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McGarry and Madsen's home inspection blog for buyers of  

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Can a doorbell transformer be installed inside an electric panel?

Saturday, June 30, 2018

The National Electrical Code (NEC 725.136A) specifically excludes any low voltage wiring from being installed in an electric panel, raceway, or box used for high voltage (120/240V) circuits. Electricians know better, but we regularly find homeowner-installed doorbell transformers sitting loose in the bottom of an electric panel, like in the photo above. This particular homeowner also attached flammable paper tags to the wiring to each breaker to identify the circuits—another no-no.

    It is acceptable, however, to mount the doorbell transformer to the exterior of a surface mounted electric panel, and is usually done at the top of the panel. Also, see our blog post Is a doorbell required by code for a house? and Can a home surge protector be installed loose in the bottom of an electrical panel box? 

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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?

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?

• When is an electrical panel overcrowded with too much wiring?

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 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 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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