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Almot's avatar
Almot
Explorer III
Feb 22, 2015

Cable routing - conduit fittings?

I'm humbly asking advice from electricians and other DIY/reno etc people here.

Installed solar controller on the bedroom wall next to night-table. Didn't want it there, but with limited through-storage and recent floods, had to let this guy in :s

Breakers box and AGM battery bank are in under-bed through-storage, night-table is the ceiling of this storage, so battery is "close-ish" to controller. Pos wire from battery to controller via Pos bus is total 9.5 ft. Neg wire from trailer frame to controller via Neg bus is same 9.5 ft. Max current of controller is 30A, unlikely reached at sea level. Calculator for one-phase AWG 6 wire @10ft, 14V, shows 1.9% V-drop - fine with me.

Photo below: Big Baby breakers box in through-storage. Batteries are across the Baby on the right (not shown). Ceiling is the night-table, controller is on the wall few inches above the "ceiling".



Possible fittings on breakers box:


  • Wires from battery enter the box via 3/4 opening at the top - where blue fitting is.
  • Pos wires from controller -> through the storage ceiling/night table enter/exit the box via 3/4 hole, where grey cord grip is sitting.
  • Neg wire from trailer frame and Pos loads enter the storage via the hole in floor -> then to the box via 3/4 opening marked with red circle.

    Q1: I like grey strain relief connectors. But I also like conduits. Can't have both, can I?

    Plan:
    Keep strain-relief as shown, for 1 ft run to controller in split-loom to the storage ceiling hole via rubber grommet (and then Wiremold duct in bedroom).
    Battery cables from Baby box - again strain-relief and split-loom.
    Pos/Neg loads from red circle to the hole in storage floor - in a conduit.

    Q2: What fitting or nipple can be used for Pos/Neg cables from "red circle" in a conduit through 3/4" floor? Or at least 3ft conduit from the Baby box to the hole in the floor. I prefer a good conduit like Liquidtight, as Neg cable to frame is potentially 30A current, and storage will be used as a storage, with tools, pieces of lumber etc thrown in and out. Though blue corrugated ENT "hose" would probably suffice.
    • I agree that you are over thinking this, and I also like Liquidtight. A couple of large zip ties (cable ties) will keep the wires from falling into the conduit if the box somehow falls, which is really unlikely.

      Looking at your pictures, it doesn't look like it would be too hard to route the wires through the wall, instead of hanging where they are, then you could still use the strain reliefs. Maybe that would allow you to move the box out of the bedroom too.
    • if the box falls down to the floor due to earthquake, flood, end of the world etc.
      Over the top for sure. If any of those things happen who cares if the box falls???

      I ran the wires in cabinets, walls, etc so that they are not visible and all wires use split loom and some plastic clamps. SHOULD the 3 screws holding the box or the controller fail the wires will support the equipment. But I'd be wide awake during the earthquake with flashlight and absolutely the first thing I would check would be the box and controller. :S
    • Almot's avatar
      Almot
      Explorer III
      DrewE wrote:

      Why do you want a strain relief for wires that are being run in conduit? What will be applying strain to said wires that needs relieving? :h

      I thought that strain relief would protect wires from pulling out of the box - if the box falls down to the floor due to earthquake, flood, end of the world etc. OTH, conduit protects wires from damage while they are still attached to the box, but won't protect them from pulling out if the box drops down. I probably think too much :). Mexican air affected the brain.
    • Almot wrote:
      No problem attaching Liquidtight to the box, they have proprietary connectors.

      The problem I've been trying to solve, was to have a conduit AND a strain relief fitting on the box at the same time. Still don't know how, - other than leaving conduit loose at the box entry.


      Why do you want a strain relief for wires that are being run in conduit? What will be applying strain to said wires that needs relieving? :h

      As you surmise, it's not really possible to put two different sorts of fittings in the same knockout at the same time...blasted laws of physics and things like that.
    • Almot's avatar
      Almot
      Explorer III
      No problem attaching Liquidtight to the box, they have proprietary connectors.

      The problem I've been trying to solve, was to have a conduit AND a strain relief fitting on the box at the same time. Still don't know how, - other than leaving conduit loose at the box entry.

      Get rid of that blue fitting and use another like you have on the bottom of the box in the picture.
      Grey fitting at the bottom is a cable grip - strain relief, not a conduit fitting. Would like to keep this grip, but don't know how to connect any conduit to it.

      Westend, what is EXN?

      And, conduit to controller would NOT go through the "floor". It's cables to Pos loads and cable to frame that go out through the trailer storage floor - probably through $2 electrical box on the floor.

      Cables from breakers box to controller go up through the storage ceiling up into the bedroom. Storage ceiling is the bedroom night-table, see photo below. Bundle of wires at controller bottom are the wires coming from breakers in storage space below through the hole in night-table (aka storage ceiling in the earlier photos). Wires hanging from above are from solar panel. After the photo was made, I've opened 1" knock-out at the controller bottom, and clipped solar wire to the cab bottom above.

      It's bad enough having the controller brick on bedroom wall, and I'm trying to avoid having any conduit there. Will try Wiremold duct in bedroom, though it's still ugly. Ideally, controller belongs in the storage next to breakers box, but it's too tight unless I evict the batteries from storage space to the outside OEM perch. Maybe I will.

    • Lciuidtite and EXN have their own ---Box Entry Connectors. As you surmise, Licuidtite is over the top for protection and any other plastic conduit will do as well for your application. If you don't want the installation to be staring back at you in the future, get the proprietary connectors for the type of material you use.
      FWIW, my tail light and brake wires are led through EXN and I haven't noticed any wear or penetrations. I haven't driven in out too far in the bush, though.
    • I would get a roll of Liquid Tight flexible conduit and use that for everything. It's easy to work with and will give plenty of protection for the wires. I believe if you use a pull elbow like you linked to, you can insert the Liquid Tight conduit into the fitting and glue it with PVC cement just like you would with rigid Sch 80 conduit. Get rid of that blue fitting and use another like you have on the bottom of the box in the picture. For one #6 1/2" conduit should be OK, for 2 I would use 3/4". If you have the controller surface mounted, I would run the conduit right up to the controller, not just stop it at the floor....may as well protect the wires for the full run. I think 3/4" conduit needs a 1" hole IIRC....is this the info you were looking for?
    • Almot's avatar
      Almot
      Explorer III
      190 views, no suggestions. Surely more difficult question then "where to get 50ft ext3ension cord" :)

      Will this conduit body work for routing cables in conduit through 3/4" floor? And if so, how to connect flexible conduit like grey Liquidtight or blue corrugated conduit to these openings?

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