Re: Pace makers, speakers, magnetic fields

[owner-emc-p...@majordomo.ieee.org]

Hi Chris,
 
this is one of these subjects |I spend a lot of time looking into. I survey
locations, expecially office location in older buildings. In a nutshell:
 
I see typical fields in the region of 0.5 to 1.5 mG, when there is a
significant field ( eg near an "On-Site transformer ) it rearely gets more
than 13 mG.
 
BUT, if there is a wiring fault, then I have recorded as high as 120 mG at the
operators location, reaching 620 mG close to where the wiring was running in a
conduit.
 
FYI, it seems.... like more than 15 mG causes monitors to visibly begin
shaking. At least CRT ones.
 
Cheers,
 
Derek N. Walton
Owner, L F Research EMI Design and Test Facility
Poplar Grove,
IL 61065