Mike Holt

Code Quandaries
Q. I have a 1,200A, 480V panel that has a working space of 3½ feet. The engineer says 7 feet is required. Is he correct?
Code Q&A
Q. We have motors that are interlocked, preventing them from being on at the same time. Do we still have to add them up for service and feeder calculations?
Code Q&A
Q. Is a disconnect required to be within sight of electric space-heating equipment if the unit has a factory-installed circuit breaker?
Code Quandaries | September 2008
Q. What are the requirements for installing fixtures in a bathroom?
Motor Calculations 4
To prevent a motor from burning up, you must provide a means of protecting it from overcurrent (overload, short circuit, or ground fault). If you can remember not to confuse motor protection with circuit protection, you’ll eliminate a major point of confusion in motor calculations.
Code Q&A
Q. What is the smallest size wire you can use for a lighting fixture whip?
Stumped by the Code?
Q. Am I required to secure Type MC cable that is located under a raised floor of an information technology equipment room?
Fill Er Up
Raceways must be large enough to hold conductors without overheating and avoid insulation damage during conductor pulls. Therefore, we must determine the maximum number and size of conductors to put in a given raceway. That limit is what we mean by raceway fill.
Code Q&A 1
Q. What is the maximum number of bathroom receptacles that can be placed on the 20A, 120V bathroom receptacle circuit in a single-family dwelling?
Conductor Size Matters
The NEC provides minimum size requirements for conductors to prevent overheating and fire.
Code Quandaries | August 2008
Q. When adjusting the ampacity of a conductor due to conductor bundling, do we use the 90°C column ampacity or the 75°C column ampacity as listed in Table 310.16 for THHN?
Code Q&A
Q. Is the required working space for a panel measured from the panel guts inside the panel or from the panel cover?
Code Q&A
Q. What are the requirements when installing a 120V switch in the same box with a 277V switch?
Code Q&A
Q. Can I use 14 AWG conductor pigtails from a 12 AWG, 20A circuit so that I can backstab the wires to the receptacle?
Code Q&A
Q. I have a building that has two services from the utility. Do I have to use the same grounding system for both?

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