voltage drop

resistance of both current carrying cores multiplied by operating current.
 
Here in the USA we use this formula 2LAR/1000. L=length A=amps R=resistance we have a table in our code book that gives the resistance per 1000'. Do you have something similar?
 
In BS7671 (also referred to as the iee regulations) for the UK we have tables for volt drop for a given type of cable and csa of conductor. This is given in mV/A/m, millivolts per amp per meter.

(mV/A/m figure)*Ib*L / 1000 = volt drop where Ib is design current of circuit and L is length in meters.
 
Frank35 said:
Here in the USA we use this formula 2LAR/1000. L=length A=amps R=resistance we have a table in our code book that gives the resistance per 1000'. Do you have something similar?
Click to expand...

pretty much, we generally give the resistance of both phase cores in the table rather than doubling it afterwards but yeah otherwise pretty much the same.
 
We use the same in the UK.

We have tables in the back of our Regs Books (BS7671:2004) that gives the maximum load of a particular size and type of cable, giving several different ratings for installation method. Then below this table will be another which gives the volt drop for the given cable.

The calculation is mV*I*L/1000

or Volt drop per amp per meter * Current * Length and divided by 1000 to give the correct voltage. In the uk we are limited to 4% of the supply voltage or 9.2V@230V
 
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