Code Clusters is a fond look back at some of the most interesting and outlandish Code violations published in the pages of EC&M magazine over the past 15 years — the item below is the fourth in a series of 10. Questions? Comments? We'd love to hear your feedback! Post your thoughts in the box below.
Homemade Fuses Create Recipe for Disaster
All references based on the 2005 edition of the NEC.
Derek Thomas, an eight-year journeyman electrician, ran across this installation in a mechanical loft of a new church while working for Classic Electric and Design in Plymouth Meeting, Pa. “The disconnect was feeding heating elements in air handlers,” said Thomas.
How did they get there? “Over a long Thanksgiving weekend the temperature dropped, and one of the subcontractors was screaming for heat. The HVAC contractor came in when we were not there and improvised to get the units running,” said Thomas.
The person who installed these so-called “thinwall fuses” obviously had no regard for human life or property. An overcurrent condition on this system would most likely lead to a horrible ending.
Article 240, Part VI outlines the requirements for a safe installation of cartridge fuses and fuseholders. General marking rules for fuses can be found in 240.60(C).