Voltage drop

[ramsy]

Ramsey as complicated as you like to make this the NEC does not control voltage drop except in the two Sections I posted.

Then we agree, NEC liberty with voltage drop never permited mixing Nominal voltages, or violating listings, much less local codes and job specs.

Your allowed 100% voltage drop unless there is a local code that says otherwise.

Anyone advocating 100% v-drops for general purposes --as an NEC liberty-- should be spanked, at least by equipment listings, if not publicly flogged with vegetables and other nearby rubbish. Should the need arise, I'll be happy to provide more spankage. :twisted:

Again you want to write a novel thankfully you do not write code sections, the NEC would be ten volumes :lol:

If I proposed novels of code I believe you would read every line, and your engagement at every point would be my pleasure. :twisted:

 

[iwire]

Roger nice post :lol:

I am glad your on the left coast so you can not spank me.

Of course you would not have to as I do wire to avoid voltage drop.

Today was the first day at a new job, it is a medium large store and the plans specify 10 AWG minimum for all circuits unless otherwise noted. 8)

 

[marinesgt0411]

Why not just look at the chart that came with the transformer that tells you what wire size to use for what length and which tap to connect to

 

[iwire]

Why not just look at the chart that came with the transformer that tells you what wire size to use for what length and which tap to connect to

Oh sure go the easy way. :lol:


Actually that is probably the best answer in this thread. 8)

 

[coulter]

So are 460V motors on 480V okay? How about 200V motors on 208V?

Yes, 3 phase.

carl

 

[iwire]

Yes, I see. Mike Holt's 99 NEC guide book also shows the code violation if equip. rated 208vac is installed on a 240vac nominal circuit, regardless of voltage sags. 240vac equip. on 208 nomimal is not addressed here.

Roger here is a bunch of info from Mike Holt about voltage drop, the NEC and hazards.

http://www.mikeholt.com/technical.php?id=technicalvoltagedrop

I get the impression that Mike's of the opinion that the NEC can not be used to enforce VD restrictions other than when directly referenced. (My words, not his)

 

[ramsy]

Roger here is a bunch of info from Mike Holt about voltage drop, the NEC and hazards. http://www.mikeholt.com/technical.php?id=technicalvoltagedrop

Nice link on ShureTest v-drop issues, use of 110.3(b), v-drop hazards, etc..

In "Voltages [110-4]" where Mike Holt[/url]]"..and, in addition, electrical equipment must not be connected to a nominal voltage source that is less than the equipment rated [110-3(b)]"

it also seems using 110.3(b) here implies that 110.4 is not needed, if equip. labels prohibit mixing Nominals anyway.

Whether your AHJ agrees with Mike or not, I think we agree that the NEC does not generally enforce v-drop, until it violates other codes. And, that embracing the virtues of a Target Voltage calculator using impedance limits, complies with the NEC either way.

 

[iwire]

Nice link on ShureTest v-drop issues, use of 110.3(b), v-drop hazards, etc..

Or lack of hazards.

that embracing the virtues of a Target Voltage calculator using impedance limits, complies with the NEC either way.

Sure but not required and I have no intention of becoming an electrical engineer. 8)

(No offense to our fine engineers here 8) )

 

[ramsy]

Sure but not required and I have no intention of becoming an electrical engineer. 8) (No offense to our fine engineers here 8) )

Yes, the Target Voltage calc. meets other requirements. NEC 110.10 requires impedance(Z) & ASCC (E/Z) to be "selected and coordinated" with OCPD, trip times, & with other component listings. Do you concern yourself with this stuff, or have a simpler way of doing it without Z?

Everthing seems to fall in place when conductor lengths match Table 8 or 9 near 0.25 Ohm. But, when material budgets are cut, or V-drop, Z, & ASCC formulas are needed, the Target Voltage calc. may be the simpler way to check most of these variables.