How to Run Wires Through RV Ceiling: A Step-by-Step Guide

Inserting a hole in the roof of your RV seems a little scary, but there are times when you need to add new equipment or accessories to your RV.

You may want to install a solar electrical system, an extra cell phone booster, a Wi-Fi antenna, or TV and cell antennas. 

To run wires through an RV ceiling, you should find out what kind of wire to use, gather your tools and materials, and find the best place to drill the hole. Then, create the hole, soften the edges, install a protective device, run the cables through it, seal it, and run the wire along the walls.

In this article, we’ll show you exactly how to run wires through your RV’s ceiling safely and help you do a thorough and flawless job that’ll last for many years. 

Why Drill the Roof?

The exterior walls of an RV are usually not hollow because they’re reinforced with steel or other materials. So, to run a cable through your RV, drilling through the roof is probably your best choice. 

You may be worried about leakage or maladjusted wires, but there are ways to prevent that. Follow these steps to drill the perfect hole in your RV roof.

Find Out What Kind of Wire to Use

If you don’t have much electrical work experience, choosing the proper wires and calculating the wire sizes can be confusing.

But you should take it seriously; otherwise, you may run into safety or electrical problems later on.

Wires that are too thin can be hazardous, and the ones that are too thick are harder to work with, and you’ll have to spend extra money on them.

You should choose the wire size by considering its length and the amount of current that’s going through it.

If your wires aren’t thick enough, you’ll run into too much voltage drop, and the wires won’t be able to handle the electrical current running through them. 

Look for the maximum current in the technical specifications available for the appliances, lights, and other electronic devices you want to install.

This is listed in amps for DC devices. If it’s listed in watts, you should divide the number by your system’s voltage. 

To figure out the length of your wire run, measure the distance between its start point (most probably where you’ll put your amp) and its destination (somewhere on top of your roof).

Then double the number because you need both a positive and a negative wire to complete the circuit. 

Other than knowing the wire length and the maximum current, you need to determine the wire size.

The Circuit Wizard helps you estimate the proper wire size for your work if you enter the variables we mentioned: the wire length, the system voltage, and the max current. 

Gather Your Tools and Materials

RV Tool List – What Tools to Keep in Your RV Camper

Here’s a list of essentials you need to run a cable through your RV roof. Note that, depending on the devices you want to set up, you may need extra tools. 

  • Wire
  • A drill
  • Waterproof electrical cable gland or cable box
  • PVC conduit
  • Double-sided tape
  • Sealant
  • Sandpaper and hammerite 
  • Borescope inspection camera

Find the Best Place to Drill the Hole

You’ll need to carefully plan for the route you want to run the cables through.

Before getting started with the hole in your roof, identify the best place for it.

To do that, you have three options:

  • If your RV isn’t that old, you can contact the manufacturing company and ask them if they can send you drawings of its structure. The drawings show you a complete picture of what’s inside the walls and the ceiling, so you can easily find a good place to run your wires without hitting a pipe or an aluminum frame. 
  • If you have an old RV, don’t worry. There are other ways. You can use a magnet and glide it over walls or the ceiling, and wherever it sticks, you know there’s some kind of steel in there you don’t want to drill in. 
  • A final option is to find an opening in the walls. For example, you can remove excess plates, use your phone camera or a borescope inspection camera, and navigate it inside the walls or ceiling to see where barriers are blocking your way.

Create the Hole 

Once you’ve found the perfect spot for the hole, you’ll have to mark the spot from inside the RV and then drill a pilot hole from the inside until you reach the top of the RV. 

If the ceiling has a rubber coating, it’s best if you cut a small part of the rubber membrane before you start drilling.

Cut enough to prevent the hole bit from grabbing the membrane. 

Now you should go on top of your RV and locate the small hole you just drilled in the roof.

Grab your drill and widen the hole. The actual size of the hole depends on the number of wires you want to get through.

However, it’s best to keep the diameter of the hole up to 1 inch. 

Soften the Edges

You’ll need to smooth out the edges of the hole you drilled so it won’t damage the wires. You can do that using sandpaper, then apply Hammerite, glue, or sealant around the hole. Y

ou can also easily install some cable glands or PVC conduit inside the whole to do the job for you.

Install a Protective Device

There are three options you can use to protect your wires against bad weather conditions. You can use a cable gland, a cable box, or a PVC conduit.

PVC Conduit

The first option is to take a 1-inch PVC conduit and insert it into the hole. Leave most of it above the surface. Then it would be best if you used a sealant around it.

You can place the PVC cover plate on top. This way, you’ll prevent condensation or moisture from getting in your RV.

This method works well if you have only one or two wires to run through the roof. 

SealProof’s Liquid-tight Conduits are especially useful, and they come with the connectors you need to make everything tight and neat. They’re also easy to cut and very flexible. 

Sealproof Non-metallic Liquid-Tight Conduit and Connector Kit, 1/2-Inch 25 Foot Flexible Electrical Conduit Type B with 4 Straight and 2 90-Degree Conduit Connector Fittings, 1/2" Dia
  • Use with Sealproof straight or right angle connectors; can be used with any Type B metallic or nonmetallic conduit connectors. 50% lighter than metallic conduits, no sharp edges or burrs
  • Resists corrosion, abrasion, oil, water, acid, metal shavings, and rough environments; resists abuse, pull and crushing; outdoor, sunlight resistant, direct burial.
  • Applications: HVAC Equipment, machine tools, marine equipment, motors and controls, printing equipment, pumps, refrigeration equipment, transformer connections, outdoor lighting
  • Made from high quality virgin PVC. Smooth inside for easier wire pulling, no hazardous sharp edges or burrs, will not damage conductors. Light weight and lower installed cost. Quick installation, cuts with utility knife or PVC cutter. Integral rigid & flexible PVC construction
  • UL Listed Underwriter's Laboratories File No. E-129973; UL Rating: 80°C dry, 60°C wet. 70°C oil resistant. CSA Certified, Candian Standards Association File No. LL-84705, CSA rating - 18°C to 75°C

Cable Gland

You can use cable glands for smaller installations because they hold one or two cables at most. If you suspect you’ll need to install more equipment on your roof in the future, you’ll have to make a new hole and use another cable gland.

Plus, if you want to get to the hole and wires later on the road, you’ll have to remove the cable glands altogether. 

You should drill a bigger hole for a gland than when passing the wire through alone.

Tuparka offers waterproof and adjustable cable glands that come in packs of 50.

TUPARKA 50 Pack Cable Gland Waterproof Adjustable 3-16mm Cable Connectors PG7 PG9 PG11 PG13.5 PG16 PG19 Plastic Cable Gland Joints with Gaskets in PP Box
  • SUPER VALUE QUNATITY : 6 Cable glands model from PG7, PG9, PG11, PG13.5, PG16, PG19. 50pcs in total.These are totally enough for you to choose .
  • HIGH QUALITY:The cable glands are Made from high quality nylon PA66 plastic,Wildly use to cable fixing, wire splices, machinery control boxes, distribution panels, and electrical appliances etc .
  • STRONGLY WATERPROOF: Cable glands come with gaskets for the bulkhead mounting. It makes the seal against the inside of the surface.
  • WIDELY CABLE RANGE:Widely cable range from 0.12 - 0.63inch/ 3 - 16mm cable gland assortment . Ideal kit for your project needs.
  • EASY TO USE: Cable can be inserted through directly then tighten easily. No need for disassembly

Lokman’s 20 packs are also high-rated and work well. 

Cable Gland -Lokman 20 Pack PG7 Plastic Waterproof Adjustable 3-6.5mm Cable Gland Connectors Cable Gland Joints With Gaskets, Black (PG7)
  • PREMIUM QUALITY- Made of high quality nylon PA66 plastic, IP68 cable gland. Waterproof. Wide adjustable cable range. Special design of the clamping die and rubber part, wide clamping range, strong stretching resistance, no damage to cables and devices. Fantastic for cable fixing, wire splices, machinery control boxes, distribution panels and electrical appliances etc.
  • WATERPROOF- IP68 Cable glands come with gaskets for the bulkhead mounting. It makes the seal against the inside of the surface you're installing them on. thus are waterproof.
  • WIDLY CABLE RANGE- PG7 wire glands adjustable 3 - 6.5mm. Cable range: 3 - 6.5mm/0.12 - 0.26 inches. Thread O.D.: 12.5mm/0.49 inches. Thread length: 8mm/ 0.32 inches.
  • EASY APPLICATION - Cable can be inserted through directly then tighten easily. No need for disassembly.
  • 100% MONEY BACK GUARANTEE - We GUARANTEE QUALITY. If you not satisfied with our product quality or unhappy with the purchase, please contact us Via email. We, LOKMAN gladly accept your return within 30 days after your purchase for FULL REFUND with no questions asked.

Cable Box

These boxes are better options if you have more than two wires to run through the roof or if you’re going to add more wires in the future because they have multiple threaded openings.

You can also use a piece of conduit inside the cable box. 

Drill some holes in the side of the box—if it doesn’t have some already.

The holes should be big enough to fit the threaded side of the waterproof cable glands in them. Insert the cable glands and tighten them in the hole. 

Some cable boxes already have holes in the bottom. If not, drill a hole in it that matches the size of the hole you drilled in the roof of your RV.

Stick some double-sided tape to the bottom of the box to prevent it from getting dislocated.

Place some sealant around the hole and then place the cable box on top. Then you should fasten the box with screws. 

Cable organizer boxes, sometimes called cable management systems, come in all shapes, sizes, and materials.

For example, Bluelounge’s High-Density Plastic Cable Box lets you hide the excess wires, and it comes in various colors. 

No products found.

If you’re looking for something more sophisticated, we recommend Cabaley’s Cable Management Box Organizer, which comes with cable ties, clips, and sleeves. It also features an anti-skid design, which is pretty useful for an RV since you’ll be driving around a lot. 

Sale
Cable Management Box Organizer Set, Pack of 2 with Configuration Kit, Updated Anti-Skid Design, Large and Medium Black Boxes with Cable Ties, Clips and Sleeve. Covers and Hides Cords/Wires/Power Strip
  • 💪 GET MORE & BETTER VALUE FOR YOUR MONEY – 1 LARGE and spacious Cable Box 16 x 6.2 x 5.4", 1 MEDIUM Cable Box 12.6 x 5.3 x 5.1’’, 7 Cable Ties, 7 Cable Clips and a 39.4'' Cables Sleeve. Compatible with long high and wide surge protectors, Fits most standard 6-12 outlet power strips. At Cabaley we went to great lengths to bring you this Super Saver Value Pack ($41.95 market retail value)
  • 🛡️ SAFE, SECURE, HIDDEN, CLUTTER FREE – Store dangerous Plugs/Cords/Wires/Power strips away from your family and pets. Keeps cords hidden under desks, by the computer or next to the TV. Remove unwanted distractions and clutter to help create a more stress-free environment. The lid of the box is also available as a tray, use it as a charging station on your computer desk to store smartphones or other small devices. Fits wide and long surge protectors with extra space for cord slack and adapters.
  • ✔️ELECTRICALLY INSULATED, STRONG – Built tough with ABS high-density plastic, impact resistant, fire retardant, anti-scratch surface.
  • 🙏🏻 WE PROMISE - To always look to improve our products, all feedbacks and reviews are deeply looked into for actions to be taken.
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Run the Cables Through

Run the cable(s) through the PVC conduit or the cable gland and then through the hole and get them out of the other end. 

If you’re using a box, first, you should run the wires through the glands in the box’s side, then through the bottom hole, and then fish the wires out from the inside of the RV and get it to where you want.

Afterward, you’ll need to tighten the cable gland around the cable. 

Seal the Hole

Before using sealant on your roof, clean the surface with alcohol thoroughly.

If you’re using a cable box, place some Silicone or Dicor sealant around the hole and then place the cable box on top and press it until some come up through the openings.

Then you should fasten the box with screws. Place some more sealant around the box’s outer base and on the fastened screws to make a waterproof environment. 

Be sure to put on some sealant on the edges of the box before you put the lid on if it doesn’t have a bead of silicone or caulking itself. Then use screws to fasten the lid. 

Sale
Dicor 501LSW-1 Self-Leveling Lap Sealant, 4 Pack
  • Helps create a seal along a roof's edges, around air vents, vent pipes and screw heads
  • Compatible with any roofing material
  • Offers excellent adhesion to aluminum, mortar, wood, vinyl, galvanized metal and concrete
  • Improves the ability to continuously seal and remain flexible
  • UV stabilized to prevent deterioration and discoloration, will not stain or discolor any material to which it is applied

If you’re using a cable gland or PVC conduit, place some sealant around it, as we explained before.

You can use some silicone sealant on both ends of the conduit after running the cables through it, so you can pull out the wire later if necessary. 

Remember to place some sealant on the inside of the RV around the hole when you’re done. 

Run the Wire Through the Walls

If you’ve chosen to line up the exterior opening with an interior wall, then you should continue to navigate the wire in the walls after you ran it through the roof.

You may want to fish the wires out from an opening you made somewhere in the walls, so it’s best if you use a borescope camera to guide the wire inside the walls until it reaches the opening.

If you want to run wires in the back of your cabinets, you can drill a hole in the top back corner of the cabinet. This way, the wires go in the cabinet easily and don’t interfere with the things you put inside. 

Safety Tips

As with any operation that involves electricity, to run a wire through your RV ceiling, you need to take safety seriously.

Consider the following safety tips: 

  • Be sure to disconnect your RV’s battery before you get started. Most RVs have a switch that breaks the connection between the fuses providing power and the battery.
  • If you can’t find a roofed parking space for your Rv, don’t choose rainy days for the work. Be sure to check the weather for at least two days ahead before starting the process because it may take more than one day to finish the job. 
  • Before drilling the hole, make sure the roof is dry and thoroughly cleaned with alcohol. 
  • Gather all your equipment in a container that you can put on top of the roof, so you reduce the risk of them constantly falling down. 
  • Be careful with the sharp tools, especially the drill. Never make any adjustments while it is on. Don’t clean away chips with your hands. 
  • The hole you drilled can have sharp edges. Don’t cut your fingers with the hole. 
  • This goes without saying, but be careful not to fall down from the roof!
  • Wear tight clothing throughout the process. 

Final Tips

  • Consider all the alternatives. If you want to go through with this project, take some time, and consider all the alternatives first. Think about any future equipment you may want to install on your roof and then decide on the place you want to drill the hole and the tools you’ll need. It’s best if you get to know your existing options and cable paths. 
  • Look for ducted air conditioning. If you’ve got ducted air conditioning somewhere in the ceiling, it’s a good idea to consider fishing the wires through them. You may still need to create holes in the ducts, though. Remember never to run wires through the heating ducts, unless, of course, you’d want to start a fire! Although heating ducts usually don’t get that hot to melt wires, it’s best to be cautious.
  • Look for holes in existing plumbing. You can also look for holes drilled for the existing plumbing. They are usually large enough. If they are sealed, you can remove the seal, run the wires through, then close the opening again. 
  • Use your roof rack. If you have a roof rack on your RV, it can be an excellent option to fish wires through one of the existing rack support footings. You can remove one mounting bolt and pass your wire through that hole. 
  • Use the refrigerator vent. If you have a refrigerator vent up on the roof, you can drill a hole in one of its aluminum or steel walls and, using a cable gland, pass the wires through there and behind the refrigerator. Make sure you have all the equipment you need before you start the process—especially enough cable. 
  • Diagram your system. If you want to install a complicated system, and you can’t get it straight in your head, it’s best to draw out your system and diagram how everything is supposed to connect. If you’re installing antennas, be sure to install them at least a foot apart to keep them from interfering with each other. 
  • Run a string with every wire. Whenever you run a wire, remember to run a string with it so that you can replace the string with another wire in the future if you need to. 
  • Mark the positive and negative wires. Remember to mark the positive and negative wires, so you won’t get them confused later. After the wires are through the roof and before you seal everything up, it’s best if you test them with a cat5 tester. 
  • Use stainless screws. Using stainless screws for the cable box can really help prevent it from moving and loosening the seal.

Conclusion

As we talked about, you should consider all your options before drilling through your roof.

You can consider passing the wire through ducts, plumbing holes, roof rack footings, or a refrigerator vent.

After deciding about the spot, gather all the equipment you need and then dig in! 

First, drill a small hole from the inside of your RV, and then a big one from outside.

Then soften the edges of the hole, install a protective device, and run the cables through. Seal the hole carefully and continue running the wires through the walls if that’s part of your plan. 

Be sure to choose the wires you want to use wisely, and think about the protective device that’s best for you.

Consider the equipment you may want to add to your RV’s roof in the future.

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