Code Q&A
Q. I was told that a back-fed breaker needs to be bolted into the panel. Is this correct?
Code Q&A
Q. Does the NEC require a connection of a parking lot lighting pole to a ground rod?
Code Quandaries
Q. What size THHN conductor is required for a 320A 3-phase feeder load for commercial office buildings?
Code Q&A
Q. Is GFCI protection required for drinking water fountains in office buildings?
Code Q&A
Q. A 400A service is made up of two 200A main breaker panelboards that are nippled together. Can the service conductors pass through one of the cabinets to supply the other panelboard?
Code Q&A
Q. What are the NEC requirements for the installation of smoke detectors in dwelling units?
Code Q&A
Q. What are the Code requirements for bonding bushings on 277V or 480V branch and feeder and circuits?
Transformer Secondary Conductors
Similar to feeder taps, covered in the last issue, transformer secondary conductors can be every bit as confusing. Let's take a closer look at 240.21(C)
Code Q&A
Q. When PVC conduit is used, does the Code require an equipment grounding conductor between the meter enclosure and the service disconnect?
Code Q&A
Q. Section 110.14(C) requires the use of the 60°C column for 100A or less and the 75°C column for above 100A for conductor sizing. What is the value of THHN rated 90°C if the ampacity cannot be used for conductor sizing?
Feeder Taps
Sometimes, it makes sense to tap into a feeder conductor to power another conductor. From Art. 100, we know that a feeder conductor runs between service
Code Q&A
Q. Is there any allowance in the NEC to locate receptacles in dwelling units where it is convenient for furniture layout or the designer’s wishes, if the required number of receptacles is installed?
