# current or no current



## McClary’s Electrical (Feb 21, 2009)

Those numbers calculated into a voltage drop calculation give me a 65% voltags drop down to 77 volts. It sounds as if he didn't.do any calculations. Did you give him fhe motor specs before he started?


----------



## johnnyd_is (Jun 5, 2012)

mcclary's electrical said:


> Those numbers calculated into a voltage drop calculation give me a 65% voltags drop down to 77 volts. It sounds as if he didn't.do any calculations. Did you give him fhe motor specs before he started?


no body knew exact but what gets me is after i told him not enough power he said i was full of crap


----------



## varmit (Apr 19, 2009)

There are WAY too many folks that can run pipe and pull wire, but can't do basic calculations related to their trade.


----------



## McClary’s Electrical (Feb 21, 2009)

johnnyd_is said:


> no body knew exact but what gets me is after i told him not enough power he said i was full of crap


 
If you didn't tell him what the calculated load was on the circuit, who told him what to run? 

By the way, there are no NEC codes madating voltage drop. So, to be honest, it sounds like you're stuck. Unless you gave hime the calculated load on the circuit, and then explained to him that you need a circuit with less than 5% voltage drop, you got what you asked for. Pay him for what he did, and then pay him to re-do it. Lesson learned. If I were him, in this situation, you would owe me for what I just did and running a new circuit


----------



## McClary’s Electrical (Feb 21, 2009)

johnnyd_is said:


> no body knew exact but what gets me is after i told him not enough power he said i was full of crap


 
That's because you're trying to pin something on him that's not his fault.


----------



## johnnyd_is (Jun 5, 2012)

no no no what im saying is HE says im wrong he says my motor is faulty! i told him no its to small wire nobodys at fault yet it was a building take over and no one knew what was there in the first place we are all on the same team my point is simply RUN VS LOAD me telling him what i need he still says im wrong


----------



## McClary’s Electrical (Feb 21, 2009)

johnnyd_is said:


> no no no what im saying is HE says im wrong he says my motor is faulty! i told him no its to small wire nobodys at fault yet it was a building take over and no one knew what was there in the first place we are all on the same team my point is simply RUN VS LOAD me telling him what i need he still says im wrong


 

Oh, you're 100% right in your findings. And by my voltage drop calculation, my numbers closely match yours. 

By the way, in order to stay within NEC guidelines (not a mandated code) you could only put 5 amps of load on a # 12 @ 310 feet one way measurement.


----------



## johnnyd_is (Jun 5, 2012)

going to my original question as to how can i explain to the electrician why this dosnt work? when he said it should?


----------



## McClary’s Electrical (Feb 21, 2009)

johnnyd_is said:


> going to my original question as to how can i explain to the electrician why this dosnt work? when he said it should?


 

Tell him to show you his voltage drop calculations. There's no dodging that. It's science, not a mystery.


----------



## Bbsound (Dec 16, 2011)

mcclary's electrical said:


> That's because you're trying to pin something on him that's not his fault.


I would not even consider running #12 310 feet to feed a recpt.


----------



## brian john (Mar 11, 2007)

Show the ignorant fool this.

http://www.csgnetwork.com/voltagedropcalc.html


----------



## flyingspade (Apr 9, 2009)

Here's a simple online voltage drop calculator: 
http://www.southwire.com/support/voltage-drop-calculator.htm
(You can even use a load of 10 amps here and show #6 is needed)

Here's the NEC article to reference:
NEC (2011): *210.19 (A) (1) Informational Note #4*

Have both documents in hand and give to electrician, ask him to work with you to resolve this issue. Maybe there was a miscommunication, or maybe this electrician doesn't understand voltage drop. It is always good to have something in hand when discussing a problem. Remember, a picture is worth 1000 words. 

However, maybe there was a miscommunication from the start? What sort of job is this for? New or remodel? Was this job engineered? Maybe wrong information was given? There are too many ways to point the finger at anyone.


----------



## micromind (Aug 11, 2007)

I would be willing to bet a lot that the sla is in fact sfa.....service factor amps.

The actual starting current of this motor would be somewhere around 80 or 90 amps at 115 volts at the motor terminals.


----------



## McClary’s Electrical (Feb 21, 2009)

micromind said:


> I would be willing to bet a lot that the sla is in fact sfa.....service factor amps.
> 
> The actual starting current of this motor would be somewhere around 80 or 90 amps at 115 volts at the motor terminals.


 

Very good point, they don't list a starting load amps on most motors.


----------



## Techy (Mar 4, 2011)

Local code here is actually 2% drop on services, 3% drop on branch circuits.


----------



## noarcflash (Sep 14, 2011)

Anything over 100', you need to upsize. It's just common policy. We have 1 air compressor in the shop where the wire heats up, and we see a voltage drop. It's boarding 100' give or take.

luckily it's a 200volt motor, so it's still running.


----------



## ohmega (Apr 19, 2010)

Have the electrician pull some 4/0 to a 20/120v recep. and put it on a 20a breaker. See if that works. :thumbsup:


----------



## ampman (Apr 2, 2009)

Techy said:


> Local code here is actually 2% drop on services, 3% drop on branch circuits.


which code is that


----------

