For what it's worth, I recall wind-up watches with cases which were labelled "non-magnetic". My assumption is that a magnetic field can affect the movement, although I wouldn't think an AC magnetic field would matter unless it was very strong.
A more likely reason for not wearing watches (or jewelry of any kind) is basic safety around live circuits. No jewelry, no neckties (or kerchiefs), and one hand in the pocket are still good rules. Jack Jacob Z. Schanker, P.E. Director of Agency Compliance Microwave Data Systems 175 Science Parkway Rochester, NY 14620 USA +716 242 8454 (voice) +716 241 5590 (fax) [email protected] ------------------------------------------ > ---------- > From: Mike Hopkins[SMTP:[email protected]] > Sent: Tuesday, March 30, 1999 4:10 PM > To: '[email protected]'; [email protected] > Cc: [email protected] > Subject: RE: EMC for automation & control - Electricity utilities > (UNIPEDE ) > > Very interesting -- my father also worked for what was then New England > Power and was a substation operator in Tewksbury, MA -- he also went to > other smaller sub-stations to switch lines in or out for maintence or to > clear trouble problems and I have similar recollections about the > electricity "in the air" -- you really could feel it! An interesting side > note - he could never wear a watch of any kind -- they would either run in > their own time zones or not work for long at all -- he attributed this to > the surrounding electric fields, but I've never figured out how that would > affect a mechanical watch!. > > As for ESD (human ESD) as opposed to AC electric or magnetic fields, the > levels of 8kV and 15kV (contact/air) are on the high side. Discharges of a > few kV happen all the time without us even knowing it; discharges that we > feel on a dry day are typically in the 5 to 10kV range, but a 15kV > discharge > from the end of your finger is something you'd remember! Even 10kV is > pretty > uncomfortable...... > > Hope this is helpful, but I doubt it would influence the people who wrote > the standard... > > Mike Hopkins > [email protected] > > > > -----Original Message----- > > From: [email protected] [SMTP:[email protected]] > > Sent: Tuesday, March 30, 1999 10:26 AM > > To: [email protected] > > Cc: [email protected] > > Subject: Re: EMC for automation & control - Electricity utilities > > (UNIPEDE) > > > > Peter, > > > > My father worked for the electric utility for many years. There were > times > > he could take me with him to check on how a substation was working after > > some maintenance or upgrade was performed. From direct experience I can > > tell you that when you enter the substation building, you can quite > often > > feel and smell the electricity in the air. The electrostatic fields that > > build up in these environments can be substantial. Yes, everything > inside > > is well grounded, but when you have thousands of volts running around > big > > copper bus bars, switching systems, transformers, etc. you hear the hum > > and feel the electricity in the air. Back then, I thought it was really > > neat as I did not have the healthy respect that I have since acquired > the > > hard way. > > > > One other thought here, would you want your TV going blink just at the > end > > of the local cricket match or the last quarter of the World Cup > "football" > > game? That could happen if some protective device or overcurrent sensor > > got zapped and caused a shutdown when there was really no system problem > > requiring a shutdown. > > > > > > Scott > > [email protected] > > > > > > [email protected] writes: > > >Hi. > > > > > >I've recently been shown a standard published by a European group > called > > >UNIPEDE titled "Automation and Control Apparatus for Generating > Stations > > >and Substations - Electromagnetic Compatibility Immunity Requirements" > - > > >Ref# 23005Ren9523. > > > > > >This standard generally adheres to the same requirements for immunity > as > > >the CE-mark standards, however for ESD it requires 8kV contact and 15kV > > >air > > >for HV substation environments. As is usually the case, there's no > > >rationale provided as to why these levels where chosen (something that > > >really annoys me about most standards). > > > > > >Does anyone have suggestions as to why the authors of the standard > would > > >expect worse ESD conditions in a substation than they seem to expect in > > an > > >air conditioned, carpeted office? (equipment in environments other than > > HV > > >substations only need meet 6kV contact, 8kV air according to this > > >standard) > > > > > > > > > > > > >------------------------------------------------------------------------- > > >Please note: The views, opinions and information expressed and/or > > >contained herein do not necessarily reflect the opinions or views of > > >Foxboro, the organisation/s through which this communication was > > >transmitted > > >nor any other third party, unless explicitly stated so. > > > > > >Peter Poulos (Hardware Design Engineer) > > >Foxboro Australia > > >42 McKechnie Drive, Eight Mile Plains, QLD, Australia 4113 > > >Tel:+61 (07) 3340 2118 Fax: +61 (07) 3340 2100 > > >E-mail:[email protected] > > > > > > > > --------- > > This message is coming from the emc-pstc discussion list. > > To cancel your subscription, send mail to [email protected] > > with the single line: "unsubscribe emc-pstc" (without the > > quotes). For help, send mail to [email protected], > > [email protected], [email protected], or > > [email protected] (the list administrators). > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
