cable routing for solar - vent pipe or drill roof?

[urbanMark]

Hello Everyone,

First post here. I'm sure this has been asked before and I did search but came up empty.....

I'm installing solar on my 2011 Eclipse Milan 25RKS TT. I've already built a custom enclosure for my dual AGM batteries and wired up the MPPT controller, breakers, fuses, disconnects, etc (I'll add some photos if I can figure out how), but the one remaining task is to route the cables from the roof to the controller. My fridge is near the rear of the trailer, so that isn't an option, and unless I want to tack conduit to the outside of my trailer (yuck), I'm looking at one of the following:

1. Use the grey water vent pipe. This comes out under the bathroom sink and is conveniently next to where all the electrical comes up from under the trailer - so I wouldn't need to cut a new hole in the bottom of the trailer. It would also keep the wiring out of site and away from storage areas. My concern is fishing the wire out of the pipe and sealing the hole well enough to prevent a smelly trailer.

2. Drill the roof over the bedroom closet. Straight forward and shortest cable run, but the closet is over the main storage bay - so wires would run through the storage bay (to get under the trailer) and would be a snag point for loading/unloading the storage area. The closet is also quite narrow and I'm sure the wires would be visible no matter how well I tried to conceal them.

Anyone had experience with the vent pipe method? Other options I should consider? Ideas for dealing with the wires through the storage bay?

Thanks!
Mark

[Clay_Smith]

Mark,
Up on the roof, you remove the vent cap from the grey vent pipe and fish the wire down inside the wall beside the pipe without it ever entering the pipe. If the hole through the roof for the vent pipe isn't large enough for the wire to enter beside it, you may have to remove the entire vent cap form the roof to enlarge the hole. Then reinstall vent cap while sealing it down with some fresh Dicor sealant.

[FLY_4_FUN]

For sure drilling the roof is last resort. Pop the cap off your grey or black tank vents and see if theres room to fish your wires next to the pipe. Barring that you can run the wire down the vent and tap into the actual pipe down where you can route it to your charge controller while sealing up the pipe.

best of luck

[RoyB]

I already have been using the PVC Electrical boxes from Lowes and going through the side of the roof into ceiling mounted cabinets for my Ham Radio antenna wiring.

I don't have solar panels yet but will most likely follow this idea with the required cables...

Using the PVC electrical boxes on both sides of the wall and cut a large hole thru the center of each box. Then you can glue in a PVC short pipe to connect the two boxes and seal up good all around it... Never been a problem doing this for my Ham Radio antennas extending above the roof.

I have used this idea as well inside the floor mounted cabinets where alot of wiring is put in going to the underside of the trailer... Makes for a great loop around the the floor of my trailer for wiring. All protected inside PVC lines and electrical boxes with sealed lids...

These kind of PVC Electrical Boxes come in all sizes and many different combinations of ports.

google image

Roy Ken

[SoundGuy]

urbanMark wrote:
I'll add some photos if I can figure out how ...

Upload your pics here, copy the url, and paste it into your post. Use preview to ensure your pics aren't too large but if they are just size them accordingly by adding "width=450" or some similar number so the pic size is to your liking.

[westend]

Size the hole in the vent pipe large enough to accept either a weather-proof box entry fitting or a grommet. I'd use the latter since it is a friction fit. Lead your wiring down through the vent pipe and through the grommet,leaving the grommet around the wires, loose, outside the pipe. After you have the correct length pulled, slide the grommet over the wires and into the hole on the pipe. Apply liquid sealant to the grommet to insure sealing.

[austinjenna]

I went down the grey vent pipe as well. Just seal it up good and you should be fine. I have had no problems with mine at all.

[Almot]

urbanMark wrote:
...the one remaining task is to route the cables from the roof to the controller. My fridge is near the rear of the trailer, so that isn't an option

Not an option because ....? Too long run or don't know how to route it inside in aesthetically pleasing way?

Voltage drop with 24V panels in series isn't a big issue, with #10 MC4 cable (you cut it in half) at 30-40ft run V-drop will be negligible. With more than 500W or in parallel - can't say, need to run the numbers. There are also #8 MC4 extensions for those who need it.

I did it this way with 2*250W in series, #10 MC4. About 18 ft from fridge vent to trailer front, inside routing through the wall cabinets, and then under the Wiremold cable covers when not in the cabinets. 7ft drop down to batteries plus another 5 ft interconnect btw two panels, total 30ft one way. According to Southwire calculator this results in less than 2% voltage drop.

There isn't much need to drill the roof with 24V panels. With 12V panels and PWM - yes, those are often installed with a hole in the roof and junction box.

Yes, somebody run it through the black tank vent - not the grey tank, as I recall - doesn't matter, it's not venting to inside anyway. Pics are posted on that List.