Greetings, Please excuse my lack of experience but I am trying to understand the basic configuration for overvoltage and overcurrent tests.
ITU-T Recommendation K.11, K.21 discusses the difference between exposed and unexposed areas and the possible need for primary protection in exposed areas. We include, as a standard part of our installations, a primary protection card (with gas-arrestors and tranzorbs) to protect our equipment against overvoltages from the telecommunication lines. We connect in parallel to terminal equipment for monitoring purposes. If a protection card is an 'immutable part' of the equipment, why is it that Table 1/K21 states prescibed tests that both include and exclude primary protection? If we define primary protection to be part of our 'black box', why are there tests prescibed for both for with and without primary protection or am I interpreting it wrong in that only the tests with added protection is applies in our case? What is generally the accepted test configuration for administrations in most countries? Your interpretation and experience would be much appreciated. Thanks in advance. Chris --------------------------------------- Chris Visagie Hardware Design Engineer DataFusion Systems . Box 582 . Stellenbosch 7599 . South Africa Tel: +27 21 888 2000 Fax: +27 21 888 2200
