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Overall Change
Voltage levels continue to change throughout the NEC. Question: Would the fuse on the left be suitable in a PV source circuit where 15 PV modules were wired in series, if each module had an open circuit voltage of 42 volts?
Overall Change
Voltage levels continue to change throughout the NEC. Question: Would the fuse on the left be suitable in a PV source circuit where 15 PV modules were wired in series, if each module had an open circuit voltage of 42 volts? |
Code Change Summary: A universal NEC® change to increase voltage levels occurred throughout many code articles.
Since the 1920 NEC®, the information in the beginning of most NEC® articles applied to installations of 600 volts or less and the later part of most code articles applied to installations over 600 volts.
In the 2014 NEC®, language started changing to reflect the new voltage levels in several articles but not all. In the 2017 NEC®, that movement continued to many other Articles that were not touched in the 2014 NEC®.
Making the voltage changes throughout the entire book would have resulted in a complete rewrite of some NEC® articles as well as many manufacturers going back to the drawing board to make equipment compatible with the new voltage threshold.
Now, the beginning of most articles will apply to installations of 1000 volts or less and the later part of most code articles will apply to installations over 1000 volts.
This change is due to newer technologies such as wind electrical generation systems and photovoltaic systems that can operate well over 600 volts.
2017 NEC® examples (sample only). See the actual NEC® text at NFPA.ORG for complete code sections. Once there, click on their link to free access to the 2017 NEC® edition of NFPA 70.
Article 100 Definitions.
Scope. Part I of this article contains definitions intended to apply wherever the terms are used throughout this Code. Part II contains definitions applicable to installations and equipment operating at over 1000 volts, nominal.
392.20(A) Multiconductor Cables Operating at 1000 Volts or Less.
Multiconductor cables operating at 1000 volts or less shall be permitted to be installed in the same tray.
(B) Cables Operating at Over 1000 Volts. Cables operating at over 1000 volts and those operating at 1000 volts or less installed in the same cable tray shall comply with either of the following:
(1) The cables operating at over 1000 volts are Type MC.
(2) The cables operating at over 1000 volts are separated from the cables operating at 1000 volts or less by a solid fixed barrier of a material compatible with the cable tray.
Which of the following does Part II of NEC Article 100 apply to?
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