BEFORE THE ARCHITECT – E-PUBLICATIONS
Home Design Standards-Home Building Standards
Electrical Design Standards
Home Design Standards – Home Building Standards, 3Q10 Ed. Page 386
ii) including no interconnection whatsoever between a grounded conductor and a grounding conductor in a electrical distribution panel board, sub panel, junction box, electrical device, etc.
iii) including no interconnection whatsoever between grounded conductors
Comment: Sorry for all those shall nots; however, this home designer needs to close the loopholes. Interconnecting grounded conductors is especially a condition this home designer’s seen in commercial and industrial electrical wiring, along with several hot legs each relying on the same grounded conductor.
Tragic consequences can come calling from these so-called “dirty neutrals”: AFCIs and GFCIs won’t work as designed with interconnected grounded conductors; electrical loading up a grounded conductor with several energized conductors can overheat the grounded conductor.
2) Each electrical circuit wiring electrical load
a) shall be judged as to whether it is continuous if
i) it could reasonably supply continuously for 3 hours or more or
ii) de facto, as in an electrical water heater of 120 gallon capacity or less
iii) if daylight = 0%
iv) if there are no windows in the load space
b) if judged continuous, then it shall be derated by 20% (, or the peak electrical load multiplied by 1.25, please see NEC2006 422.1) subsequent to all other deratings
Comment: Usually, any given residential electrical load is not regarded as continuous. Continuous electrical loads come into active play in commercial and industrial applications. However, the AG knows full well that some electrical loads in a residence can operate frequently well beyond 3 hours continuously, e.g., some exterior home light and some interiors home light, entertainment centers, computer equipment, attic fans, etc.
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