Subject: What are ground loops?

    Often when I set up equipment to make highly sensitive electrical 
measurements for my research, noise is a constant problem.  Over the years 
I have learned how to deal with noise problems by following a certain set 
of rules, such as avoiding ground loops.  However, no one has ever 
explained to me the precise physical basis for ground loops.
    Now clearly ground loops are not a problem when everything is grounded 
with very thick wire.  However, extremely think wire is often not 
practical.  Under these circumstances, why exactly does the topology of the 
ground bus matter?  Also, it would be extremely helpful to me to hear a 
physicist's version of the best way to ground sensitive electronic 
equipment.

Thanks for your time.

Re: What are ground loops?