Electrical Wiring in the Home/Running Romex Thru Sub-Floor


Romex at vent pipe
Romex at vent pipe  
Hi Bob,

Can I run my romex along/through the sub-floor opening that my 2" plumbing vent runs through?  

The opening is more than ample to run 3 lines I need through the sub-floor.     

I'm trying to avoid drilling yet another hole through the sill plate in an area that already has 3 existing holes for plumbing, but certainly I want to do whats right.

THANKS IN ADVANCE for any advice!

Hi Ron,

   Based on the picture you posted - yes you should be able to run the 3 lines thru that opening where it is only a vent pipe and has plenty of space (we do it all the time in  remodels and it always passes rough-in inspection). However - if the romex is closer than 1.25 inches to the wall edge of the wooden member - that you must use a steel nailer plate (usually 1/16 inch thick) to cover that area to avoid damage from a nail or screw - I can't tell from your picture how close the romex is to the edge - but if it can be moved back closer to the center of the wall and supported  so it will not get closer to the edge - a nailer plate will not be required (see Art 300.4 of the 2011 NEC )

  Also - where these are "open" walls - all the romex runs must be supported and secured (as opposed to wires fished thru the hollow of finished walls which are allowed to free fly inside the wall)- if the romex I'm seeing coming up thru a bored hole in the wood was pre-existing and there for too short to be stapled to or otherwise secured to the sides of the studs - your local inspector may allow it...some will...some won't.

 Hope this helps Ron...if you have more questions - please follow-up. NOTE: due to recent open heart surgery (that did not go well)...I will be marking myself as "away" at this site to limit questions until I recover further.You can still reach me by email with any follow-ups at:


Best Wishes,

Bob Osgood

Owner / Master Electrician

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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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