I can tell you that the safety distance on 400kV is 4 Meters.... Still a little close for me... Steve -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of YES NOPE9 Sent: 03 June 2010 20:56 To: Microcontroller discussion list - Public. Subject: [EE] Low ( safety ) voltages across the world stuff you can touch !!!<=== little lightning bolts After doing some research , I discovered that my recollection of 48 volts being the threshold between "safe" voltages and "dangerous" ones could not be substantiated. = OZ seems to think 50 V a.c. or 120 V ripple-free d.c. is the ticket AS/AZS 3000:2007 definitions 1.4.98 = The IEC appears to agree. = The NEC seems to waffle. In 110.26(A)(1)(b), voltages of not greater than 30 volts ac rms and 60 volts dc are the dividing line. Article 720 is titled "Circuits and Equipment Operating at less than 50 volts." Article 725 uses tables which list voltages from 0 through 150 volts ac and dc. = In California, you are required to get a C-7 license for low voltage contracting. It is regulated by the Contractor's State License Board and overseen by the Department of Consumer Affairs. C-7 License: Low Voltage Systems Contractor Installs, services and maintains all types of communication and low voltage systems which are energy limited and do not exceed 91 volts. These systems include, telephone systems, sound systems, cable television systems, closed-circuit video systems, satellite dish antennas, instrumentation and temperature controls, and low voltage landscape lighting. Low voltage fire alarm systems are specifically not included in this section. = Florida Statue 489.503(14a) says that if the job has a fair market value of less then $1000, you do not need a low-voltage license. This applies to alarm cabling and the like under 77 volts. Maybe someone who knows for sure could comment. Gus -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist