Fine Print Notes

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swen

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Article 215.2(A)(3) FPN No. 2 discusses excessive voltage dropes in branch and feeder circuits. Fine Print Notes are not mandatory. Does the NEC require that conductor sizes be increased if the voltage drope in a branch circuit becomes more than 3 pecent or the voltage drop in a branch plus a feeder becomes more than 5 percent?
 
No, it does not require that. Good engineering practice would, and the client might have something to say on the topic, but not the NEC.

Welcome to the forum.
 
See 90.5(C) Explanatory Material.



The NEC is a safety document.

Design issues generally fall on the designer, which may necessitate exceeding the minimum requirements of the NEC.

I have always wondered why they never made it mandatory since it can be a safety problem, if the voltage drop is enough it can keep the OCPD from opening, especially in a 430 install?:confused:

I could see a 10% being a mandatory limit, that would still provide OCPDs safety?
 
In Subsection 8.2.1, ASHRAE 90.1 requires that feeder and branch-circuit voltage drop not exceed 2 percent and 3 percent, respectively.
This is the energy code reference if your adopted energy code has incorparated the ASHRAE Standard.
I do not think that the IECC has it on its own.
 
I have always wondered why they never made it mandatory since it can be a safety problem, if the voltage drop is enough it can keep the OCPD from opening, especially in a 430 install?:confused:

I could see a 10% being a mandatory limit, that would still provide OCPDs safety?


I thought overcurrent devices worked strictly off current ?
 
NEC only limits voltage drop in Fire Pump motor feeders. (and welding feeders as I recall but it's been a while. :) )
 
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