John, Look at Clause 3.8 of ANSI/ISA S82.01-1994 (US harmonized version of IEC 1010-1) for a definition of "mains". Clause D.1 means that if your circuit (input or measuring) DOES NOT connect to the mains, then you may test according to the single fault conditions of Clause 4.4. For example; if your instrument takes a measurement of the voltage at a wall socket of 120 V then you must meet the CREEPAGE AND CLEARANCE requirements .
Dan Teninty P.E. Senior Product Safety Engineer [email protected] FLUKE Corporation Everett, Washington (206) 356-6035 (206) 356-6490 fax I=92ve never been able to fully determine the intent and meaning of clause D.1 of IEC1010-1, which states: <Circuits, other than mains circuits, that fail to comply for CLEARANCE and CREEPAGE DISTANCE may be accepted, if compliance is achieved under the fault conditions described in 4.4 and if HAZARDOUS LIVE parts are not accessible after a fault.> Suppose I have a double insulation system which relies on both supplementary insulation and basic values of creepage and clearance (C&C) to keep the operator safe from hazardous live (non-mains) conductors. Couldn=92t I invoke D.1 to permit me to make my C&Cs as small as I want, thereby effectively reducing my entire insulation system to that of basic levels? =20 Am I completely missing the meaning of D.1, and if so, can anybody explain the intent and ramifications of this clause? =20 Regards, John Quinlan [email protected] =20
