Xing, Look up Annex D of the IEC 60950 standard. This annex gives you two alternative methods for the measuring instrument (figures D.1 and D.2). Regards
This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il <http://www.itl.co.il/> http://www.i-spec.com <http://www.i-spec.com/> -----Original Message----- From: xingwb [mailto:[email protected]] Sent: Tuesday, June 25, 2002 11:57 AM To: Peter Merguerian Cc: [email protected] Subject: Re: TOUCH CURRENT LIMIT Hi Mr. Peter: Our test lab receive a CB TEST REPORT FOR NATIONAL RECOGNIZATION, the EUT is a class II ac adapter having a bridging capacitor (4700pF)across the reinforced insulation The touch current measured by CB is 0.17mA(4700pF declared) but the value we measure is 0.28mA(4700pF) which one is correct ? it depend on test equipment? How to judge How to obtain accurate result? any comments are appreciated Xing weibing 2002-06-25 17:56 ----- Original Message ----- From: Peter <mailto:[email protected]> Merguerian To: 'xingwb' <mailto:[email protected]> ; Robert <mailto:[email protected]> Johnson ; Peter Merguerian <mailto:[email protected]> Cc: [email protected] <mailto:[email protected]> Sent: Tuesday, June 25, 2002 6:38 PM Subject: RE: TOUCH CURRENT LIMIT Xing, Yes, 0.25mA is very strict for 950. However, I can assure you that depeding on the test lab and uncertainty of the test equipment, you will obtain slightly different results. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il <http://www.itl.co.il/> http://www.i-spec.com <http://www.i-spec.com/> -----Original Message----- From: xingwb [mailto:[email protected]] Sent: Tuesday, June 25, 2002 11:13 AM To: Robert Johnson; Peter Merguerian Cc: [email protected] Subject: Re: TOUCH CURRENT LIMIT Dear SIRS: Thanks for your e-mail A further question for touch current: Is it (0.25mA) strict for Class II equipment ? 0.28mA rms is OK FOR IEC60065 0.28mA rms is not OK for IEC60950 Any comments are appreciated Best Regards XING WEIBING 2002-06-25 ----- Original Message ----- From: Peter <mailto:[email protected]> Merguerian To: 'xingwb' <mailto:[email protected]> ; [email protected] <mailto:[email protected]> Cc: Ilan Cohen <mailto:[email protected]> ; Michael G <mailto:[email protected]> ; Shmuel <mailto:[email protected]> Gnatt ; Sima <mailto:[email protected]> Beloborodov ; Valery Rodionov <mailto:[email protected]> Sent: Monday, June 24, 2002 9:00 PM Subject: RE: TOUCH CURRENT LIMIT Xing Hello! ake a look at IEC 60990, "Methods of measurement of touch current and protective conductor current". The limits in IEC 60 950 are based on this particular standard. Best Regards This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il <http://www.itl.co.il> http://www.i-spec.com <http://www.i-spec.com/> -----Original Message----- From: xingwb [mailto:[email protected]] Sent: Monday, June 24, 2002 1:57 AM To: [email protected] Cc: Rich Nute Subject: TOUCH CURRENT LIMIT Dear colleagues I have a question regarding touch current limit of IEC 60950? We can read from table 5A of IEC60950:1999: Touch current limit for accessible parts and circuits not connected to protective earth: 0.25 mA question 1 : How does it (0.25mA) come from and what it is based on? based on IEC479? OR other source why it is not 0.5mA(based on IEC60479) question 2 :for hand-held equipment it is 0.75mA why ? Please shed some light for above questions Any comments are appreciated Best Regards Xing weibing 2002-06-24
