Definition of Residual Current
I am working on a standard for which a definition of Residual Current is needed. I don't own any other standard that defines it, and I don't subscribe to the IEC electrotechnical vocabulary (perhaps I should). At any rate, I could use some help please. 1. Does anyone have an official definition for me? Please state your source. 2. According to the standard for RCCB's, IEC 61008-1, here's the definition (translated from German to English by a colleague, so perhaps not verbatim from the English version of the standard): Residual current: "Vector sum of the actual values of the currents flowing in the main circuit of an RCCB" That seems like a pretty poor definition to me, as it is circular and a bit vague (I'm guessing "main circuit" should read "mains circuit" but still that could be interpreted to include the earth wire in which case it's incorrect). I think the definition does not need to and should not make any reference to an RCCB, because residual current exists whether or not an RCCB is used, and using RCCB in the definition just requires a definition of RCCB, leading back to a need to define what Residual Current is. I think the definition should be something like this: "Residual Current: The vector sum of the currents in each phase and neutral (if applicable), which if non-zero indicates that current is returning to the source via a path other than the current-carrying conductors, which therefore indicates a potential shock hazard." Comments? Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Definition of Residual Current
In message , dated Fri, 3 Feb 2006, Jim Eichner writes >John: Are "such words of explanation" allowed in an IEC standard, or do >the standards have the same limitation applied to them as the IEV has? The same limitation. The IEV is largely derived from definitions in standards. Explanation can be put in a Note below the definition, but long Notes are discouraged. Often, it's better to put explanation elsewhere in the standard, maybe in an Informative Annex if it's extensive. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Definition of Residual Current
In message , dated Fri, 3 Feb 2006, Ralph McDiarmid writes >Perhaps "resultant current" or "net RMS current" would have been better >than "vector sum". A vector sum implies to me, drawing the vectors and >adding them graphically, or adding their real & imag rectangular >components. Vector summation takes phase into account, or, what is the same thing, real and imaginary components. > >If I recall correctly, the RMS (effective) value is also the >square-root of the algebraic sum of the squares of the magnitudes of >the harmonic terms. Yes, and eliminates phase information. That's why we have to put it back in to calculate: power = VIcos[phi] > >I understand that these RCCB devices do this sum, presumably by a >resultant flux in a magnetic circuit. Now, how would a magnetic circuit calculate RMS values? (I wish it could.) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Definition of Residual Current
John: Are "such words of explanation" allowed in an IEC standard, or do the standards have the same limitation applied to them as the IEV has? Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Friday, February 03, 2006 11:35 AM To: emc-p...@ieee.org Subject: Re: Definition of Residual Current In message , dated Fri, 3 Feb 2006, Jim Eichner writes >I am working on a standard for which a definition of Residual Current >is needed. I don't own any other standard that defines it, and I don't >subscribe to the IEC electrotechnical vocabulary (perhaps I should). At >any rate, I could use some help please. > >1. Does anyone have an official definition for me? Please state your >source. There are several in the IEV, but see below. Some apply only to 3-phase supplies without a neutral conductor. > >2. According to the standard for RCCB's, IEC 61008-1, here's the >definition (translated from German to English by a colleague, so >perhaps not verbatim from the English version of the standard): > >Residual current: "Vector sum of the actual values of the currents >flowing in the main circuit of an RCCB" > >That seems like a pretty poor definition to me, as it is circular and a >bit vague It's close to the IEV definition 442-05-19: r.m.s. value of the vector sum of the currents flowing through the main circuit of the residual current device But yes, your 'translator' had better not give up the day job. (;-) >(I'm guessing "main circuit" should read "mains circuit" but still that >could be interpreted to include the earth wire in which case it's >incorrect). No, 'main circuit' excludes the earth wire. > >I think the definition does not need to and should not make any >reference to an RCCB, because residual current exists whether or not an >RCCB is used, and using RCCB in the definition just requires a >definition of RCCB, leading back to a need to define what Residual >Current is. > >I think the definition should be something like this: > >"Residual Current: The vector sum of the currents in each phase and >neutral (if applicable), OK so far, and similar to another, but less satisfactory, IEV definition, which says 'algebraic' instead of 'vector' and is thus not really correct. >which if non-zero indicates that current is returning to the source via >a path other than the current-carrying conductors, which therefore >indicates a potential shock hazard." Such words of explanation are not permitted in an IEV definition. > -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Definition of Residual Current
Perhaps "resultant current" or "net RMS current" would have been better than "vector sum". A vector sum implies to me, drawing the vectors and adding them graphically, or adding their real & imag rectangular components. If I recall correctly, the RMS (effective) value is also the square-root of the algebraic sum of the squares of the magnitudes of the harmonic terms. I understand that these RCCB devices do this sum, presumably by a resultant flux in a magnetic circuit. == Ralph McDiarmid, ASc Compliance Engineering Group Xantrex Technology Inc. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Friday, February 03, 2006 11:35 AM To: emc-p...@ieee.org Subject: Re: Definition of Residual Current In message , dated Fri, 3 Feb 2006, Jim Eichner writes >I am working on a standard for which a definition of Residual Current >is needed. I don't own any other standard that defines it, and I don't >subscribe to the IEC electrotechnical vocabulary (perhaps I should). At >any rate, I could use some help please. > >1. Does anyone have an official definition for me? Please state your >source. There are several in the IEV, but see below. Some apply only to 3-phase supplies without a neutral conductor. > >2. According to the standard for RCCB's, IEC 61008-1, here's the >definition (translated from German to English by a colleague, so >perhaps not verbatim from the English version of the standard): > >Residual current: "Vector sum of the actual values of the currents >flowing in the main circuit of an RCCB" > >That seems like a pretty poor definition to me, as it is circular and a >bit vague It's close to the IEV definition 442-05-19: r.m.s. value of the vector sum of the currents flowing through the main circuit of the residual current device But yes, your 'translator' had better not give up the day job. (;-) >(I'm guessing "main circuit" should read "mains circuit" but still that >could be interpreted to include the earth wire in which case it's >incorrect). No, 'main circuit' excludes the earth wire. > >I think the definition does not need to and should not make any >reference to an RCCB, because residual current exists whether or not an >RCCB is used, and using RCCB in the definition just requires a >definition of RCCB, leading back to a need to define what Residual >Current is. > >I think the definition should be something like this: > >"Residual Current: The vector sum of the currents in each phase and >neutral (if applicable), OK so far, and similar to another, but less satisfactory, IEV definition, which says 'algebraic' instead of 'vector' and is thus not really correct. >which if non-zero indicates that current is returning to the source via >a path other than the current-carrying conductors, which therefore >indicates a potential shock hazard." Such words of explanation are not permitted in an IEV definition. > -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Definition of Residual Current
In message , dated Fri, 3 Feb 2006, Jim Eichner writes >I am working on a standard for which a definition of Residual Current is >needed. I don't own any other standard that defines it, and I don't >subscribe to the IEC electrotechnical vocabulary (perhaps I should). At >any rate, I could use some help please. > >1. Does anyone have an official definition for me? Please state your >source. There are several in the IEV, but see below. Some apply only to 3-phase supplies without a neutral conductor. > >2. According to the standard for RCCB's, IEC 61008-1, here's the >definition (translated from German to English by a colleague, so perhaps >not verbatim from the English version of the standard): > >Residual current: "Vector sum of the actual values of the currents >flowing in the main circuit of an RCCB" > >That seems like a pretty poor definition to me, as it is circular and a >bit vague It's close to the IEV definition 442-05-19: r.m.s. value of the vector sum of the currents flowing through the main circuit of the residual current device But yes, your 'translator' had better not give up the day job. (;-) >(I'm guessing "main circuit" should read "mains circuit" but >still that could be interpreted to include the earth wire in which case >it's incorrect). No, 'main circuit' excludes the earth wire. > >I think the definition does not need to and should not make any >reference to an RCCB, because residual current exists whether or not an >RCCB is used, and using RCCB in the definition just requires a >definition of RCCB, leading back to a need to define what Residual >Current is. > >I think the definition should be something like this: > >"Residual Current: The vector sum of the currents in each phase and >neutral (if applicable), OK so far, and similar to another, but less satisfactory, IEV definition, which says 'algebraic' instead of 'vector' and is thus not really correct. >which if non-zero indicates that current is >returning to the source via a path other than the current-carrying >conductors, which therefore indicates a potential shock hazard." Such words of explanation are not permitted in an IEV definition. > -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
