The Secret Life of Wires

ScottG · June 2021

Running wires into the T@B--particularly with the 320--has always been a bit of a challenge. As part of adding an auxiliary battery harness, I wanted to run two new wires from the front tub to the converter area under the driver's side bench. Rather than find an easy (but less elegant) solution, I decided to run these new wires along with the others entering from the junction box mounted near the front of the frame. Enthusiasts of T@B anatomy (and T@B yoga) might be interested in a synopsis of the project.

From the junction box, a collection of several wires passes through a small plastic sleeve inserted in a hole in the floor (green circle). The hole is drilled just aft of the curved front wall of the trailer, and is strategically placed in the tight space between the kitchen cabinets and the black tank. The wires than run behind the toilet and duck into a length of conduit that carries them along the outside wall under the shower and eventually into the space under the driver's side bench (purple circle).

Image: https://us.v-cdn.net/5021717/uploads/editor/q1/vvsndtnvvfdx.jpg

Of course, the existing plastic sleeve was just big enough to contain the existing wires. Adding any more would require a new hole, or a bigger sleeve. I opted for the latter, recruiting the barrel of a 20cc syringe as a replacement. Here's the new sleeve in place, shown from both the outside and the inside. The inside was accessed (awkwardly) through a small opening in the left wall of the lower kitchen cabinet. You can see how tight the space is, and why you would have to be very careful drilling any additional holes in this area.

Image: https://us.v-cdn.net/5021717/uploads/editor/hv/yte9a4l6izav.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/h2/o3gfex23vfyx.jpg

Employing no small amount of T@B yoga, I was able to feed two new 10g wires up through the sleeve, across the space behind the toilet, and down into the conduit leading the converter area.

Image: https://us.v-cdn.net/5021717/uploads/editor/zi/q9jpl9otkaci.jpg

This was a challenging project, mostly because of the constricted working space, but I'm very happy with the outcome. In my case, access was facilitated by the additional hole I cut in the bathroom wall a few years ago to fix a plumbing leak. However those with skinny arms and an abundance of patience might be able to do this through the existing hatch using stiff electrical fish tape.

gulfarea · June 2021

@ScottG Great job! Remember this if you don't protect wires where they go thru places where they can chafe like Scott did, all the smoke that the wire factory put in the wires when they were made will get loose and you will never get all that smoke back in the wires like the factory installed smoke! Art

Dutch061 · June 2021

Ah yes, the "magic smoke" which is the proprietary secret to all things electrical and electronic. Let that smoke out and it is impossible to put it back in to restore function or make it function properly again....

Brad

Pintoplumber · June 2021

Boy, here I was all set for some wire hair fox terrier stories. Oh well.

YanniLazarus · June 2021

Thanks. Now I know exactly where the screw driver that i lost changing my water pump is! Kidding aside, really nice work.

Pintoplumber · June 2021

Dutch061 said:

Ah yes, the "magic smoke" which is the proprietary secret to all things electrical and electronic. Let that smoke out and it is impossible to put it back in to restore function or make it function properly again....

Brad

This stuff?

johnfconway · June 2021

Pintoplumber said:

If any company needed smoke it was Lucas. In the 70s, folks who owned Triumph and BSA motorcycles didn't get to ride much. The Lucas wiring harness was too often acting up.

Dutch061 · June 2021

Ah yes, Lucas electrics, insulation got brittle with age and fell of the wiring. Bundles of bare wires everywhere. However, I didn't know they (Lucas) put the magic smoke in a jar!

Brad

dragonsdofly · June 2021

That stuff looks to be as rare as a functioning tab encabulator! And about as valuable. -Denise

JeffroNC · June 2021

Lucas headlight switch positions:
OFF
DIM
FLICKER
😁

Michigan_Mike · June 2021

Nice work Scott! I installed the SeeLevel system in my former 2015 320 and know exactly what you were referring to here. Speaking of T@B yoga, how many Aleve did this project require? 😂

cafyrman · June 2021

Ah, Lucas - Prince of Darkness

ScottG · June 2021

Having occasionally liberated magic smoke through my own negligence, I understand the importance of keeping it contained. It's a relief to know replacement smoke is available. However, having now destroyed my one syringe as part of this project, I no longer have a way to re-inject it. :-/

On a related note, I briefly considered simply drilling another hole in the T@B floor, just to the outside of the existing one. My thinking was I could just shove the new wires in the new hole and eventually they would appear somewhere I could grab them. However, as you can see from my photos, this approach would have released something equally odiferous--but considerably less magical--than smoke. :-p

Bayliss · June 2021

@ScottG, your last comment and photo on the "no drill zone" is very helpful, so thanks for that. It demonstrates how it is very advantageous to take your time and think things through before blindly drilling a hole and assuming there are no obstacles (such as a black water holding tank) in the path of your drill bit.

I am curious as to why you have added an "auxiliary battery harness."

ScottG · June 2021

@Bayless, I wanted an easy and elegant way to hook up a spare battery carried in a separate box. I have no room in my front tub for a second battery--and the occasions where I might actually need one are few and far between--so major modifications to the existing tub (which I like just fine) seemed like overkill.

You can see the details of the install here. Scroll back to my comment of June 11.

Bayliss · June 2021

Thanks, @ScottG. I took a look. Slick setup. You do nice work.

ScottG · June 2021

Thanks, @Bayliss. It was an impromptu project that I dove into without much of a plan, so I'm glad (and maybe lucky) it all worked out. The lack of accessibility to that space was the first (and only) misgiving I had abut the design of the T@B when I first got it.

@Michigan_Mike, your comment prompted me to look back at your old posts on the SeeLevel install. It looks like the openings for the propane lines under the fridge are viable alternative for running wires that doesn't require tinkering with the existing harness. Seems like the fish tape really helped--I thought I had everything in my tool cabinet, but I think I should add that.

Poking around those old discussions I also found this post by @Matt that T@B anatomists might appreciate. If only popping out the shower floor was a simple task! :-)

BrianZ · June 2022

ScottG said:

...
@Michigan_Mike, your comment prompted me to look back at your old posts on the SeeLevel install. It looks like the openings for the propane lines under the fridge are viable alternative for running wires that doesn't require tinkering with the existing harness. Seems like the fish tape really helped--I thought I had everything in my tool cabinet, but I think I should add that.
...

I came across this while re-searching for discussions about routing power lines through the front of a 320, as my port is max'd out & I'd need a need hole to run the additional recommended 8G battery ground and possibly a positive line as well. I've got a couple comments/questions..

Regarding Mike's suggestion, I would not run power lines near a propane line. Imagine if a ground line was close to a propane hose when one of our experienced Tabbers dropped a wrench that connected his T@B frame to the battery positive terminal. It sent a very high short circuit current through the frame & returning from deep inside the T@B through the white main ground wire back to the battery; resulting in wires hot enough to smoke & burn the insulation off the wire. Imagine what that heat could do to a rubber hose with propane inside; especially if someone didn't act as quickly as he did to safely defuse the situation.

Now, a question about your first two photos showing that clever syringe trick, and what's located in the spaces above..

No question that you would NOT want to drill farther to the right of the syringe, but what about drilling about 3 or 4 inches to the left, going inside of the kitchen cabinet shown in the first photo? From there, it would be easy to route wires through a hole in the area where the water pipes go through the cabinet wall, then into the main electrical conduit running from under toilet to converter area. (I realize it's a bit of a "no-no" for electricians & their legal codes to run power lines through cabinets, though this could be mitigated by adding conduit for protection).

Another option, as others have done, would be to drill a few inches farther to the rear (& presumably through the floor rather than a wood beam). As pointed out in a previous post, this has been done before, but requires temporary removal of the corrugated plastic barrier underneath for access. However, using this space behind the barrier offers a bit of extra protection from road dirt, though wires would need to be routed back out though a seam.

I do like the idea of drilling through wood (rather than just the floor), which provides a solid base for using screws in the flange of a conduit to hold it in place. I have constructed a conduit with flange from parts laying around that would fit a 3/4" hole & can be screwed down. Also thinking I might try a stud-finder on the wood beam to possibly avoid any screws/bolts that fasten the front wall to the wood cross beam.

Anyway, I would be interested in any thoughts you might have on this?

ScottG · June 2022

@BrianZ, at first pass I don't see any reason why a new hole behind or to the cabinet side of the existing hole wouldn't work. I would just be sure to double-triple-quadruple check to make sure you are not drilling into anything important. different T@Bs may be configured a bit differently, so what works on one may not work so well on another.

BrianZ · June 2022

Thanks, @ScottG, good advice. I'm past the double check, but probably not at the quadruple check level yet!

Construction photos I've seen don't show any structures in or under the floor of that cabinet. I don't believe there is any visual access to that tiny space between the bottom of the cabinet and the trailer floor, so the best I can do at this point is check surfaces on the outer sides of that space, and so far I haven't seen any kind of lines going through that corner, except through the wall.
Thanks for your opinion & advice. I may try a small bit first for a pilot hole & explore with a bent wire.

Denny16 · June 2022

Brian, You could drill into the floor inside the galley cabinet. ImwouldI go closer to the front wall, but enough to miss the front beam. Instead of using PVC pipe bits for a conduit, I would get a marine wire gland that can go down into the hole,from inside the cabinet, caulk in into place to seal,
the exit in the Azdel floor, and screw it’s mounting flange into cabinet floor. This would give you a seal around the cable.

For wire, I would use a Marine AWG no 8, two cable in a jacket, that would fit the rubber gland in the unit. While a little more expensive, the marine cable is water proof, tinned stranded wire, that will give you the ground and a positive buss wire, and the tough jacket on these cables offer with wire some protection from chafing damage going through the plastic bottom bit.

I would use an additional wire pass through flange going through the Tub (bucket) if the existing wire routing hole isn’t big enough. You do not want wires rubbing against the edge of a hole in the bucket that could cut through or damage the wire’s cover. Good luck with your project.

Materials:
Wire - https://www.amazon.com/Ancor-121510-Marine-Duplex-Cables/dp/B000NUYBW0/ref=sr_1_43?keywords=marine+cable+gland&qid=1655135280&sr=8-43

Bulkhead wire gland: https://www.amazon.com/Seaview-Waterproof-Plastic-Cable-Diameter/dp/B01K6TFJNW/ref=asc_df_B01K6TFJNW?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80264466333904&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4583863992799545&psc=1
Cheers

BrianZ · June 2022

Thanks again, @ScottG. Your advice paid off after some additional sleuthing showed there are indeed things under the bottom of the lower sink cabinet that I would NOT want to drill into.

Below is the view looking from inside bottom left of sink cabinet into that little access panel facing the bathroom, which gives access to the black tank electronic SeeLevel sensor and also this view (in a mirror I put inside there at an angle) of where the cables enter the floor from the front between the tank & the cabinet. For orientation, the plywood panels in the mirror at upper left are the same ones that I'm looking through at bottom right in the photo..

Image: https://us.v-cdn.net/5021717/uploads/editor/m7/nvurzwxdahmt.jpg

The mirror view clearly shows that both AC(yellow) & DC(black & white) lines run underneath the cabinet floor to supply the fridge with power.

It may still be possible to drill into that space from underneath, but only if precautions are taken to protect these wires, such as by sliding a sturdy sheet of metal under the power lines while drilling through the floor.

By the way, it looks like that conduit is half inch ID (and maybe 5/8" OD). Not sure what the depth of the hole is, but I plan to measure that too.

Also, while it may seem easier to drill just to the rear of the existing wiring hole, that also involves a bit of the unknown.. For example, factory tour photos show that the front wood cross beam (in which the existing wires/conduit shown above pass through) is screwed to a second wood beam that is inside a rectangular hollow metal beam. That would present a bit more of a drilling challenge, not knowing exactly where the two beams are joined, as well as dealing with layers of both metal & wood. Being able to line up with the existing hole in the same beam shows you where you are, though I'd probably want to move a few inches laterally to avoid weakening the beam in one spot.

[Deleted User] · June 2022

Magic Smoke?!?!?!...You're joking right?

BrianZ · June 2022

Thanks for all the ideas, @Denny16. When you said "enough to miss the front beam", were you referring to the wooden floor beam in front, or the steel frame underneath? It sounded like you might be talking about going through the wall & diamond plate?
Also, what is the "bucket"?

I am now thinking maybe I should run both pos & neg lines, just to avoid having to do it again if I ever wanted faster charging. Hmm. That marine cable is quite expensive, but I like the idea of running the pair.

Denny16 · June 2022

Brian, drilling behind the front floor wood beam and between the metal beams.
The bucket I was referring to the front Tub where the battery is on the 320. Corrected my post, thanks.
Cheers

BrianZ · July 2022

New Ground Wire Floor Hole Location & Conduit Added:

The need for a new ground wire has been previously addressed..

https://tab-rv.vanillacommunity.com/discussion/comment/180974/#Comment_180974

My purpose here is to show how I was able to successfully drill a new conduit hole to run a ground wire from the junction box under the tongue to the ground bar next to the converter in the electrical compartment. The new hole in front is similar to the factory location in our T@B320s shown below with the aid of a mirror, but it is 6 inches more toward the centerline and under the bottom shelf of the kitchen cabinet at the right..

Image: https://us.v-cdn.net/5021717/uploads/editor/3h/xil8zwqcm14k.jpg

This space is accessed by removing the small cover panel screws at the front left corner of the bottom cabinet shelf under the sink. The green line shows the routing of the new wire from under the shelf and up into the space behind the toilet, following the same route the other wires take through the large conduit that runs front to back. (I took this photo using a mirror & cell phone, then flipped the image L-R in my photo editor to get the normal perspective instead of a mirror image).

Below is another view taken with a small 180° camera showing that there are both AC & DC cables under there that needed protection. (Thank you @Bayliss and @ScottG for your advice to check &recheck before drilling, which helped save me from damaging them!)

Image: https://us.v-cdn.net/5021717/uploads/editor/vx/i0jbyeytaz01.jpg

I was able to place two sheets of aluminum flashing under the wires for extra protection.

The next photo shows a mockup I tested using a scrap of flexible clear vinyl tubing that fit perfectly in a 5/8" drill hole..

At the outside end of the tube, I cut 4 tabs to secure it under the front edge of the trailer using aluminum screws..

I also cut a piece of 1/8" rubber sheet to cover the tube for extra protection before applying caulking to the area..

I realized that before drilling or cutting the conduit tube, I would need to know the thickness of the floor, not only for the length of the conduit tube, but so I could wrap my drill bit with a piece of masking tape to let me know when I've reached the depth where the drill bit is about to punch through, so I could proceed with caution. To measure it, I used a straightened paperclip which I filed to a rounded tip so it wouldn't damage wires & pushed it down inside the existing conduit. The arrow in the photo below shows the tip of of the wire where I measured the length to be subtracted from the overall length.

After also subtracting the half inch length of conduit inside, I found the floor/hole would be about 1-7/8" thick/deep & length of tube needed was about 3".

Below are my measurement notes & sketch of that floor area (ignore parts marked in green, before I realized I didn't need to go through the cabinet floor itself)

Next, I measured over 6" from the center of the existing conduit (using my 6-inch ruler of course!😃)..

Then marked 6" where the green circle is shown below..

Note the location for the new hole is just above the right side of the junction box, and clear from existing outside wires for getting in there with a drill.

I marked the spot & cut an X in the plastic membrane, and folded it back for drilling..

And a closer view of the new hole..

I folded the corners of the plastic sheet into the hole, inserted the new conduit tube & secured the conduit parts in place.

Below is the completed cable in place, with a cable clamp holding it at top, and ring connector soldered on the end & sealed with heat-shrink tubing..

It is jam-packed inside that box, so I had to use the most distant hole in the box with space left for a large wire. I will likely need to use the bottom hole for the remaining ground wire going from this box to the battery. I just hope that ground terminal is long enough for one more cable.

I'm not sure if there's enough room, but should I also run another one to the frame from here?

I managed to get the next shot of the conduit in place on the inside, under the cabinet bottom shelf..

And finally, here are the new ground wires in the electrical compartment..

The green wire at left on the bus bar (& at bottom right) is the new one just installed; while the one on the right is another new one that goes to the Alde cabinet..

I attached this Alde Ground Wire at the provided ground clip. I only needed to add a screw. Strange that Alde provides for a ground wire connection on the cabinet, but one was never installed at the factory.

Next on my list will be completing the final path with another piece of 8G ground wire going from the main J-box to my battery junction box that I added in the tub (it connects all DC ground wires to the another box holding the shunt for the Victron battery monitor). Sorry, wires, but your new life in our T@B is now a little less secret.

By the way, I have given up on the idea of using an anode rod in the glycol tank, and will instead pursue this route of proper grounding along with the new Alde fluid to address any remaining corrosion issues.

Denny16 · July 2022

Nice job Brian, looks like this should work.
Cheers

BrianZ · July 2022

Thanks, @Denny16, and also thank you for your previous recommendations for the marine cable glands. I was afraid they might be too bulky for this very tight space, and then I realized I could do it with materials on hand. The real challenge is going to be trying to fit even one more cable on that ground peg inside the J-box to get back to the battery. I may need to replace that one with a 6G instead.

Pintoplumber · July 2022

We have a wire haired fox terrier, commonly called a wire or foxie. I thought this was going to be a thread on dogs.

Denny16 · July 2022

Brian, a larger ground wire is best to run to the battery box, and add a marine ground buss bar i
on the inside to connect the individual a smaller ground wires to the larger wire going to the battery box. An AWG 6 is rated for 30amps on a short run like this, and should be large enough, as the TaB is only a 30-amp system. We used AWG4 in boat ground buss runs, where the length of the cable was greater than 20-feet.
Cheers

BrianZ · July 2022

Who knows, @Pintoplumber, maybe foxies have a secret life too!

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