Ron - Different UL standards have different requirements for these capacitors. It is my understanding that:
UL1950 (ITE) does not have an issue specifically with UL1283 capacitors (yet) UL1459 (Telephone Equipment) does have requirements specifically requiring UL1414 capacitors (which if memory serves, is where you encountered this issue), if used as discrete components and not integral to an EMI filter product. My last contact on this topic was that UL1283 EMI appliance filter products were allowed for use in products evaluated to UL1459 (this should not have changed and hasn't to my knowledge); also UL1283 evaluations had begun (by at least 1993) the process of including "suitable for use in telephone equipment" for component type filters, with specific statements included in the Conditions of Acceptability, implying UL1414 capacitors were used in the filter. Other standards for household appliances, such as audio and video equipment also have these requirements (in fact, UL1414 came about specifically because of these product categories). There may be others. Based on my last reading of UL1283 (probably 1994 and my understanding could be dated), you are correct that the requirements in UL1414 are much more severe than for UL1283, both in regards to construction and type testing performance criteria. The only line I can point to to delineate when UL1283 is OK or when UL1414 capacitors are required is to look at each end-product safety standard. A poorly digestible suggestion, but all there is. In any case, it is easily discernible that a capacitor evaluated to UL1414 will provide a greater level of safety than one evaluated to UL1283 (unless UL1283 has upgraded their requirements to match UL1414). It's this "greater level of safety contemplated by the standard" that was used to justify the requirement in UL1459. Regards, Peter L. Tarver Nortel ptar...@nt.com >---------- >From: ron_pick...@hypercom.com[SMTP:ron_pick...@hypercom.com] >Sent: Thursday, February 19, 1998 7:46 AM > > Rich, > > You state in your reply that: > > >If the capacitors bear a certification mark (e.g., SEMKO or UL), then > >the capacitors have been appropriately tested and comply with the > >IEC384-14 requirements for double/reinforced insulation, or with > >UL 1414 equivalently. As such, no further testing of the capacitors > >is necessary. > > > >If the capacitors do not bear a certification mark, then it is > >appropriate to test the capacitors per the applicable standard, > >IEC 384-14 or UL 1414. (I doubt ordinary capacitors will pass these > >tests!) > > UL has another category for Recognizing capacitors for the purpose of >EMI > filtering across the line (X) and from phase-to-ground (Y), which is > UL1283, "Electromagnetic Interference Filters (FOKY2)". There are >several > manufacturers with capacitors listed and some products are listed in >both > categories. Although I'm not intimate with either standard, I believe >that > UL1414 has the more stringent requirements of the two. > > This thread has also resurrected a past experience in my mind. In a past > life, I remember that selecting a UL1283 capacitor was not allowed by UL > because it was connected across-the-line. We had to select a UL1414 > capacitor instead even though the capacitor selected was intended for >the > purpose of EMI filtering. > > So, to those more knowledgeable, as assembled UL1283 EMI filters with >maybe > IEC320 connector, switch, fuseholder, etc included are allowed to >connect > across the line, why aren't the UL1283 EMI capacitors (X) allowed to > connect for the same purpose? Or is it the fact that they are contained > within the greater filter's enclosure? > > When is use of UL1283 capacitors allowed and not allowed? What's the > delineation of acceptability of UL1283 vs UL1414? > > I look forward to any meaningful comments. > > Best regards, > Ron Pickard > rpick...@hypercom.com > > >
