FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

I’m trying to diagnose a 3-way switch

| Posted in General Discussion on June 26, 2008 07:27am

My client has a weird electrical setup that some shmoe installed. It seems as though I’ve spent my entire life fixing some other guy’s mistakes. Power was going out in a bathroom unexpectedly (never mind that the owner and tenant share this circuit) I finally found an old three way in the back of a closet that somehow controls the circuit and has accidentally flipped by the owner, Problem is, there seems to be no accompanying three way anywhere else. More oddly, the switch and all three wires are not energized when it is on and providing power, but shows current when it is off. Huh?

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. DanH | Jun 26, 2008 08:12pm | #1

    How old is this structure? Any old knob-and-tube wiring?

    It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
    1. 38669227 | Jun 26, 2008 09:07pm | #3

      I'd say it was built in the 40's, maybe later. No evidence of K&T. Neutral reversed? Hmm. How could I diagnose that? Where is the other switch? Isn't that required to make it work a all? I'm thinking that this clown must've buried it somewhere...

      1. DanH | Jun 26, 2008 09:30pm | #5

        There was a style of wiring a 3-way, now illegal but popular with K&T, where the two switches are set on opposite sides of the fixture, with each switch choosing between hot and neutral, the commons feeding the fixture.
        It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May

        1. 38669227 | Jun 26, 2008 09:39pm | #6

          Oh yeah! That was called the Carter system I think. The polarity may be reversed. So the neutral is carrying the load? That's why I detect no current at the switch when it's on? Jeez! Sounds like I may be opening walls to fix this. It'll be really hard to explain this situation to my client when for all intensive purposes, it appears to be working. Do you think I should just leave it be?

          1. DanH | Jun 26, 2008 09:41pm | #7

            I'd recommend removing the switch, wire-nutting together the two wires that need to be connected, and installing a blank cover. Or just tape over the switch with several pieces of duct tape.
            It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May

          2. 38669227 | Jun 26, 2008 09:45pm | #8

            That sounds like the plan to me. I'll just make sure that the fixtures and receptacles all have correct polarity, Thanks!

  2. USAnigel | Jun 26, 2008 08:51pm | #2

    Sounds like the neutral is getting switched.

  3. User avater
    BillHartmann | Jun 26, 2008 09:13pm | #4

    "More oddly, the switch and all three wires are not energized when it is on and providing power, but shows current when it is off. Huh?"

    EXACTLY what does that mean.

    What use used to make the measurements and exactly how where they done.

    What wires and cables are in that box and how are they connected.

    All applications for a SPDT switch are not for use as 3-way switches. They can be used to select one of 2 options. Examples are for a 2 speed fan and an outdoor light that can be swtiched to automatic (photocell or timer) or manually on.

    .
    .
    A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
  4. User avater
    Mongo | Jun 27, 2008 03:33am | #9

    You've written a couple of times that there is no current when the switch is ON, but there is when the switch is OFF.

    When you write ON do you mean the switch is in the "up" position, and OFF it's in the "down" position? Remember, if this is a 3-way, ON/OFF and up/down are only relative depending on the orientation of the other switch.

    1. 38669227 | Jun 27, 2008 03:59am | #10

      Actually, what I mean to say is that the fixtures and receptacles are energized but the 3-way itself has no current flowing through any of the three wires. When the switch is flipped the lights etc. go off and at least one of the wires in the switch becomes energized. Crazy?

      1. DanH | Jun 27, 2008 04:24am | #11

        You mean no voltage registers, I suspect. Unless you have a clamp-on ammeter you can't measure current.
        It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May

        1. 38669227 | Jun 27, 2008 04:37am | #12

          Right, no voltage detected with a reliable non-contact tester. I had no voltage detected with the wires disconnected and using a multimeter.

  5. bobbys | Jun 27, 2008 06:43am | #13

    Dont know but i did wire a 3 way that did not work .

    I had an electrician come over and look at it.
    I had wired it correctly but the switch was bad

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

FHB Summit 2025 — Design, Build, Business

Join some of the most experienced and recognized building professionals for two days of presentations, panel discussions, networking, and more.

Featured Video

A Modern California Home Wrapped in Rockwool Insulation for Energy Efficiency and Fire Resistance

The designer and builder of the 2018 Fine Homebuilding House detail why they chose mineral-wool batts and high-density boards for all of their insulation needs.

Related Stories

  • Guest Suite With a Garden House
  • Podcast Episode 688: Obstructed Ridge Vent, Buying Fixer-Uppers, and Flashing Ledgers
  • FHB Podcast Segment: Finding the Right Fixer-Upper
  • Keeping It Cottage-Sized

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data