Why is bundled wiring in an electric panel a defect?

Tuesday, July 10, 2018

Neat and organized wiring is one of the ways you can tell that an electric panel was wired by a professional electrician. Wires from breakers on the right side of the panel exit the box on the same side. They don’t cross over the service cables or run around the bottom. This requires planning and careful execution, and the completed work sometimes resembles a wiring diagram, with each wire turning at a right angle next to the breaker before it heads up or down and out of the box.

     A good electrician is justifiably proud of a well-organized panel. But bundling the wires together with zip-ties to further enhance the organization of the panel, like in the photo above, is a step too far. Both the wiring and breakers in a panel generate heat and air space around the components is needed for heat dissipation. When the wires are bundled, heat generated by the inner wires is trapped by the surrounding ones. Also, each wire connected to a breaker helps to conduct heat away from the breaker, but this is nullified if the wire runs into a bundle just an inch away from the circuit breaker terminal.

    The National Electric Code does not directly ban bundling in a panel but does require adjusting wire size (derating) for bundled wiring 24-inches or more in length as a way to avoid overheating. Because many wires converge and heat is concentrated in an electric panel, even if the length does not exceed 24-inches, bundling is still the wrong thing to do. 

    Also, see our blog post Why do some wires in an electric panel have tape wrapped around them near their connections?

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Here’s links to a collection of our other blog posts about ELECTRIC PANELS:

What causes copper wires to turn green or black in an electric panel?  

What is the maximum number of circuit breakers allowed in an electric panel?

When should a corroded or damaged electric panel cabinet or disconnect box be replaced? 

What is a tandem circuit breaker? 

When did arc fault circuit interrupter (AFCI) breakers first become required?

Can an electric panel be located in a closet? 

Can an electric panel be located in a bathroom? 

Can you add circuit breakers by different manufacturers to an electric panel if they fit?

My circuit breaker won't reset. What's wrong?  

What is a split bus electric panel?

How do I identify a combination AFCI (CAFCI) circuit breaker? 

What does a circuit breaker with a yellow or white test button indicate? 

What is the maximum gap allowed between the front of a recessed electric panel box and the wall surface surrounding it? 

What are the requirements for NM-cables entering an electric panel box?

Why is a fuse box/panel an insurance problem for homebuyers? 

Why is bundled wiring in an electric panel a defect?

What is the difference between GFCI and AFCI circuit breakers? 

Why are old electrical components not always "grandfathered" as acceptable by home inspectors?

What happens when you press the "TEST" button on a circuit breaker in an electric panel?

What is a Dual Function Circuit Interrupter (DFCI)? 

What is the difference between a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?  

What is the difference between "grounded" and "grounding" electrical conductors? 

What does it mean when a wire is "overstripped" at a circuit breaker?

Why is an old fuse panel dangerous?  

Who is the manufacturer of those "bad" electric panels?

Why is the circuit breaker stuck in the middle? 

What is a double tap at a circuit breaker?

What is the right electric wire size for a circuit breaker in an electric panel?

What is the life expectancy of a circuit breaker? 

My circuit breaker won't reset. What's wrong? 

Why do some breakers in my electric panel have a "TEST" button on them?

What is the right size electric panel for a house? 

• What do I need to know about buying a whole house surge protector? 

What is the maximum allowed height of a circuit breaker (OCPD) above the floor?

• What is the maximum height you can mount an electric panel above the floor? 

• What is the code required clearance in front of an electric panel?

What is the main bonding jumper and where do it find it in an electric panel? 

   Visit our ELECTRIC PANELS page 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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