Peter - 1) Agreed. Keep in mind that IEEE 802.3 compliant signals are unearthed SELV and how SELV is derived in the power source was not specified.
2) There are potential problems, but this is not to say insurmountable. I doubt, however, that LAN cable meeting Reinforced insulation requirements is commercially available. Please note that communications cable in the US and Canada carry ringing signals, far in excess of SELV. Many Type CM (with or without suffixes) cables are also rated for NEC/CEC Class 3 circuits. 3) I don't know, but my discussions with people involved in the IEEE 802.x standards development seem to indicate a problem, since safety _is_ on their minds. Also, it is likely that undetermined (generic/nonproprietary) terminal equipment, or whatever is connected to the far end of the cable, will expect only IEEE/safety standard compliant currents/energies/powers/voltages in/on the cable. If they have an end-to-end product offering and all appropriate instructions and warnings to use only with their equipment and to not mix with other vendor's equipment, then perhaps there is an out. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina Homologation Services [email protected] > -----Original Message----- > From: Peter Merguerian > Sent: Thursday, April 19, 2001 1:02 AM > > Dear All, > > snip < > > An ITE manufacturer would like to use the extra > leads on a LAN cable to > power up his proprietary units in the LAN system > through a splitter which > can deliver up to 50 Vac (max 3.0 A) power > dervived from a power supply > unit. Other ITE manufacturers' equipment may be > connected to the same LAN by > means of the cabling (not 50 Vac powered) coming > out of the splitter. > > Question 1: I sense a problem in that the SELV > voltage limits are exceeded > and that a stnadard LAN cable may not have the > reinforced insulation between > the 50 Vac secondary hazardous voltage leads and > the SELV leads. Does > everyone agree? > > Question 2: Assuming manufacturer found a LAN > cabling which meets the > reinforced insulation requirements and he > specifies the use of this cabling > in the building, does anyone see a problem with > any country code > requirements (USNEC, Canada CEC, Europe, etc.)? > > Question 3: Does anyone see in problems with > meeting the LAN international > perfomance standards (IEEE, etc.)? > > > Thank you. > > > PETER S. MERGUERIAN ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
