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    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #1

    Jan 28, 2008, 07:52 PM
    200 amp main feeding 200 amp sub-panel
    The utility spotter recommendeds the corner of my house as the location for a 200 amp aerial service entrance/meter base. My county requires a shut-off switch with the meter base, so a combination meterbase and load center is the standard here.

    I'm okay with her recommended SE location, but long term I'd like to be able to run new branch circuits easily without opening up the stucco. Due to the low angle of my single story hip roof, that won't be possible from the SE location. So I want to install a sub-panel in the garage where most of the branch circuits will originate. The top of the garage wall offers a straight shot into the attic (single story) so it should be very easy to work with in the future.

    I read in this forum that a 200 amp panel can't handle the 200 amp breaker needed to feed a 200 amp sub-panel. What do you guys recommend? What's the best way to get 200 amps to my garage sub-panel?

    Before reading that post earlier, I'd planned on ordering this equipment:
    * GE 200 Amp Outdoor Meter Socket Main Breaker Load Ctr 4-8
    OR
    * GE 200A Met/Sock 20-40 load center and meter panel
    AND
    * GE 200A 40-40 Subpanel
    * GE 200A 2 pole circuit breaker

    So what do the experts recommend? (btw, I can't afford a 400 amp SE panel =)
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #2

    Jan 29, 2008, 05:29 AM
    The simplest thing to do would be to just have a 200 amp main breaker at the meter, which will then feed a 200 amp branch circuit "sub" panel in the garage.

    I get that you want a few circuits at the meter location, and most at the 200 amp panel in the garage. This can be difficult to do, as you will not find a 200 amp panel that will accept a 200 amp branch breaker to feed the "sub" panel.

    What you can try is to find a meter with a 200 amp main breaker and also has a panel with a few circuit spaces, and 200 amp subfeed lugs that could be used to extend the 200 amp feed.

    Please note the link showing the 200 amp breaker, the picture is not the actual breaker, see the note at the bottom that the actual breaker is four poles, bascially two 100 amp breakers attached to each other and with jumpers to connect the two 100 amp breakers so that each line is then 200 amp rated. You cannot use that 200 amp 4 pole breaker as a branch breaker, it is only used as a Main breaker in some the GE panelboards.

    Read the specs for any GE panel, you will see that the max branch breaker will be 125 amp allowed.

    Ge does offer a subfeed lug kit #THLK2200:

    http://www.geindustrial.com/catalog/buylog/01_BL.pdf#search='thlk2200'

    http://www.geindustrial.com/publibrary/checkout/Catalogs%20and%20Buyers%20Guides%7COEM-LOADCENTER%7Cgeneric#search='thlk2200'

    That can be installed into certain panels.

    I believe this part will help you do what you want.

    Before you design this service and purchase any equipment, be sure to check with your power utility for their allowed metering equipment, not all utilities accept all meters. Some want ringed, and some want ringless, for example
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #3

    Mar 18, 2009, 04:19 PM
    Boy it was over a year ago that I posted this question, but the project is still ongoing and I need some help please! :)

    I hired a retired electrician to install my main 200 main panel and meter (plan to do the rest myself). I went with the equipment mentioned above. That is, I have #THLK2200 ready to feed the sub-panel.

    I called the electrician who installed the main to get his recommendation on wiring gauge. When I told him that the sub would be a 200 amp though, he didn't think that would be to code, and that the largest sub-panel I would be allowed is 125. He also thought that a pass-through at the main lug wouldn't be acceptable, and that it would need to be a breaker instead.

    Personally, I don't see the problem with the set 200amp lug setup. If the sub tries to pull more wattage than the system has available, won't the main breaker on the main panel trip? This electrician is a good guy, but he just moved here (Los Angeles County) from several counties away and he seems a bit rusty - his license is expired and he works only part-time. What do you guys think?

    * Is the 200amp sub reasonable and safe?
    - if not, what's my next course of action? Do I replace the main in the 200 amp sub-panel?
    * What gauge wiring do I need for the 200 amp sub-panel? I estimate covering 60 feet (give or take)
    * Do all 4 wires need to be the same gauge?
    * What's the best way to buy the wiring? Is there a large romex-like combo wire I can use?

    Thanks in advance!
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #4

    Mar 19, 2009, 08:29 AM
    Your questions with my response in red:

    His license is expired and he works only part-time. What do you guys think?

    I think the electrician you hire needs to have a valid license and familar with local codes. When someone says "he thinks", I wonder what the correct answer is. Is anyone reading the specs of the equipment in question?


    * Is the 200amp sub reasonable and safe?

    Yes, the 200 subfeed kit will allow the full 200 Amp to be drawn from the main meter/panel combo to feed a 200 amp subpanel. A branch breaker is different, and limited to 125 Amps.



    * What gauge wiring do I need for the 200 amp sub-panel? I estimate covering 60 feet (give or take)

    Either #2/0 copper or #4/0 Aluminum is allowed for a 200 Amp residential feeder.


    * Do all 4 wires need to be the same gauge?

    No, only the two hots and one neutral need to be full size,Either #2/0 copper or #4/0 Aluminum. The fourth wire, the equipment ground, can be either #6 copper or #4 al.



    * What's the best way to buy the wiring? Is there a large romex-like combo wire I can use?

    If a cable type feeder will work, you can use #4/0 aluminum SER cable. This can be exposed to weather, but must be protected from physical damage, if necessary.

    If there is any question on the equipment planned to be used, or the wiring method, perhaps the local inspector should be consulted to be sure the installation is done correctly to local code.
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
    Junior Member
     
    #5

    Mar 20, 2009, 08:57 AM
    Quote Originally Posted by tkrussell View Post
    If there is any question on the equipment planned to be used, or the wiring method, perhaps the local inspector should be consulted to be sure the installation is done correctly to local code.
    Thanks as always for the expert advice and reassurance. I just spoke with the county building inspector, and he said a 200 amp sub-panel with a #2/0 copper wire is fine. There was just one minor difference from the plan above - he wants a #4 copper equipment ground instead of a #6 (?).

    By the way, what size rigid conduit do I need here? 1.5", or can I get away with smaller? When you run a 60' connection with such thick wire, do you normally turn using 45 degree angles, or is 90 still pretty workable?
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #6

    Mar 20, 2009, 10:15 AM
    I bet he is getting the "ground" size from NEC Table 250.66 - Grounding Electrode Conductor, instead of the appropriate Table 250.122 Min Size Equipment Grounding Conductor.

    Seems he is a bit confused also. I note that he is a "building" inspector, and not an electrical inspector.

    Going up size to #4 instead of #6 is not a big cost difference with such a short distance, I don't think it is worth your while to argue the point with him. Especially since you're a DIY'er.

    Me on the other hand would stand my ground, no pun intended, and follow the National Electric Code, unless that municipality had it a written code listing this size wire for this application, which I doubt. But easy for me to say, I have a license.

    Min conduit size should be 2 inch, assuming 3 legs of #2/0 THHN and 1 - #6 THHN in Sch 40 PVC conduit.

    1.5" conduit is listed to handle 3 - #2/0 THHN, and I am not doing the conduit fill calcs to see if the #6 can be added.

    But take my word for it, you will be much better served using 2 inch for this run.

    We use 90 deg sweeps, or bend it ourselves in various deg bends however we need. Max degree of bends in one run point to point is 360 degrees.

    For this run, I would go no more than two 90 Deg bends and then have an LB, or some sort of pulling point if more bends are needed.
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #7

    Apr 8, 2009, 12:10 AM
    Quote Originally Posted by tkrussell View Post
    take my word for it, you will be much better served using 2 inch for this run. We use 90 deg sweeps, or bend it ourselves in various deg bends however we need. Max degree of bends in one run point to point is 360 degrees.

    For this run, I would go no more than two 90 Deg bends and then have an LB, or some sort of pulling point if more bends are needed.
    It turns out it's going to be difficult to bring the 2" conduit out from the sub-panel and up through the 2x4" top plate. There is a rafter resting on the area where the conduit should pass through the top plate. There isn't enough room in the cavity to use 90degree or 45degree sweeps. I need to figure out some way to skew the path of the conduit, perhaps an inch or two the right, to avoid the rafter. Should I try to buy some 2" Flexible NM Conduit? They don't seem to carry anything above 1.5" at my local hardware stores. Is there some easier way to make small adjustments in the path of the conduit?
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #8

    Apr 8, 2009, 02:37 AM
    We would bend an offset in the conduit to get around the rafter. Bending PVC is easy, of course, with the right tools and knowledge. Very difficult to illustrate and explain how to bend conduit here.

    Flexible conduit would help, using the proper connectors and couplings to insure a continuous raceway system. I could envision using Flex from the top of the panel uo through the wall cavity, through the plate and sweep into the attic and changeover to PVC conduit.

    Be sure to protect any conduit that passes through wood framing members where the outer edge of the conduit is closer to the face of the wood than 1-1/4". You can find nail plate protectors in both electrical and plumbing depts. Use nail plates to cover the path of conduit through wood framing to keep any nails or screws from dry wall, shelving, etc, from puncturing the conduit.
    Missouri Bound's Avatar
    Missouri Bound Posts: 1,532, Reputation: 94
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    #9

    Apr 9, 2009, 07:19 PM
    Wow... you posted this a year ago and still haven't finished it? Must be a UNION job.
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #10

    May 25, 2009, 06:02 PM

    Yep Missouri Bound, I've really dragged project out. There are so many others going on with the renovation, that I end up switching back and forth between priorities.

    Here's an update on the project -

    All of the schedule 40 PVC was rung, and at the ends that drop into the panels, I switched to flexible steel conduit for a few feet. With the shallow pitch of my roof it would have been impossible to get hard PVC through the top plate, but even the flexible steel coduit barely made it.

    We also pulled the copper through today. Man was that difficult! The cable wouldn't budge through any of my sweeping PVC 90s. I switched to using hard 90d junction boxes for every turn. The hardest part was getting the cable all the way through the second leg of the junction box. As the cable would get close to completely being inside the box, the 90d in the cable would make it nearly impossible to move. Frankly, I couldn't help wonder why the junction boxes were'nt designed to make this task a little easier.

    ... almost ready to activate the sub
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #11

    May 25, 2009, 06:09 PM
    These are just post-mortem questions for personal edification.

    (1) The cables coming off the Utility power lines are much smaller than the 2/0 cable running from my drop to the main panel, and from the main to the sub-panel. How come the utility company lines are a smaller gauge, and aluminum to boot? Does that mean I'm not really getting 200 amps to the main panel? Or can the utility lines simply be smaller because they're in the open air where heat will dissipate faster?

    (2) Are there any tricks to pulling a fat stack of 2/0 cables plus a #4 ground through 2" PVC? Getting through those 90d junction boxes was nearly impossible; there must be a technique I don't know. The turns were so tight, and the friction so great, that at one point a 2/0 cable actually lost the first layer of it's jacket. Luckily I saw it and patched it with tape; no copper was showing. That was way too close for comfort.
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
    Electrical & Lighting Expert
     
    #12

    May 25, 2009, 06:19 PM
    Quote Originally Posted by justincaseme View Post
    (1) Or can the utility lines simply be smaller because they're in the open air where heat will dissipate faster?
    This and the utilities follow their own rules.



    Quote Originally Posted by justincaseme View Post
    (2) Are there any tricks to pulling a fat stack of 2/0 cables plus a #4 ground through 2" PVC?
    Wire lube helps.



    Quote Originally Posted by justincaseme View Post
    Getting through those 90d junction boxes was nearly impossible; there must be a technique I don't know.
    I am not sure what you mean by "90d junction box".
    justincaseme's Avatar
    justincaseme Posts: 62, Reputation: 1
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    #13

    May 25, 2009, 08:56 PM
    Quote Originally Posted by stanfortyman View Post
    This and the utilities follow their own rules.
    I am not sure what you mean by "90d junction box".
    I meant the 'd' to be short for degree. Here's a picture of the junction box I'm referring to.
    Attached Images
     
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
    Electrical & Lighting Expert
     
    #14

    May 25, 2009, 09:05 PM
    Oh, OK.

    That's a conduit body, not a box. That is called an LB condulet, or LB for short.

    You weren't pulling through them, were you? They are pull points giving you a chance to pull wire more easily or if there are too many bends in a conduit system.

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