Adding a new home phone can seem daunting, but you can do it without calling in a professional if you’re handy around the house. . Usually, you won’t need to run an entirely new phone line back to your telephone service box, but you may need to install a new phone jack.

In this guide, I’ll discuss how to add a phone extension.

Preparing to Add a Phone Extension

Extending a phone line from one room to another is a common need for many homeowners. This wiring project can be a DIY job with proper planning and supplies.

The process involves:

  • Identifying the existing telephone wires and connectors 
  • Running new cables from the source jack to the new location
  • Splicing the wires correctly
  • Installing a new jack and testing the extended line
  • Fixing a hum in the phone line when needed.

Supplies Needed

  • Telephone wire (24 or 26 gauge, 2-conductor)
  • New telephone jack with mounting bracket
  • Wire strippers
  • Wire nuts
  • Fish tape (optional)
  • Electrical tape

Steps for Adding a Phone Line

Extending a telephone line from an existing jack to a new one in another room is relatively straightforward. Here are the steps:

  1. Turn off the house’s electricity at the breaker panel when working on telephone wiring. Never touch wires while the power is on. 
  2. Unscrew the cover plate on the existing phone jack you want to use as the origin point.
  3. Identify the color-coded wires connected to the jack. Make a note of which wire connects to each screw terminal. Red and green wires often carry the line, while yellow and black are for the phone.
  4. Get the same gauge telephone wire and a new jack for the extended line. You’ll need enough telephone cable to run from the existing jack to the new location.
  5. Disconnect the wires from the existing jack and splice them to the new telephone wire using wire nuts. Match colors — connect the red wire to the red, green to green, etc.
  6. Run the new phone line cord through the wall and ceiling to the new jack location. Use fish tape if necessary to route the wire through the finished walls. Avoid running wires parallel to electrical lines.
  7. Mount the new jack and connect the wires to the terminals in the same pattern as the existing jack.
  8. Secure the wire, replace the wall plates and covers, and test the new jack by plugging in a phone.


  • Only splice wires that are both the same gauge and type. Match solid-core to solid-core and stranded to stranded wire.
  • Staple the new wire every 4–5 feet to support and prevent sagging. But avoid over-stapling, which can damage the wire.
  • If the wire run is over 50 feet, use 24-gauge wire instead of 26-gauge for a better signal.
  • Adding a phone extension may be a good time to inspect and replace existing telephone jacks.

With care and proper technique, extending landline phones is a DIY project many homeowners can accomplish.

So, Is DIY Phone Extension Easy?

In most cases, adding a DIY telephone extension is a relatively straightforward project for a handy homeowner. The basic steps of tapping into existing lines, running new wires, installing jacks, and testing don’t require advanced skills. 

With basic preparation and safety awareness, installing phone extensions can be a weekend project. Having suitable materials and understanding your home’s wiring scheme ahead of time makes the process easier.

The main challenges are fishing wires through finished walls and routing cables over 50 feet. But even novice DIYers can figure out ‌basic phone wiring with some research. Extending jacks is also possible if you’re comfortable working around electrical systems.

So, for homeowners with basic wiring skills and DIY confidence, adding telephone outlets throughout the house does not have to be complicated. With proper technique, even complex situations can be easily managed by following codes and safety precautions.

FAQs About Telephone Line Extensions

What supplies are needed? 

You’ll need a new 2-conductor telephone wire, a new jack and cover plate, wire strippers, wire nuts, fish tape, and electrical or masking tape.

Can I tap off my Ethernet wiring? 

No, telephone and Ethernet operate on different wiring standards. You need a dedicated telephone cable for extensions.

How hard is fishing wire through finished walls? 

It depends on access — walls with limited space complicate fishing wire. Fish tape helps in pulling wires through.

What is the maximum wire run?

Fifty feet is ideal for 26-gauge wire before a signal loss occurs. Go with 24-gauge for longer runs.

Shoulf I hire a professional to add a phone extension?

If you are uncomfortable working with home electrical wiring, it may be best to hire a telephone technician, particularly for complex jobs.

Do codes apply when I install my own additional phone lines? 

Yes, NEC and local building codes apply‌ — ‌research requirements before wiring telephone extensions.

Can I extend my phone line to an outdoor location? 

Yes, with an exterior-rated jack and cable. Avoid exposing wiring to sunlight and moisture.

How do I activate a new phone line? 

Once wired correctly, the extended line should activate automatically. The phone company may need to provision additional lines.

Will extending a phone line affect my service? 

Extending one line to another room won’t impact service. Adding multiple new lines could require service upgrades, whether using a phone system for a small business, a fax machine, or a personal-use home phone number.

Editorial Contributors
avatar for Elisabeth Beauchamp

Elisabeth Beauchamp

Senior Staff Writer

Elisabeth Beauchamp is a content producer for Today’s Homeowner’s Lawn and Windows categories. She graduated from the University of North Carolina at Chapel Hill with degrees in Journalism and Linguistics. When Elisabeth isn’t writing about flowers, foliage, and fertilizer, she’s researching landscaping trends and current events in the agricultural space. Elisabeth aims to educate and equip readers with the tools they need to create a home they love.

Learn More

photo of Casey Daniel

Casey Daniel

Casey Daniel is a writer and editor with a passion for empowering readers to improve their homes and their lives. She has written and reviewed content across multiple topics, including home improvement, lawn and garden care, sustainability, and health and wellness. When she’s not reviewing articles, Casey is usually playing board games, repainting her bathroom, or quilting.

Learn More