ramsy said:
iwire said:
Your allowed 100% voltage drop unless there is a local code that says otherwise.
Bob, you better move that one decimal to the left. 120v-108v=12 or 10%
No, I will stick with my original answer. 8)
By your interpretation dimmers, Soft-starts, VFDs etc would all be unacceptable.
ramsy said:
AHJ's don't need v-drop rules to fail branch voltages. If the equipment has a nameplate or otherwise lists a voltage, these listings are enforceable: NEC 100.4, 110.3(B), or 100 Voltage, Nominal "..within a range that permits satisfactory operation of equipment."
Lets look at your code references.
Article 100's "Voltage Nominal" is just a definition, it is not a code section or directly enforceable.
I assume 100.4 was meant to be 110.4
110.4 Voltages.
Throughout this Code, the voltage considered shall be that at which the circuit operates. The voltage rating of electrical equipment shall not be less than the nominal voltage of a circuit to which it is connected.
Notice that if you read this section it prevents over voltage to the equipment it does
not prevent under voltage to equipment.
110.3(B)
(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
True enough, if you can find a
minimum voltage included in the listing or labeling than you may be onto something.
However just because a piece of equipment is tagged 120 volts does not mean suppling it with 50 volts is violation anymore than a suppling it with 119.9 volts.
I am well aware of ANSI C84.1, it is not a code, it is a standard which unless there is a local rule otherwise is unenforceable.
(Many power companies are required to follow ANSI C84.1 by the local power commissions etc.)
I have real doubts that you will find any electrical inspectors enforcing ANSI C84.1.
But lets keep in mind in this thread we are talking about incandescent lamps here and they are designed to run from 0 to 100% of their 'nameplate'.
ramsy said:
For 120vac systems, the unavoidable-equipment nameplates found in most inside wiring, include computer, printer, copier, fax, monitor, TV, and other rectified power supplies.
My Dell PC has says it can run fine with voltages from 90 to 136 volts without changing any settings.
I would say, NEC rules do regulate voltage drop indirectly, but industry-diverse NEC panel members have historically confined voltage drop complexity to FPN's, perhaps accurately anticipating misapplication by a well represented fraction of authorities having jurisdiction (AHJ).
We will have to agree to disagree on the NEC regulating voltage drop indirectly.
IMO the reason the NEC has not moved the FPNs to code is simple.
It is not an electrical hazard assuming the rest of the NEC is followed and is outside the stated purpose of the NEC.
90.1 Purpose.
(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance will result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.
As a final comment I point out that there are a couple spots in the NEC that do
directly control voltage drop.
687.4
695.7
If 110.3(B) could be used to control voltage drop than these sections along with the FPNs where unneeded.
Bob