ramon1
New member
- Location
- perris, ca,
I was just wandering if voltage drop is a requirement per the NEC because I cant find it but, I thought it was. Can someone please help? thanks
Not so fast there my friend. Take a look at 647.4 (D) limits voltage drop to 1.5%. Just poking some fun at you Roger.No, it is not an NEC requirement.
Other than 647 applications I am not aware of any maximum voltage drop requirements. However you will see notes suggesting 5% max, but not required.
Not so fast there my friend. Take a look at 647.4 (D) limits voltage drop to 1.5%. Just poking some fun at you Roger.
695 - Fire Pumps, also has a voltage drop requirement.
You guys are right, I was only thinking in terms of general wiring applications.
Roger
and calif. is now dealing with title 24, 2013 flavor, and i do
believe that voltage drop is now a part of *that*.
the ashrae 90.1 thing, as ron said.
my EE is having fits about it. the feeder calcs are killing him.
what used to be a 5% total voltage drop, 2% feeders, 3%
branch circuits, with the option of doing 3% feeders, 2%
branch circuit drops, is now 2% feeders, period.
What I want to know is when we are dealing with these VD requirements what exact value do we start the VD calculation at and how is monitored to be sure it stays at that number continuously?
220.5 is part of the NEC which doesn't mandate a VD limit, (besides the aformentioned article sections).220.5 says to use the nominal voltage to start.
Roger I was just poking some fun at you. Hope you were not offended as none was intended.You guys are right, I was only thinking in terms of general wiring applications.
This reminds me to buy some more Freeport McMoRan stock for the portfolio.and calif. is now dealing with title 24, 2013 flavor, and i do
believe that voltage drop is now a part of *that*.
the ashrae 90.1 thing, as ron said.
my EE is having fits about it. the feeder calcs are killing him.
what used to be a 5% total voltage drop, 2% feeders, 3%
branch circuits, with the option of doing 3% feeders, 2%
branch circuit drops, is now 2% feeders, period.
Dereck, not offended at all. I actually expected to be called on it.Roger I was just poking some fun at you. Hope you were not offended as none was intended.
Well, one reason is that although the load causing the VD will work well with either spec, other loads seeing same VD will notice the difference. The voltage change will be noticeable in non- regulated lighting, some motor speeds, etcMy point is, why not just state a minimum voltage for each system voltage and be done with it?
Roger
My point is not about specific loads and their affects or what is the cause of the VD, my point is 5% is 5%, Start at any of the nominal voltages in 220.5 and do the math, now this number can be set in stone as a minimum for each system voltage.Well, one reason is that although the load causing the VD will work well with either spec, other loads seeing same VD will notice the difference. The voltage change will be noticeable in non- regulated lighting, some motor speeds, etc
This is also a reason for being more strict about service and feeder drop than branch drop.
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So why try to put a VD percentage on a system voltage across the board?But it does not generalize to all VD situations.
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