Announcement

Announcement Module
Collapse
No announcement yet.

1/2" sealtite fill capacity

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • 1/2" sealtite fill capacity

    I have a sub-panel in my detached garage fed from a 50A breaker. The cable runs through a length of 1/2" sealtite about 14 feet from the main panel to the sub panel.

    I'd like to install a larger sub panel and the replace the 8 space panel there now as it is full (powers my wood shop and the rest of the garage) with a 20 space Square-D panel, running a larger cable from the main panel, and increasing the breaker n the main to a 2 pole 60A or possibly larger breaker.

    Reason is I'd like to be able to split some loads to their own circuits (seperate lights from receptacles, garage door openers, etc) and we are also looking into installing solar panels on the garage roof and using the sub-panel in the garage as the tie point into the house electrical system.

    So I can not easily upsize the sealtite because it runs underground below a breezeway between the two buildings. Abandoning this conduit and running a new one is not something I want to do as it would involve tearing up an asphalt drive which is the only other path underground and I really don't want a conduit overhead running through the breezeway as it would be difficult to hide.

    Whats the largest size and number of conductors I can run through the existing 1/2" sealtite?

    Can I run two #6 THHN conductors and a ground through there? I think I will be over the recommended fill percentage but not sure.
    ---------------
    Light is faster than sound. That's why some people seem really bright until you hear them speak.
    ---------------
    “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
    ---------
    "Its a table saw.... Do you know where your fingers are?"
    ---------
    sigpic http://www.helmetstohardhats.com/

  • #2
    Re: 1/2" sealtite fill capacity

    here's a page with the NEC fill tables for various types of conduits:

    Williams Wholesale Supply - Technical Data

    The maximum allowable fill for existing conduits is 40% full. (NEC 2002 –Chapter 9, Table 1) and (Design Manual Chapter 850, page 840-15 (c) Conduit)
    Last edited by Plumber Punky; 02-08-2014, 11:29 AM. Reason: add info as i find it
    ~~

    ... it was plumbed by Ray Charles and his helper Stevie Wonder

    Comment


    • #3
      Re: 1/2" sealtite fill capacity

      Detached garage calls for a four conductor feed (2 hots, neutral and a ground) from the main panel to the sub, plus driven ground rods and separation of grounds and neutrals in the sub panel (separate ground and neutral busbars, and no neutral bonding screw). Can you directional bore under the driveway or get into the attic to run your feed from the main panel to the sub?

      Comment


      • #4
        Re: 1/2" sealtite fill capacity

        Out here detached garages, building are no longer allowed overhead wires. If it's exisiting, ok, but no repairs without going underground.

        I bored 2-1" pvc conduits 22' for power and low voltage.

        Rick.
        phoebe it is

        Comment


        • #5
          Re: 1/2" sealtite fill capacity

          Originally posted by Bob D. View Post
          Whats the largest size and number of conductors I can run through the existing 1/2" sealtite?
          Can I run two #6 THHN conductors and a ground through there? I think I will be over the recommended fill percentage but not sure.
          4, 10awg. But if you can run an undersized neutral, you can run 2, 8awg and 2, 10 awg (neut and ground) thru 1/2 lfmc.

          No, .125 sq inch fill is the max. You will be way over. I suggest you have your loads calculated to determine if you really need more capacity. Just because you need more circuits doesn't necessarily mean you need a larger breaker.

          Comment


          • #6
            Re: 1/2" sealtite fill capacity

            Thanks all. I'm thinking I might need more capacity if we install solar panels.
            My highest load would be heat pump/AC running + 3hp table saw + 1.5 HP dust collector + lighting.
            That would be the largest load with just me working in the shop.
            Not sure how big a solar array we might install, that's still a ways off I think, just trying to do this once and not have to upgrade again.
            ---------------
            Light is faster than sound. That's why some people seem really bright until you hear them speak.
            ---------------
            “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
            ---------
            "Its a table saw.... Do you know where your fingers are?"
            ---------
            sigpic http://www.helmetstohardhats.com/

            Comment


            • #7
              Re: 1/2" sealtite fill capacity

              I can't offer any solution to your problem, but I noticed this post from killovolt and have a question myself:

              Originally posted by killavolt View Post
              Detached garage calls for a four conductor feed (2 hots, neutral and a ground) from the main panel to the sub, plus driven ground rods and separation of grounds and neutrals in the sub panel (separate ground and neutral busbars, and no neutral bonding screw). Can you directional bore under the driveway or get into the attic to run your feed from the main panel to the sub?
              A year and a half ago, I had a 100 amp service run out to my detached garage, to provide for a future shop. I now have both 220- and 120-Volt multi-circuit capability there. The old overhead lines were removed. The service line runs off my main panel via a 100-amp breaker (in the basement of the house) and underground to the garage where a separate A/B sub-panel is located. The service line is stenciled:
              "Type SE-Style R XHHW 600V AA-8000-AL 3/C-2 AWG + 1/C 4 AWG"

              The underground line is in conduit with fitting and down about 16 inches or so. However, I don't recall seeing any separate ground rods and hence the question on your post: Is this a NEC requirement or local?

              The electrician who I contracted with IS a licensed "Master", who is quite reputable and more than busy.

              Thanks,

              CWS

              Comment


              • #8
                Re: 1/2" sealtite fill capacity

                Originally posted by CWSmith View Post
                I can't offer any solution to your problem, but I noticed this post from killovolt and have a question myself:
                A year and a half ago, I had a 100 amp service run out to my detached garage, to provide for a future shop. I now have both 220- and 120-Volt multi-circuit capability there. The old overhead lines were removed. The service line runs off my main panel via a 100-amp breaker (in the basement of the house) and underground to the garage where a separate A/B sub-panel is located. The service line is stenciled:
                "Type SE-Style R XHHW 600V AA-8000-AL 3/C-2 AWG + 1/C 4 AWG"

                The underground line is in conduit with fitting and down about 16 inches or so. However, I don't recall seeing any separate ground rods and hence the question on your post: Is this a NEC requirement or local?

                The electrician who I contracted with IS a licensed "Master", who is quite reputable and more than busy.
                Thanks,
                CWS
                Your panel in your garage is not a service, the panel at your house that feeds it is the service.

                Yes, A grounding electrode is required per 250.32 for a sub panel in a detached garage. It may not always be a driven ground rod but has to be one permitted per 250.52. The rules for grounding were also looser prior to the 2008 code cycle. An example might be using the metal frame of the garage as the electrode and supplementing it by bonding the metal water pipe.

                Just because you don't see a driven ground rod doesn't mean it's not not to code.

                Comment


                • #9
                  Re: 1/2" sealtite fill capacity

                  Originally posted by CWSmith View Post
                  I can't offer any solution to your problem, but I noticed this post from killovolt and have a question myself:



                  A year and a half ago, I had a 100 amp service run out to my detached garage, to provide for a future shop. I now have both 220- and 120-Volt multi-circuit capability there. The old overhead lines were removed. The service line runs off my main panel via a 100-amp breaker (in the basement of the house) and underground to the garage where a separate A/B sub-panel is located. The service line is stenciled:
                  "Type SE-Style R XHHW 600V AA-8000-AL 3/C-2 AWG + 1/C 4 AWG"

                  The underground line is in conduit with fitting and down about 16 inches or so. However, I don't recall seeing any separate ground rods and hence the question on your post: Is this a NEC requirement or local?

                  The electrician who I contracted with IS a licensed "Master", who is quite reputable and more than busy.

                  Thanks,

                  CWS
                  Your electrician did you wrong. SER cable is not rated for underground, conduit or not.

                  Type SE, service entrance cable is used to convey power from the service drop to the meter base and from themeter base to the distribution panelboard; however, it may be used in all applications where Type SE cable is permitted. SE
                  may be used in wet or dry above ground locations at temperatures not to exceed 90° C.

                  Comment


                  • #10
                    Re: 1/2" sealtite fill capacity

                    Johncameron,

                    Sorry for poor "service" label on my part... but, there is no metal framing or other grounding within the detached garage. The only apparent grounding is through the connection to the panel of the designated cable type which runs underground, though conduit back to the house and therein routed across the ceiling of the basement to the main panel. I see no other cable, grounds, etc. off that subpanel or anywhere inbetween.

                    RJ Niles,

                    Regarding the SE cable, I must admit I am a bit disturbed by this. Not only is this fellow reputable and a "master", but he also holds a degree and has been in practice for years. (He is the electrician who upgraded our main service when we bought this old house, eight years ago. At that time, he installed a new weatherhead, cable, and new load panel and swapped all the wiring over to the new panel. It was thoroughly inspected. During the installation of the new line out to the garage, he also took considerable pictures to document everything.

                    Edit: Well, I just took a closer look and the cable that is marked, as noted in my prior post, runs from the main panel across the basement ceiling (above the drop ceiling) and exits at the point where there is a conduit connection at the outside of the house. From the inside of the wall, I can see a clamp... but without opening the conduit cover outside, I don't know if that cable is possibly bonded to something else and in the garage, there is a solid conduit running from the outside connection directly into the side of the panel. Without removing the cover I can't see what is actually connected there. I do have a clipping of three wires: red-, white-, black-sheathed aluminum, each is about 1/4-inch diameter. As I recall, this is what was fished through the conduit. I presume there was a ground wire there too, but I don't have an example of that.

                    Do you think I need to call in another electrician to look this all over?

                    CWS
                    Last edited by CWSmith; 02-09-2014, 06:35 PM.

                    Comment


                    • #11
                      Re: 1/2" sealtite fill capacity

                      Cwsmith,
                      If there is a juction box before the conduit goes underground, he may have switched to a wired rated for under ground like THWN.

                      Comment


                      • #12
                        Re: 1/2" sealtite fill capacity

                        Thanks, I'll check it further. Right now I've got over a foot of snow on that side of the house, but will get over there later this week to see. I do remember him fishing wire though, as I brought out my shop vac to suck the initial string through the conduit. Also, I doubt that he would have been able to fish that SE cable through the conduit, even though there's good diameter to it.

                        More the concern is the grounding of the sub-panel and garage circuits. The panel out there is full-sized. Same panel as my main service panel. Only difference being is that there is no main breaker in it. I installed the mounting board on which the sub-panel is located and I as mentioned, all that is coming into that panel is the heavy conduit from his run. He then installed one circuit for my garage door opener and a second for a single outlet (GFI) and overhead lights.

                        I'm adding on to this garage this summer for my future shop and just want to make sure everything is up to par before I wire any additional circuitry.

                        Thanks again,

                        CWS
                        Last edited by CWSmith; 02-09-2014, 07:29 PM.

                        Comment


                        • #13
                          Re: 1/2" sealtite fill capacity

                          Originally posted by CWSmith View Post
                          ...there is no metal framing or other grounding within the detached garage. The only apparent grounding is through the connection to the panel of the designated cable type which runs underground, though conduit back to the house and therein routed across the ceiling of the basement to the main panel. I see no other cable, grounds, etc. off that subpanel or anywhere inbetween.
                          RJ Niles,
                          Regarding the SE cable, I must admit I am a bit disturbed by this. Not only is this fellow reputable and a "master", but he also holds a degree and has been in practice for years. (He is the electrician who upgraded our main service when we bought this old house, eight years ago. At that time, he installed a new weatherhead, cable, and new load panel and swapped all the wiring over to the new panel. It was thoroughly inspected. During the installation of the new line out to the garage, he also took considerable pictures to document everything.

                          Edit: Well, I just took a closer look and the cable that is marked, as noted in my prior post, runs from the main panel across the basement ceiling (above the drop ceiling) and exits at the point where there is a conduit connection at the outside of the house. From the inside of the wall, I can see a clamp... but without opening the conduit cover outside, I don't know if that cable is possibly bonded to something else and in the garage, there is a solid conduit running from the outside connection directly into the side of the panel. Without removing the cover I can't see what is actually connected there. I do have a clipping of three wires: red-, white-, black-sheathed aluminum, each is about 1/4-inch diameter. As I recall, this is what was fished through the conduit. I presume there was a ground wire there too, but I don't have an example of that.

                          Do you think I need to call in another electrician to look this all over?

                          CWS
                          Why not give the original EC or your ahj (local building department) a call? Personally, I would trust the Electrical contractor over the local inspector. They (the ahj) are notoriously wrong and often miss things like this. Bottom line is if you have a feeder going to a panel in an detatched garage there needs to be an electrode somewhere at the garage. Sometimes they use an uffer ground in the footing or a ground loop that cant be easily seen but the connection should be seen at the garage somewhere. One very important thing is that the neutral and ground connections are separate at the garage. A common rookie mistake is to use the green bonding screw in the sub panel neutral bar.

                          Comment


                          • #14
                            Re: 1/2" sealtite fill capacity

                            As long as there are 6 or less breaker handles it is ok not to have a main breaker. If you add cicuits and go over 6 handles, you need to add a main breaker.

                            Comment


                            • #15
                              Re: 1/2" sealtite fill capacity

                              CWsmith, If your install was done a few years ago and there is more than one circuit ran to your detached garage; It should be 4 wire with an electrode and separate ground and neutral connections.

                              Prior to 2008 nec (before 2011 or so) it was ok to run a 3 wire and keep the ground and neutrals together.

                              When the snow clears, post a few pictures so theres no confusion about how you describing it.

                              Comment

                              Working...
                              X