I will be looking for that optional equipment ground buss that I can put in the subpanel that I can tie a ground rod to. It does not come with the load center I purchased.

    Also If you can find a really severe issue that pertains to my case that will cause stray currents, I would like to here it.
    Thanks again guys!
  22. woodgeek

    woodgeek Minister of Fire

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    Um, the picture is exactly what I have a beef with. I know you ran four wires, including the ground wire. The beef is that you tied that ground wire to the neutral on the sub-panel AND the main panel (IIRC). It is now not a ground--it is an uninsulated neutral wire! There has been some discussion here about whether the sub-panel ground should be tied via this conductor to the main panel ground, OR to a separate grounding rod near the shed. Seems to me like six of one, half a dozen of the other--depends ultimately on distance: short distance tie in the wire, long go with a rod. Neither option is what you have done.

    When we saw the ground tied to the neutral at the subpanel, (the picture above) all of our heads exploded, and we told you to not do that. You have been talking skeptically about stray currents since then, and do not appear to appreciate that you have wired things incorrectly.
    ewdudley likes this.
  23. Don2222

    Don2222 Minister of Fire

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    Understood WoodGeek.
    As I stated earlier I went out today and found the Optional Buss. See pic below
    Therefore it will be wired correctly very shortly.
    I am not a magician it just takes a little time.
    Thank-you

    Attached Files:

  24. woodgeek

    woodgeek Minister of Fire

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    capiche.
  25. jharkin

    jharkin Minister of Fire

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    deleted - redundant

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