Mike Holt

Everything You Need to Know About Switches, and More
Just like the receptacle, which was covered in this column last month, switches are a common element in everyday life. You can find them at work, in public,
Understanding the Basics of Delta Transformer Calculations 1
Transformer configuration names like and derive from the way the windings are connected inside the transformer. These connections determine the way the
Service Your Customers With the Proper Feed
How can you correctly and efficiently follow service installation requirements?
Code Q&A
Q. Does the Code permit installation of nonmetallic-sheathed cable in a three-story hotel building? A. Yes, as long as the structure is built of Type III, IV, or V construction and the cable is concealed within walls, floors, or ceilings that provide a ...
Code Q&A
Q. When does the NEC require a main breaker in a load center? A. Each lighting and appliance branch-circuit panelboard must be protected on the supply side . The overcurrent protection device can be located within the panelboard, or the panelboard’s ...
Article 406: Receptacles
You might be surprised to learn just how many rules are associated with these simple devices
Commercial Electrical Load Calculations 5
Knowing how to correctly size loads in commercial applications is an essential skill for electricians
Code Quandaries
Stumped by the Code?
Code Calculations
According to the U.S. Census Bureau, there are more than 3,500 recreational and vacation camps in this country. That's a lot of supply facility sites for recreational vehicles. Although the work may not be performed on a regular basis, do you know the ...
Code Q&A
Q. I don’t see where 300.4 limits the number of NM cables through a given opening in wood or metal framing members. I don’t want to turn the framing members into Swiss cheese and reduce their structural integrity by boring a hole for every NM cable. So ...
Keep Your Cool When Working With A/C and Refrigeration Equipment 1
Demand for knowledge of Art. 440 requirements is heating up
Code Q&A
Q. Is GFCI protection required for a hard-wired spa? A. GFCI protection is required for both cord-and-plug and hard-wired spas containing single-phase equipment . GFCI protection isn't required for the outlet that supplies a spa that has integral GFCI ...
Clearing Up Multi-Family Dwelling Unit Calculations
Calculating multi-family dwelling unit service sizes needn’t be a difficult process, but it can be if you don’t follow the right steps
Code Quandaries
Stumped by the Code?
Code Calculations
When installing conductors of different sizes (or types of insulation) in a raceway, you can’t size the raceway based on Tables 1 through 12 in Annex C. You must instead follow this three-step process to determine the proper raceway and nipple size ...
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