CHANGING # OF CURRENT CONDUCTORS AND WIRE SIZE

Status
Not open for further replies.
C

Clojo

New member
Location
Garden city New york Usa
I am not an electrician- however I have a situation I am trying to understand.

my electrical contractor send me a table where
he has a 417 ft run 600amp circuit breaker fed by 4-500 AL .
THE ARCHITECT CALCULATION OF THE RUN WAS 250FT
The contractor is proposing a 2-500 AL instead
I have a meeting this morning to discuss this scenario but I am trying to enter the meeting with some kind of reference point.( ITS A WHOLE TABLE I JUST CHHOSE ONE)
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
You need to learn what constraints drive the size of wire so that you can understand what is going on.

The wire needs to be large enough to carry the maximum expected current. This is the minimum size the wire can be.

The wire also causes 'voltage drop' and depending upon the length of the run may need to be larger than the minimum to reduce this to an acceptable value. 'Acceptable value' depends on what the connected load can tolerate and the supply voltage.

There are additional factors which adjust things. For example wires routed together heat each other up and reducing the allowed current rating. Temperature also adjusts the current rating and changes the voltage drop value.

-Jon
 
Status
Not open for further replies.
Top