Why is a strain relief clamp necessary for the cord connection to some electric appliances?

Tuesday, June 26, 2018

Appliances like a kitchen disposal and water heater do not come with a power cord installed by the manufacturer because they can be either hard-wired through conduit to an electrical box or utilize a power cord to connect to a receptacle. Clothes dryers do not have a power cord already installed because the homeowner has to match the number of prongs at the end of the cord to the slots in their dryer receptacle at home: either an older-style 3-slot receptacle or a newer 4-slot receptacle. So the cord is purchased separately. 

    When a power cord is connected to terminals inside the appliance, the point where the cord penetrates the shell of the appliance needs to have a strain relief clamp, also sometimes called a cord connector, as a securing device. It attaches to the opening (knockout) and snugs down around the cord to do two things:

  1. Keep the wire connections of the cord inside the appliance from coming loose if the cord is tugged.
  2. The rounded edges at the outside of the clamp keep the edge of the casing from cutting into the cord sheathing from any back-and-forth movement of the cord.

    Here’s three examples below of missing strain relief clamp locations we find during a typical home inspection.


    And here’s a strain relief clamp correctly installed at the back of a dryer.

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Here’s links to a collection of some of our other blog posts about APPLIANCES: 

What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?

Which house appliances need a dedicated electrical circuit? 

Is a washing machine drain hose required to be secured at the standpipe?

When was GFCI-protection for kitchen dishwasher receptacle outlet first required? 

Why does venting a clothes dryer into a garage, attic, or crawl space cause problems?

Does a refrigerator water supply line require a shutoff valve behind it? 

My spa tub stopped working. What's wrong?

What is the maximum recommended height above the floor for an above-the-range microwave?

Why would a home have natural gas appliaces but no gas meter? 

Is a hot water faucet required at a washing machine?

Can I remove a 240-volt range receptacle and hard-wire the range? 

 Can a dishwasher be wired to a kitchen counter small appliance receptacle circuit?

Why is it bad to have a clothes dryer vent near an air conditioning condenser (outdoor unit)? 

Do home inspectors test the appliances?

What are the most common defects with over-the-range microwaves?

Are a range and refrigerator required kitchen appliances for a house to pass FHA inspection? 

What are the code requirements for an outdoor dryer vent cover?

What is the maximum length for a clothes dryer vent? 

Why are my ceiling fan blades drooping?

How do you inspect a dryer vent? 

• Why is there a water hose connected to the back of the clothes dryer?

    Visit our ELECTRICAL and APPLIANCES pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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