Regarding the sewing machine with two distinct ratings - this is somewhat common, and I have done it for some of my employer's products. The label should clearly indicate the regional basis of the ratings. That is, there should be an agency's NRTL/SCC logo associated with the 120V, and a CE or other international mark with the 240V rating. Done due to country-specific cord set shipped with unit and ratings of certain components due to national differences.
Basis for rating info on label of consumer product based on regional electric code and marking requirement in scoped safety standard. Basis for rating on a component is to verify comformity. Note the rationale in 60950-1: "Equipment shall be provided with a power rating marking, the purpose of which is to specify a supply of correct voltage and frequency, and of adequate current-carrying capacity." Agree that markings are not always clear to the consumer, perhaps not intended for the customer - "Ask not for whom the bell tolls. It tolls for thee." [poor metaphor] Brian -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Richard Nute Sent: Friday, January 27, 2012 12:46 PM To: 'McInturff, Gary'; [email protected]; [email protected] Subject: RE: [PSES] Is this common knowledge - Electrical Ratings My nifty Samsung TV is rated 100-240, 50/60 Hz. Per the discussion here: 100-240 indicates a continuous range; 50/60 Hz implies two discrete switchable ranges. As mentioned in this discussion, 50/60 implies a range of frequencies between 50 and 60 where the TV would not operate. Of course, as everyone recognizes, there is no switch for frequency. And, the TV would operate at any frequency between 50 and 60. Even among ourselves (product safety professionals), we do not apply the rating markings consistently. There is no justification for expecting the user to distinguish between a - and a /. The user buys an appliance locally, and it comes with a cord an plug for local use. The markings are not read prior to installation. Neither do the installation instructions instruct the user to check the ratings before installation. The manufacturer does this for the user by shipping a fully configured product to the retailer. Table lamps don't have rating markings. What, then, is the value of the ratings markings? For that matter, what is the safety function of the ratings markings? Finally, for whom are the rating markings intended? Best regards, Rich ps: My wife's Pfaff sewing machine has two ratings: 120 V, 50/60 Hz certified by UL and CSA. 220-240 V, 50/60 Hz certified with CE and others. The ratings are distinctly separate, but on the same label. No switch. Its quite clear the unit operates 120-240 and 50-60. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
