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Missing knock out plug, no big deal… maybe?

Reblogger John Anello, Stamford Area Electrician
Home Builder with Safe and Sound Electric LLC E1-125403

A missing knock out blank is one of the most common electrical problems I see in homes. I see it all the time, and try to correct it. Donald Hester wrote a great article about why this situation can cause problems.

Original content by Donald Hester

Missing knock out plug, no big deal… maybe?    Wenatchee and Quincy Home Inspection Services

Ah another tale from the traveling home inspector.

One of the things we do is to provide safety information. Many times people think it may be not that important or relevant. And for them it may not be. We all live with risk on a daily basis.

On this particular home inspection I was letting my client know that the electrical panel was missing some knock-outs in the panel and that they should have proper plugs installed.

                                 missing knock out plugs Wenatchee Home Inspection

The reason for this is twofold. One we want to prevent entry by insects, rodents and debris into the panel and two if a fire starts in the panel we want to contain it in the service panel.

Here is a perfect example of why this may come into play. A home in Florida was completely engulfed from an electrical fire that started in the panel.

                             Fire damage from electrical panel Florida Home Inspection Team

                                  (Photo courtesy of Bill Siegel - The Florida Home Inspection Team)

Per Bill Siegel of The Florida Home Inspection Team-

(Why the house burned) “This is a result of a missing knock out (as determined by the insurance adjuster). There was a missing plug on the fuse panel. A fire started inside the box. Because the box was not enclosed the flames jumped out of the box and ignited something nearby and this is the end result.

That one little plug may not have prevented this from happening, but it might have slowed it down and minimized some of the damage.”

                                                         Electrical knockout plug Quincy Home Inspection

In most situations this will never come into play but like many safety items we want them to be there when needed.  Sometime the simplest of devices can prevent a major catastrophe.

Ancora Imparo


NCW Home Inspections, LLC  is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…  

Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service

www.ncwhomeinspections.com                                               509-670-9572

Larry Johnston
Broker, Friends & Neighbors Real Estate and Elkhart County Subdivisions, LLC - Elkhart, IN
Broker,Friends & Neighbors Real Estate, Elkhart,IN

Hi John, That is a good thing to know.  Thanks for informing us.  Have a great day.

Jan 28, 2014 10:02 AM
Connie Harvey
Pilkerton Realtors - Brentwood, TN
Realtor - Nashville TN Real Estate

John, I know nothing about electricity but that it needs to be done correctly. They did an inspection on my dad's house a couple of weeks ago and had some electrical stuff in the panel that they wanted fixed. I didn't argue. Told my guy to make it safe for the next owner!

Jan 29, 2014 12:32 AM
Rod Pierson
Wilson Realty Inc - Redding, CA
Northern California - An Agent you can trust

John,   Usually a sign of an unlicensed electrician or home owner not following up with an inspection.   In the photos there is no reason to leave two inch knock outs not being properly covered.    I like using the three piece knock out plug.  The snap ins are ok for 1/2 - 1 inch anything larger the three piece knock out should be used.   Great post. 

Jan 29, 2014 01:54 PM
Grant Schneider
Performance Development Strategies - Armonk, NY
Your Coach Helping You Create Successful Outcomes

John - That is why it pays to have work done by licensed electricians as well as other licenced professionals.

Jan 30, 2014 09:27 PM
Tom Braatz Waukesha County Real Estate 262-377-1459
Coldwell Banker - Oconomowoc, WI
Waukesha County Realtor Real Estate agent. SOLD!

John Anello

 This is really good advice for me to pass on to my clients

Oct 25, 2014 05:00 AM
Rod Pierson
Wilson Realty Inc - Redding, CA
Northern California - An Agent you can trust

Who would know a fifty cent part eliminated could lead to
Many thousands of dollars of damage?

No different than a fifty cent freeze plug which could leave you stranded and worse freeze your motor.

After forty years of electrical service work I have seen so many electrical violations waiting for a fire. I trained those who have worked for me to look for many simple items that can be overlooked and repair as necessary, we always had knock out seals of all sizes to make that simple repair.

Circuit breakers removed and or a home owner knocking out the wrong metal knock leaves another dangerous situation which could lead to a dangerous shock.

Always request an experienced home inspector and possibly an inspector who has been a electrical or general contractor.

Great post and I hope you welcome my comments.

Oct 26, 2014 05:22 PM