Statistics on impedance values

[underequator]

I am a brazilian engineer and we are going to produce some electrical equipment to US market. To better design it, we need to have a better idea about the values of impedance we can expect from distribution panel to outlet. I know there is just a maximum value that can be found on IEEE stardards (0.8 to 1.0 Ohms), but does someone knows if there is a statistics about this? What is the average value?
Thanks for all!!

 

[ron]

Re: Statistics on impedance values

I'm not sure which impedance you are referring to? In addition, which IEEE standard references 0.8 to 1.0 ohm, so that we can better understand the application?
Impedances of conductors can be found in the National Electric Code and many cable manufacturers literature.

 

[underequator]

Re: Statistics on impedance values

Hi Ron. Thanks for your answer.
In fact, the equipment is a monophase induction motor, and I need to know the voltage range I could have on the motor terminals on starting condition.
As far as I know, the service voltage range (measured at the point of delivery) can vary from 106 to 127V (considering "Range B" zones). From that point to the motor terminals I have no idea what will be the voltage drop. It is dependant of two different impedances:
1) electrical installation impedance;
2) motor cable impedance.
I can measure some cables we have here, but I still don't have the impedance of the installation (from the point of delivery to the outlet). I know it varies a lot, but if there is any way to gather some statistics, it will be extremelly useful.
Thanks.

 

[physis]

Re: Statistics on impedance values

Usually we try to keep the voltage at the outlet within 5% of the voltage delivered by the utility.

The utility tries to stay within 5% too so that in general there is a 10% voltage tolerance.