Hide Cables Outside House (Exterior Wall Conduits)

To conceal exterior cables safely, route them through listed raceway suited to the wall’s exposure, and use wiring approved for wet locations inside that raceway. Plan accessible pull points, support the conduit at code intervals, protect wall penetrations from water, and confirm local permit rules. A sealed conduit is not automatically dry or suitable for every cable.

Could you make the route to an outdoor camera, speaker, or other device disappear without leaving a weather or safety problem behind? The key is to plan the wiring method first, then choose a route and finish that protect the cable while keeping every box and splice reachable.

Plan the Route and Confirm Code Requirements

Start by identifying what the cable serves, where it begins and ends, and what conditions it will face. An exterior raceway may look like a simple cover, but its contents, fittings, supports, and wall penetrations all matter. Local rules and the adopted code edition also affect the plan.

Before buying materials, note whether the run carries line-voltage power or communications signals such as Ethernet, coax, or speaker wire. These systems can have different cable ratings and separation requirements. For new or changed line-voltage wiring, check permit and inspection needs with your local building department, also called the authority having jurisdiction, or AHJ.

Walk the route and record:

• The cable’s source, destination, and purpose
• Wall material, siding type, and any fire-rated assembly
• Exposure to sun, rain, sprinklers, snow, and physical impact
• The location of existing boxes, fittings, and possible pull points
• The shortest practical path that still allows access and a clean finish

Keep bends to a minimum. Under the 2023 NEC, a PVC raceway run cannot have more than 360 degrees of total bends between pull points. If the route needs more turns, plan an accessible box or conduit body to make the pull manageable. Confirm the code edition in force locally before installation.

Check Exposure, Access, and Required Clearances

Exterior raceways face more than rain. Sunlight, temperature changes, impact, and water that enters through fittings can all affect the wiring method. Plan for the real conditions along the full route, not just the spot where the conduit meets the wall.

The NEC treats the inside of an above-grade raceway outdoors as a wet location. That rule applies even if the conduit and fittings are intended to shed water. Use conductors or cables listed for wet-location use, and follow the product instructions. For suitable individual power conductors, THWN-2 is one common type; the correct choice depends on the circuit and installation.

Do not pull NM-B building cable through an exterior raceway on the assumption that a sealed conduit stays dry. NM-B is not listed for wet locations. Condensation can form inside a raceway as temperatures change, even when its exterior looks well sealed.

For exposed PVC, use electrical raceway listed for that purpose and identified as sunlight resistant where it will receive direct sun. Where a location is subject to physical damage, the wiring method must suit that risk. Schedule 80 PVC is one permitted option in some cases, but the AHJ determines whether the location needs that added protection.

Keep boxes, splices, and pull points accessible. NEC 314.29 generally requires boxes and conduit bodies to remain accessible without removing building structure or finish. Do not bury them behind siding, trim, or sealant. Also check required clearances and separation rules for power and communications wiring; these can vary by system and installation.

Choose Raceway, Cable, and Fill

Raceway is the protective channel for wiring. Select a listed type and size based on the cable or conductors, route, exposure, and allowed fill. A larger conduit can make pulling easier, but it does not remove the need to use listed wiring and approved fittings.

For exterior walls, electrical PVC is often considered where the route is nonmetallic and the exposure suits it. Use fittings listed for the raceway and conditions. Metal raceway or another wiring method may be appropriate where impact or other site conditions call for it. Confirm compatibility among raceway, fittings, boxes, and cable before installation.

Route condition	Planning choice	Check before installing
Sun-exposed wall	Sunlight-resistant listed raceway	Product marking and instructions
Area vulnerable to impact	Raceway suitable for physical damage; Schedule 80 PVC may be allowed	AHJ’s judgment for the location
Exterior raceway with power conductors	Conductors listed for wet locations, such as suitable THWN-2	Circuit requirements and conductor size
Communications cable outdoors	Cable listed for the actual wet or outdoor use	Manufacturer rating and any separation rules
Long route with several turns	Add accessible pull points	Maximum bend total between points

Raceway fill must be calculated from the applicable code tables, not guessed by eye. Under NEC Chapter 9, Table 1, the general fill limits are 53% for one conductor, 31% for two, and 40% for more than two, subject to the table’s notes and the raceway type. Use the actual conductor dimensions and the applicable tables to check the planned run.

Install Raceway, Supports, and Wall Penetrations

A clean installation depends on straight, secure runs and careful transitions at the wall. Mark the route before drilling or fastening, and check for hidden wiring, plumbing, and other services. Use the fasteners and installation methods specified for the wall and raceway.

For PVC, NEC Table 352.30(B) gives general support intervals of no more than 3 feet for trade sizes ½ through 1 inch, and no more than 5 feet for sizes 1¼ through 2 inches. The conduit also generally needs support within 3 feet of each box, cabinet, or conduit body. Confirm the table entry for the selected size and installation conditions, and follow the product instructions.

At a wall penetration, use a suitable entry fitting and make the opening shed water outward. Seal around the penetration with a compatible product where needed, but do not block siding drainage paths or rely on sealant in place of a listed fitting. Take care not to damage a fire-resistance assembly; that may require a specific firestop method.

Plan for expansion where the product instructions and temperature range call for it. Secure the raceway without crushing it, and avoid tight bends that make pulling conductors difficult. Use accessible conduit bodies or boxes where the route needs a pull point. Do not cover these after the wiring is in place.

Verify Wiring, Weather Protection, and Access

Before closing trim or calling the work complete, check that the installed route matches the plan. Confirm wire ratings, raceway fill, support spacing, bend total, fittings, and access. A careful visual inspection can catch many problems before they become difficult to reach.

Use this final check:

• Confirm conductors or cable are listed for wet-location use inside the exterior raceway.
• Check that exposed PVC has the required sunlight-resistant identification.
• Verify support spacing and support near boxes and conduit bodies.
• Count bends between pull points; keep the total within 360 degrees.
• Confirm boxes, splices, and pull points remain accessible.
• Inspect wall entries, fittings, and seals for a weather-shedding finish.
• Follow required testing and inspection steps for the circuit and local rules.

For line-voltage work, use a qualified electrician if you are unsure about circuit protection, conductor sizing, bonding, permits, or testing. For low-voltage systems, verify the cable’s outdoor rating and the device maker’s installation requirements. In both cases, the finished route should protect the wiring without hiding parts that must remain accessible.

Two Exterior Routing Examples

These examples show how the planning steps apply to common jobs. They are representative situations, not a substitute for checking the site, product listings, or local code. The right solution depends on the actual wall, cable, and exposure.

Outdoor camera on a sunlit wall: A homeowner wants to route a camera cable from an indoor equipment point to an exterior corner. The route needs sunlight-resistant raceway, cable rated for the outdoor conditions, and an accessible transition point. The installer checks the wall for impact risks, limits bends, and seals the penetration without covering drainage details.

Speaker wire across a garage exterior: A speaker cable must travel along a wall with several direction changes. Instead of forcing it through a route that exceeds the bend limit, the installer plans accessible pull points and checks the cable’s outdoor rating. If the route crosses areas vulnerable to impact, the wiring method must be selected for that exposure.

In my work, the recurring lesson is that the neatest-looking route is not always the best one. A slightly longer path with proper support and accessible pull points is often easier to maintain than a tight, concealed run that cannot be serviced.

Conclusion: Make the Route Neat and Serviceable

A good exterior cable route combines a clean appearance with weather protection, suitable wiring, and access for future work. Choose the path and raceway for the actual exposure, support it at the required intervals, and treat the inside as wet whenever the code says it is.

Before starting, confirm the local code edition, permits, and inspection requirements. Never assume that a sealed conduit is dry, and never conceal a required splice or access point. Those checks help keep the installation tidy, safe, and maintainable.

Frequently Asked Questions

Answers below cover common choices for exterior raceway and cable work. Always confirm local rules and product listings for the exact installation.

Can I run NM-B cable through conduit outside?

No. NM-B is not listed for wet locations, and an above-grade exterior raceway is treated as a wet location under NEC 300.9. Use wiring listed for the conditions instead.

Does outdoor conduit stay dry if I seal both ends?

No. Sealing may reduce water entry, but it does not guarantee a dry interior. Temperature changes can cause condensation, so the wiring inside must be suitable for a wet location.

What wire can go in exterior conduit?

The right wiring depends on its use and the installation. For some power circuits, suitable THWN-2 conductors are an option. Communications cable must also be listed for the conditions it will face. Check the product rating and local requirements.

Is Schedule 40 PVC allowed on an exterior wall?

It may be suitable in some locations, but the exposure matters. Use listed electrical raceway, including sunlight-resistant PVC where exposed to sun. Where physical damage is a concern, the AHJ may require a more protective wiring method; Schedule 80 PVC is one option.

How often should exterior PVC conduit be supported?

As general NEC guidance, support ½- to 1-inch PVC no more than 3 feet apart, and 1¼- to 2-inch PVC no more than 5 feet apart. Support it within 3 feet of boxes and conduit bodies. Confirm the applicable table entry.

How many bends can be between conduit pull points?

The total bend cannot exceed 360 degrees between pull points under NEC 352.26. Add an accessible box or conduit body when more turns are needed.

Can I hide junction boxes behind siding or trim?

No. Required boxes, splices, and pull points must remain accessible. Do not bury them behind siding, trim, or sealant.

Do exterior low-voltage cables need outdoor ratings?

They need a cable listed for the conditions where they are installed. Check its markings and the device manufacturer’s instructions, and follow applicable separation rules if the route is near power wiring.

Should I install exterior conduit myself?

It depends on the work and your experience. Line-voltage changes may require permits, inspection, or a licensed electrician. Ask the local building department about requirements before work begins.

(This article was written by one of our staff writers, Michael Holloway. Visit our Meet the Team page.)