Electrical Wiring in the Home/Guidance on 3 way switch



Need guidance on 3 way switch wiring...  See diagrams attached..   

This is the way the two switch boxes are wired.

Can't easily discover wiring in light fixture box, as it's 'up' 18 feet in a lofted ceiling, so I'm trying to figure out how this is mis-wired. It acts like a 2 1/2 switch.. depending on what position one switch is, the other works or doesn't.

Whites are pigtaled in each box, I'm not showing grounds..

Any help would be appreciated, if it comes down to looking in the light fixture box, so be it, just trying to avoid the hassle..


An 'allexpert' 3 weeks ago said to swap S5 and S6 ... which I did this weekend.. but this did not fix the problem..

With S5/S6 swapped.. I get the following matrix of whether the light is on..

left switch      right switch     result
up          up          off
up          down          off
down          up          on
down          down          off

Can you suggest how I fix this 3 way??

Hi Neil,

  Great job w/ the diagrams - pics tell a thousand stories.Looking at them - you have the standard, most common 3-way wiring layout - power in to 1st switch - run of 12/3 over to 2nd switch - then a run out to the light (if you were to access the light box - you'd more than likely find just a black / white to the black/white of the light fixture).

 However - on both diagrams, the travelers(red/black of the 12/3) are wrong.On the 1st pic - they are way off.... On the 2nd pic (labeled current) - you are closer to being right....just the travelers are crossed (they MUST be identical for proper operation)Swap the red and black on S4 and S5....and you should be in business (assuming there is no other mis-wiring on the circuit)

 I rarely ever read other experts answers (simply don't have time)....so I have no idea what he told you...but it appears he was on the right track. I know I have seen some answers at this site by so called "experts" in the past that are down right scarey..if some of those actually have an electrical license - they should be revoked.

 Hope this helps Neil....if you have new questions or still have problems...let me know. I am not online much as I am struggling to physically recover from recent open heart surgery that did NOT go well. I  will be marking myself as "away" at this site while I continue to recover to limit questions (I still get quite a few each week by email). However - you can still reach me directly by email at:


Best Wishes,

Bob Osgood
Master Electrician / Owner

Bangor, Maine  
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Master Bob


Master Electrician / Owner RKO Electric (USA Only) - can answer most of the typical residential, commercial and industrial electrical questions regarding new installations, wiring additions, lighting, switches and receptacle outlets and electrical upgrades of any nature.I will make every effort to respond to your questions as soon as possible at the end of the work day...very busy electrical company - your patience is appreciated. Stop by and see us at: www.rkoelectric.com


Licensed Master Electrician with over 34 years licensed experience - updated with the latest NEC Codes every 3 years since 1978. Over see the daily electrical operations of two electrical companies. Also serve as a judge / editor (for Electrical Contracting Products Magazine) to help select which new products are fit and safe for electricians and the electrical market.

2 Years Technical College - Degree in Electrical Construction & Maintenance (Dean's List) OSHA Safety Certified (10 & 30), CPR / Advanced First Aid Certified

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