Re: Surge Testing per EN 55024/EN61000-4-5
In the Test-Setup Section, Conditions during Testing of EN 55024 it is said: Test should be made in the most representative mode. To my understanding, in the present days most ITE Equipment and Peripherals comes with a 3-prong plug, i.e. it is grounded. So, if the EUT has external ports intended to be connected to ITE Peripherals , Surge Testing should be done Line to Ground, with the secondary side of the Equipment Grounded, or with a Grounded ITE Peripheral connected. Dipl.-Ing. Rene Charton Manager EMC Services _ TUV Rheinland Taiwan Ltd. TAIPEI HEAD OFFICE Spring Plaza Building 14F, No.6, Min Chuan E. Rd., Sec. 3, Taipei 104, Taiwan, R. O. C. Tel. (02) 2516 6040 Ext. [ 086 ] e-mail: r...@twn.tuv.com Please respond to Jim Hulbert hulbe...@pb.com To: emc-p...@ieee.org cc:(bcc: Rene Charton/TUV-Twn) Subject: Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list adminstrators: Jim Bacher: jim_bac...@mail.monarch.com, or Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Surge Testing per EN 55024/EN61000-4-5
Jim, You do in fact have a potential ground connection - at the phone line. In the static (on-hook) state you will have -48 Vdc, referenced to earth. If you look at your home phone service you will see a wire running to a cold water pipe, with a tag that says something like Telephone Company Ground - Do Not Remove. PBX systems at work will be different. I have little knowledge of whether they ground or not. I have learned the hard way to look for these non-obvious ground connections. Best wishes, Scott Lacey -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Thursday, March 02, 2000 8:52 AM To: Lacey,Scott; emc-p...@ieee.org Subject:RE: Surge Testing per EN 55024/EN61000-4-5 Scott, The product I'm currently looking at uses a 2 -prong AC mains plug. Actually the supply is small direct plug-in type with DC leads that connect to the product. The product itself is encased in plastic and the only other connection is through an internal modem board to a standard analog telephone line. The connection to the phone line is a simple 2-wire (tip and ring) configuration. As I see it, surge tests with reference to earth ground are pointless. Others have pointed out that an ungrounded product may in the real world actually have a reference to ground depending on how it is installed or what other equipment it is connected to. That is a good point which I hadn't thought about. However, I don't think that in my particular situation that's that case. Thanks to all who responded with their opinions. Jim Lacey,Scott sla...@foxboro.com on 03/01/2000 01:31:46 PM Please respond to Lacey,Scott sla...@foxboro.com To: 'Jim Hulbert' hulbe...@micro2.pb.com cc: 'emc-p...@ieee.org' emc-p...@ieee.org (bcc: Jim Hulbert/MSD/US/PBI) Subject: RE: Surge Testing per EN 55024/EN61000-4-5 Jim, I'm not quite sure from the description what your product looks like, but, here are a few things to keep in mind. If you use a 3-prong ac mains plug you absolutely should do the line-to-ground test. If you use a 2-prong ac mains plug you still might want to perform the test anyway, depending on how your product is used. For example, if your plastic housing may be DIN rail mounted or screwed to a wall, you may have a leakage or arc path to earth. Your customer may have deliberately grounded the DIN rail to satisfy the requirements of other vendor's equipment already mounted. Even if it only gets screwed to a plasterboard wall, it still may get grounded by accident. I have seen two such scenarios over the years. In the first instance one mounting screw went through the wallboard and touched the grounded sheath of a BX cable in an older building. In the second instance a screw penetrated a metal stud used to frame the wall. An outlet box was attached to another stud. Bingo - instant ground. I'm sure there are many who will disagree with me, but we test products not only to conform to a standard, but also to ensure a more robust product. I want to find any vulnerability first, before the product gets to a customer. Customers tend to get VERY angry when their new product hiccups, and the nasty stuff tends to flow downhill real fast when their CEO calls yours. Scott Lacey -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject: Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety
RE: Surge Testing per EN 55024/EN61000-4-5
Scott, The product I'm currently looking at uses a 2 -prong AC mains plug. Actually the supply is small direct plug-in type with DC leads that connect to the product. The product itself is encased in plastic and the only other connection is through an internal modem board to a standard analog telephone line. The connection to the phone line is a simple 2-wire (tip and ring) configuration. As I see it, surge tests with reference to earth ground are pointless. Others have pointed out that an ungrounded product may in the real world actually have a reference to ground depending on how it is installed or what other equipment it is connected to. That is a good point which I hadn't thought about. However, I don't think that in my particular situation that's that case. Thanks to all who responded with their opinions. Jim Lacey,Scott sla...@foxboro.com on 03/01/2000 01:31:46 PM Please respond to Lacey,Scott sla...@foxboro.com To: 'Jim Hulbert' hulbe...@micro2.pb.com cc: 'emc-p...@ieee.org' emc-p...@ieee.org (bcc: Jim Hulbert/MSD/US/PBI) Subject: RE: Surge Testing per EN 55024/EN61000-4-5 Jim, I'm not quite sure from the description what your product looks like, but, here are a few things to keep in mind. If you use a 3-prong ac mains plug you absolutely should do the line-to-ground test. If you use a 2-prong ac mains plug you still might want to perform the test anyway, depending on how your product is used. For example, if your plastic housing may be DIN rail mounted or screwed to a wall, you may have a leakage or arc path to earth. Your customer may have deliberately grounded the DIN rail to satisfy the requirements of other vendor's equipment already mounted. Even if it only gets screwed to a plasterboard wall, it still may get grounded by accident. I have seen two such scenarios over the years. In the first instance one mounting screw went through the wallboard and touched the grounded sheath of a BX cable in an older building. In the second instance a screw penetrated a metal stud used to frame the wall. An outlet box was attached to another stud. Bingo - instant ground. I'm sure there are many who will disagree with me, but we test products not only to conform to a standard, but also to ensure a more robust product. I want to find any vulnerability first, before the product gets to a customer. Customers tend to get VERY angry when their new product hiccups, and the nasty stuff tends to flow downhill real fast when their CEO calls yours. Scott Lacey -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject: Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list adminstrators: Jim Bacher: jim_bac...@mail.monarch.com, or Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac
RE: Surge Testing per EN 55024/EN61000-4-5
Chris, In the case you mention, setting the CD player in its normal position on a grounded steel plate should do. The unit may end up sitting on a steel shelf unit along with other equipment with grounded chassis. I used such a setup at home for years. Scott Lacey -Original Message- From: Colgan, Chris [SMTP:chris.col...@tagmclarenaudio.com] Sent: Thursday, March 02, 2000 4:41 AM To: emc-p...@ieee.org Subject:RE: Surge Testing per EN 55024/EN61000-4-5 Let's say I'm testing a Class II double insulated CD player - no reference to earth. If the product were stand alone, line to earth testing would be pointless, at least as I see it. It is conceivable that the CD player could be connected to a Class I, earthed amplifier. Through the interconnects, the chassis of the CD player could become grounded (there would probably horrendous hum problems but that's another story). Line to earth tests are now valid but how would I set this up in the lab? A lead from the CD player chassis to the nearest socket outlet earth? A lead to the chassis of my Keytek surge tester? A thin lead, a thick lead? I guess the test should be representative of the real world and repeatable. Any suggestions? Regards Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com -Original Message- From: Mike Hopkins [SMTP:mhopk...@keytek.com] Sent: 01 March 2000 18:32 To: 'Jim Hulbert'; emc-p...@ieee.org Subject: RE: Surge Testing per EN 55024/EN61000-4-5 As long as there is no other path to ground, a line to line test would be all thats required, but keep in mind, if you have other I/O, telecom, control lines, or anything else coming out of that plastic box, you then have a potential path back to ground, and in fact, will likely have REAL ground connections. For example, many television sets have two wire power plugs, are in plastic cases, but if you have cable tv, the odds are that coax cable is grounded. Same thing applies if there is a telecom line involved -- very likely one of the telecom lines is ground. .. Mike Hopkins mhopk...@keytek.com -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject:Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list adminstrators: Jim Bacher: jim_bac...@mail.monarch.com, or Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson
RE: Surge Testing per EN 55024/EN61000-4-5
Chris A comment, which is probably representative of many audio systems (although I do appreciate that your company makes fairly high end equipment!). My Yamaha AV tuner amp (RX-V592RDS) is Class II, as is most of the rest of the audio system, but the user manual states that it may be necessary to ground the chassis for noise reduction purposes and provides a terminal on the back for the purpose. I assume that this can be the star point for both the external and the internal earthing since it states nothing to the contrary. There werer certainly noticeable successive reductions in hum/noise on the phono input when, very recently, I earthed first the metal chassis of the (very old!) turntable to the star point, and then connected the star point to a the earth of a spare socket in the mains distribution block. Both of the above connections would be representative of what most people would do - I do'nt think many would star the earths at the mains-distribution block first as this could actually increase hum/noise problems due to increasing the size of the earth loops. Both earths were small diameter (0.5/0.75 sq mm or 20/18 AWG) and I would not expect anyone to use anything much larger unless specified in the installation instructions. The length of the turntable wire is about 2m and it is incorporated as a drain wire in the twin phono lead. The length of the wire from the star point is only some 0.5m as that is the actual distance required. I think these numbers will vary according to the needs to the actual user - OR according to what you state in the installation instructions! Maybe you need to consider real-life situations, make some tests and then specify the actual installation cabling requirements or options in the instructions. Then YOU will have more control of the situation and the pass/fail criteria. Regards John Allen Racal -- From: Colgan, Chris[SMTP:chris.col...@tagmclarenaudio.com] Sent: 02 March 2000 09:40 To: emc-p...@ieee.org Subject:RE: Surge Testing per EN 55024/EN61000-4-5 Let's say I'm testing a Class II double insulated CD player - no reference to earth. If the product were stand alone, line to earth testing would be pointless, at least as I see it. It is conceivable that the CD player could be connected to a Class I, earthed amplifier. Through the interconnects, the chassis of the CD player could become grounded (there would probably horrendous hum problems but that's another story). Line to earth tests are now valid but how would I set this up in the lab? A lead from the CD player chassis to the nearest socket outlet earth? A lead to the chassis of my Keytek surge tester? A thin lead, a thick lead? I guess the test should be representative of the real world and repeatable. Any suggestions? Regards Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com -Original Message- From: Mike Hopkins [SMTP:mhopk...@keytek.com] Sent: 01 March 2000 18:32 To: 'Jim Hulbert'; emc-p...@ieee.org Subject: RE: Surge Testing per EN 55024/EN61000-4-5 As long as there is no other path to ground, a line to line test would be all thats required, but keep in mind, if you have other I/O, telecom, control lines, or anything else coming out of that plastic box, you then have a potential path back to ground, and in fact, will likely have REAL ground connections. For example, many television sets have two wire power plugs, are in plastic cases, but if you have cable tv, the odds are that coax cable is grounded. Same thing applies if there is a telecom line involved -- very likely one of the telecom lines is ground. .. Mike Hopkins mhopk...@keytek.com -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject:Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org
RE: Surge Testing per EN 55024/EN61000-4-5
Jim, Does your product connect to any auxiliary equipment that has an earth connection, whether directly or indirectly? Don Umbdenstock Sensormatic -- From: Jim Hulbert[SMTP:hulbe...@pb.com] Reply To: Jim Hulbert Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject: Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list adminstrators: Jim Bacher: jim_bac...@mail.monarch.com, or Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Surge Testing per EN 55024/EN61000-4-5
Mike, can't agree with you on this one. See Scotts comments in his e-mail. You test to prove things are as you think they are... Otherwise why test at all? Derek Walton Invensys --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Surge Testing per EN 55024/EN61000-4-5
As long as there is no other path to ground, a line to line test would be all thats required, but keep in mind, if you have other I/O, telecom, control lines, or anything else coming out of that plastic box, you then have a potential path back to ground, and in fact, will likely have REAL ground connections. For example, many television sets have two wire power plugs, are in plastic cases, but if you have cable tv, the odds are that coax cable is grounded. Same thing applies if there is a telecom line involved -- very likely one of the telecom lines is ground. .. Mike Hopkins mhopk...@keytek.com -Original Message- From: Jim Hulbert [SMTP:hulbe...@pb.com] Sent: Wednesday, March 01, 2000 10:32 AM To: emc-p...@ieee.org Subject: Surge Testing per EN 55024/EN61000-4-5 Colleagues, EN 55024 calls for surge pulses to be applied line-to-line and line-to-earth on the AC mains port and line-to-ground on signal and telecommunications ports that connect directly to outdoor cables. However, if my EUT is encased in plastic covers and has no direct earth ground connection (class 2 power supply), is the line-to-line test on the AC mains the only surge test that I need to apply? It seems to me that performing a line-to-earth test on either the AC mains port or on signal/telecommunications ports is not warranted since the basic standard EN 61000-4-5 does not specify placing the EUT over a reference ground plane. With no reference ground plane and no direct ground connection how can a test be applied with respect to ground? Jim Hulbert Pitney Bowes - This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list adminstrators: Jim Bacher: jim_bac...@mail.monarch.com, or Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
