electromagnetic forces on busbar in lv switchgear

i READ THAT AND IT SEENS TO ME THAT THERE SHOULD BE MORE TO CONSIDER THAN JUST WHAT WAS WRITEN! pROPORTIONAL? Perhaps yes, but absolutily NO! no matter what "Formula" one uses for figuring materials as such one should remember one thing and one thing only! Molecular structure of any substance on earth caries a certain amount of "power" of one form and we humans call this electricity!

So answer that: NO! each bar was made different from the other! There will be a difference in electromagnetic force for each material made! then wheather they are closer or not does not matter!

Dwight's chart provides an "adjustment" for forces between conductors that are not "filamentary". Because current spreads across a larger area, the forces between a pair of conductive straps/bus bars tend to be less than that for a pair of filamentary conductors separated by the same distance. What Dwight's chart basically says is that, as you separate the busbars, they behave more similarly to a pair of filamentary conductors so that the correction factor ("k") approaches unity. Herbert Bristol Dwight originally presented a similar set of curves in his book "Electrical Coils and Conductors", McGraw-Hill, 1945 (a fairly scarce title now).

Sir, you seem to be very well informed on this matter. The original question seems a bit vague. This drew my attention, as I work for a TelCo that has power equipment dating back to cir. 1970. We rectify 3-phase delta 240AC to (-)54VDC. We average about 1200-1400 amps that float 3 parallel strings of flooded PbCa cells. We push all of this current to the Main Fuse Panel via 2 buss bars..each buss consists of 4 bars of 4" x 1/4" Cu. approx 30' inside the power room. From there it is sent to the switching equipment via multiple runs of 750 MCM cables of about 150' in 1 over head cable rack.

I have been wondering just how 'large' and robust of an electromagnet field is produced, and whether or not itcould produce malicious EMF in nearby cables or digital equipment... you seem to be the first person that I have confidence in your opinion..thanks

If our enquirer has to ask if any force is directly proportional to the distance between the bodies involved,then I dont think he should do any engineering let alone busbars.

I hope he doesnt get any further from me or the repulsive force will become unbearable.

please note that the problem exists in that the constant seems to indicate that the forces are inversely, not directly proportional. - you might try to read before you write.

For exhaustive treatment of busbars,including the function to calculate 'k' the proximity factor,which has more terms in it than rocket science,(Dwight, 1917) go to:-

www.cda.org.uk/megab2/elecapps/pub22/sec1

If you want only info on electromagnetic stresses in place of 'sec1', put 'sec6'

This is a mind boggling treatise on busbars,by the Copper Development Association.I've never found out how many pages it has,I just dip into the bit I need,it even gives design data for hex insulated systems up to 32kV and 400kVA.Stand well back before switching on.