210.6 Branch-Circuit Voltage Limitations. The nominal voltage of branch circuits shall not exceed the values permitted by 210.6(A) through 210.6(B).
(A) Voltage Limitations. In dwelling units the voltage shall not exceed 120 volts, nominal, between conductors that supply the terminals of the following: (1) Luminaires (lighting fixtures) (2) Cord-and-plug-connected loads 1440 volt-amperes, nominal, or less or less than 1⁄4 hp (B) 120 Volts Between Conductors. Circuits not exceeding 120 volts, nominal, between conductors shall be permitted to supply the following: (1) The terminals of lampholders applied within their voltage ratings (2) Auxiliary equipment of electric-discharge lamps (3) Cord-and-plug-connected or permanently connected utilization equipment
Joe Tedesco, NEC Consultant
Re: Suggested Proposals for the 2008 NEC#93207 05/10/0501:36 PM05/10/0501:36 PM
Neither (A) nor (B) (because they refer to 120 volts between conductors) permits circuits or loads with 240 volts between conductors (120 volts to ground). So that leaves (C) as the only means to permit that. Leaving out (C) would thus be making those circuits not legal.
Additionally, some very large homes do have higher voltages. I've heard of a few being supplied 480Y/277 by the utility (obviously reducing it down to 120 volts to ground with a transformer for the majority of branch circuits), and tapping the 480 for a few things, such as large water heater systems (25 kW and up). Is there a good reason to restrict these to 240 or 208 volts?
Also, if this is going into a new article just for dwelling units, why not just merge (A) and (B) together? They only seem to be separate now so (A) can apply only to dwellings while (B) applies everywhere.
[This message has been edited by pdh (edited 05-10-2005).]
Re: Suggested Proposals for the 2008 NEC#93210 05/12/0510:57 AM05/12/0510:57 AM
Joe Are you supporting the change that would replace the term equipment grounding with equipment bonding? Will the term ground fault be simplified to fault with a definition of fault as unintended contact between current carrying conductors and non current carrying conductive elements of the structure? -- Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison
Re: Suggested Proposals for the 2008 NEC#93212 05/15/0504:05 AM05/15/0504:05 AM