From: Heiko Kuehling/Jpn/TUV <[email protected]> List-Post: [email protected] Date: 14 Mar 97 10:27:23 Subject: Hand held Probe Assemblies and Oscilloscopes acc to EN 61010-1 and EN 6101-2-031
Clearance and Creepage Distances for Hand held Probe Assemblies acc to EN= =20 6101-2-031 1) We have a passive probe type C (max. AC/DC 600V, Pollution Degree ) fo= r=20 connection to a oscilloscope. The=20 connection will be via a BNC connector (locking type).=20 Clause 6.4.102 describes the protection for connectors in Normal conditio= n. We=20 consider the BNC connector as=20 (when fully mated) a connector, which is not intended to be hand held aft= er=20 connection. According to 6.4.102a)=20 Basic Insulation to live parts would be accpetable. Clearance and Creepage and creepage distances within the compensating box= do=20 not compply with the requiremnts=20 (3mm considered due to material group 1) In addition the high voltage tes= t with=20 AC 2200V failed. Our test=01%s have shown=20 that the probe would pass with a test voltage of about AC 700V. Question: The probe will be connected to an earthed oscilloscope anyway.=20 Appropriate warning are given in the user=20 manual, that only earthed oscilloscopes shall be used to avoid electric s= hock=20 hazards.=20 The BNC - connector is in this way connected to an earthed system. Can th= is=20 locked connecter be considered as a=20 reliable PE - connection??? This would mean, that within the compensating box no clearance and creepa= ge=20 distances from line to accessible metal=20 parts of the BNC connector are required. 2) In regard to question 1, how are requirements for the input of an=20 oscilloscope. Is basic insulation from line to PE (metal=20 enclosure) with material group 1 acceptable ? I think, Part one alone of = EN=20 61010 doesnt give us the appropriate answer for this case.=20 3) According to EN 61010-2-032 clause 6.4.104 cables shall comply with th= e=20 requirements for reinforced or double=20 insulation. Type A and C probe assemblies require minimum 125V or rated voltage.=20 Does anybody has a simple idea, why 125V. Some people assumed, it might b= e,=20 because in the US is a 120V- system=20 But how knows the connection in this point ? Heiko K=81hling T=9AV Rheinland=20 Yokohama Laboratory e-mail [email protected]
