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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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PAT testing. Anyone else think that sometimes, it causes damage ?
Following on from my post of a couple of days ago, looking for a schematic
set for a JVC with a dead radio section, not having found one, I had a little search through my extensive stock of JVC manuals, and came up with one for a similar(ish) model of the same vintage, which used the same radio tuner sub-board. Using this, I was able to determine that all rails were established and correct, that the PLL chip was idling and unlocked, that the FM subsystem IC was idling, and that the VFD for the radio section had the correct supplies and drives, but was being 'muted' by the drive IC, which is also the system control processor. No I2C data was being sent to the PLL IC, hence the reason that it never ramped the tune voltage to the RF module. The I2C bus was however, correctly active for other control functions, such as handling the CD section. About the only conclusion that I could come to, was that either the microcontroller was in some subtle way faulty or, more likely I felt, its software was screwed. Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. I've never been a great believer in the appropriateness of applying these tests to double insulated and transformer based equipment, particularly given that large DC spikes are applied, which with some testers are actually twice the nominal line voltage. Given that in much microcontroller based electronic equipment, digital grounds are not directly bonded to other system grounds, it seems to me that having big voltage spikes flashing around between the primary side of the power supply, and cabinet metalwork, which is not grounded to any line power earth, but may well be AC common to internal DC grounds via low puff ( and sometimes not-so-low ) caps and high value resistors, is asking for trouble of the same nature as you might expect from static damage, or pulse damage from nearby lightning strikes. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. Arfa |
#2
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Arfa Daily" JVC midi size hi-fi system. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. ..... Phil |
#3
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Phil Allison" wrote in message ... "Arfa Daily" JVC midi size hi-fi system. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. .... Phil Well, to some extent, this is my point. I'm no expert on the regs, and it's my feeling that items such as this should not be subject to the high voltage tests for the very reasons that I suspect that it may cause damage to them. Possibly, they are not strictly speaking required to be tested, but several of the places that I do work for, have local authority customers, so care homes, schools, that sort of thing, and every item that I see from such establishments - including fully plastic cased boom-boxes - always has a "tested" sticker on it, with a date for the next test, so it's my belief that a shotgun approach for every item that runs off the mains, and is not bolted down, is being applied. And probably by the general maintenance man, who just has an automatic tester as part of his kit box, and a general mandate to use it ... Arfa |
#4
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PAT testing. Anyone else think that sometimes, it causes damage?
On 6/17/2010 4:20 AM, Arfa Daily wrote:
"Phil Allison" wrote in message ... "Arfa Daily" JVC midi size hi-fi system. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. .... Phil Well, to some extent, this is my point. I'm no expert on the regs, and it's my feeling that items such as this should not be subject to the high voltage tests for the very reasons that I suspect that it may cause damage to them. Possibly, they are not strictly speaking required to be tested, but several of the places that I do work for, have local authority customers, so care homes, schools, that sort of thing, and every item that I see from such establishments - including fully plastic cased boom-boxes - always has a "tested" sticker on it, with a date for the next test, so it's my belief that a shotgun approach for every item that runs off the mains, and is not bolted down, is being applied. And probably by the general maintenance man, who just has an automatic tester as part of his kit box, and a general mandate to use it ... Arfa Hello, As someone in the USA who has no idea of what you are speaking of, could you enlighten me as to what a PAT (particularly annoying test?)test is? Is it required of consumer goods? Regards, Tim Schwartz Bristol Electronics |
#5
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PAT testing. Anyone else think that sometimes, it causes damage ?
On Fri, 18 Jun 2010 07:39:54 -0400 Tim Schwartz wrote
in Message id: : On 6/17/2010 4:20 AM, Arfa Daily wrote: "Phil Allison" wrote in message ... "Arfa Daily" JVC midi size hi-fi system. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. .... Phil Well, to some extent, this is my point. I'm no expert on the regs, and it's my feeling that items such as this should not be subject to the high voltage tests for the very reasons that I suspect that it may cause damage to them. Possibly, they are not strictly speaking required to be tested, but several of the places that I do work for, have local authority customers, so care homes, schools, that sort of thing, and every item that I see from such establishments - including fully plastic cased boom-boxes - always has a "tested" sticker on it, with a date for the next test, so it's my belief that a shotgun approach for every item that runs off the mains, and is not bolted down, is being applied. And probably by the general maintenance man, who just has an automatic tester as part of his kit box, and a general mandate to use it ... Arfa Hello, As someone in the USA who has no idea of what you are speaking of, could you enlighten me as to what a PAT (particularly annoying test?)test is? Is it required of consumer goods? First hit on Google. http://en.wikipedia.org/wiki/PAT_Testing |
#6
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Phil Allison" wrote in message ... "Arfa Daily" JVC midi size hi-fi system. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. .... Phil Well, to some extent, this is my point. I'm no expert on the regs, and it's my feeling that items such as this should not be subject to the high voltage tests for the very reasons that I suspect that it may cause damage to them. Possibly, they are not strictly speaking required to be tested, but several of the places that I do work for, have local authority customers, so care homes, schools, that sort of thing, and every item that I see from such establishments - including fully plastic cased boom-boxes - always has a "tested" sticker on it, with a date for the next test, so it's my belief that a shotgun approach for every item that runs off the mains, and is not bolted down, is being applied. And probably by the general maintenance man, who just has an automatic tester as part of his kit box, and a general mandate to use it ... Arfa |
#7
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PAT testing. Anyone else think that sometimes, it causes damage ?
In article ,
Phil Allison wrote: ** Why on earth would a unit like that have to be PAT tested ???? Every mains powered electrical item has to be if used in the work place, etc. However, the procedure isn't the same for everything. No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. Australia ain't the world... -- *One of us is thinking about sex... OK, it's me. Dave Plowman London SW To e-mail, change noise into sound. |
#8
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PAT testing. Anyone else think that sometimes, it causes damage?
On 17/06/2010 11:15, Dave Plowman (News) wrote:
In , Phil wrote: ** Why on earth would a unit like that have to be PAT tested ???? Every mains powered electrical item has to be if used in the work place, etc. However, the procedure isn't the same for everything. No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. Nope. It's 5 Years in an "Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment" Australia PAT testing (they call it 'test and tag') does looks fairly similar, if not the same to the UK. For example, within Victoria the Occupation Health & Safety Act 2004 states: “An employer must, so far as reasonably practicable, provide and maintain for employees of the employer a working environment that is safe and without risk to health.” Exact same statement is in the UK H&S Act (probably no surprise there - we probably wrote it on paper first... ;-) The standard AS/NZS 3760 is referred as a way of implementing this. Here is the testing interval from that standard. http://policies.swinburne.edu.au/ppd...num=TEM/2009/7 In the UK however, we have a document published by the IET called "Code of Practice for In-Service Inspection and testing of electrical equipment" that recommends the following PAT testing schedule. It is a bit different ... http://www.linpat.co.uk/Suggested%20...%20Testing.htm Australia ain't the world... He doesn't live in the world ... -- Adrian C |
#9
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PAT testing. Anyone else think that sometimes, it causes damage?
On 17/06/2010 12:35, Adrian C wrote:
Nope. It's 5 Years in an "Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment" Sorry, that was aimed at the troll ... -- Adrian C |
#10
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Adrian C" Phil Allison ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. Nope. It's 5 Years in an "Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment" Australia PAT testing (they call it 'test and tag') does looks fairly similar, if not the same to the UK. ** This guide from WorkCover NSW makes it CLEAR that there is NO testing needed in this example. http://www.workcover.nsw.gov.au/form... ent_1336.pdf See item 7: " How often should I 'test and tag' my electrical equipment. " " For all other workplaces, the inspection and testing intervals are described in the standard, AS/NZS 3760 but ONLY need be applied to electrical equipment that has been assessed as operating in a hostile operating environment as described in clause 64 of the OHS Regulation." BTW: The issue here is PAT testing, I have no argument that regular visual inspections for damage or deterioration etc are needed under the OHS laws here. ..... Phil |
#11
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Phil Allison" wrote in message ... "Adrian C" Phil Allison ** Why on earth would a unit like that have to be PAT tested ???? No requirement exists here in Australia for low risk items used in non hazardous work environments to be regularly tested. Nope. It's 5 Years in an "Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment" Australia PAT testing (they call it 'test and tag') does looks fairly similar, if not the same to the UK. ** This guide from WorkCover NSW makes it CLEAR that there is NO testing needed in this example. http://www.workcover.nsw.gov.au/form... ent_1336.pdf See item 7: " How often should I 'test and tag' my electrical equipment. " " For all other workplaces, the inspection and testing intervals are described in the standard, AS/NZS 3760 but ONLY need be applied to electrical equipment that has been assessed as operating in a hostile operating environment as described in clause 64 of the OHS Regulation." BTW: The issue here is PAT testing, I have no argument that regular visual inspections for damage or deterioration etc are needed under the OHS laws here. .... Phil Agreed Arfa |
#12
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PAT testing. Anyone else think that sometimes, it causes damage?
On 18/06/2010 03:08, Phil Allison wrote:
** This guide from WorkCover NSW makes it CLEAR that there is NO testing needed in this example. http://www.workcover.nsw.gov.au/form... ent_1336.pdf See item 7: " How often should I 'test and tag' my electrical equipment. " " For all other workplaces, the inspection and testing intervals are described in the standard, AS/NZS 3760 but ONLY need be applied to electrical equipment that has been assessed as operating in a hostile operating environment as described in clause 64 of the OHS Regulation." OK, accepted. Didn't know about that 'code of practice' document. -- Adrian C |
#13
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PAT testing. Anyone else think that sometimes, it causes damage ?
Arfa Daily wrote in message
news:zNdSn.54051$Hs4.1013@hurricane... Following on from my post of a couple of days ago, looking for a schematic set for a JVC with a dead radio section, not having found one, I had a little search through my extensive stock of JVC manuals, and came up with one for a similar(ish) model of the same vintage, which used the same radio tuner sub-board. Using this, I was able to determine that all rails were established and correct, that the PLL chip was idling and unlocked, that the FM subsystem IC was idling, and that the VFD for the radio section had the correct supplies and drives, but was being 'muted' by the drive IC, which is also the system control processor. No I2C data was being sent to the PLL IC, hence the reason that it never ramped the tune voltage to the RF module. The I2C bus was however, correctly active for other control functions, such as handling the CD section. About the only conclusion that I could come to, was that either the microcontroller was in some subtle way faulty or, more likely I felt, its software was screwed. Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. I've never been a great believer in the appropriateness of applying these tests to double insulated and transformer based equipment, particularly given that large DC spikes are applied, which with some testers are actually twice the nominal line voltage. Given that in much microcontroller based electronic equipment, digital grounds are not directly bonded to other system grounds, it seems to me that having big voltage spikes flashing around between the primary side of the power supply, and cabinet metalwork, which is not grounded to any line power earth, but may well be AC common to internal DC grounds via low puff ( and sometimes not-so-low ) caps and high value resistors, is asking for trouble of the same nature as you might expect from static damage, or pulse damage from nearby lightning strikes. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. Arfa Now if it was actually a flash test not a pat test then who needs lightning. |
#14
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PAT testing. Anyone else think that sometimes, it causes damage ?
"N_Cook" wrote in message ... Arfa Daily wrote in message news:zNdSn.54051$Hs4.1013@hurricane... Following on from my post of a couple of days ago, looking for a schematic set for a JVC with a dead radio section, not having found one, I had a little search through my extensive stock of JVC manuals, and came up with one for a similar(ish) model of the same vintage, which used the same radio tuner sub-board. Using this, I was able to determine that all rails were established and correct, that the PLL chip was idling and unlocked, that the FM subsystem IC was idling, and that the VFD for the radio section had the correct supplies and drives, but was being 'muted' by the drive IC, which is also the system control processor. No I2C data was being sent to the PLL IC, hence the reason that it never ramped the tune voltage to the RF module. The I2C bus was however, correctly active for other control functions, such as handling the CD section. About the only conclusion that I could come to, was that either the microcontroller was in some subtle way faulty or, more likely I felt, its software was screwed. Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. I've never been a great believer in the appropriateness of applying these tests to double insulated and transformer based equipment, particularly given that large DC spikes are applied, which with some testers are actually twice the nominal line voltage. Given that in much microcontroller based electronic equipment, digital grounds are not directly bonded to other system grounds, it seems to me that having big voltage spikes flashing around between the primary side of the power supply, and cabinet metalwork, which is not grounded to any line power earth, but may well be AC common to internal DC grounds via low puff ( and sometimes not-so-low ) caps and high value resistors, is asking for trouble of the same nature as you might expect from static damage, or pulse damage from nearby lightning strikes. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. Arfa Now if it was actually a flash test not a pat test then who needs lightning. Well, who's to say that it's not getting one of these as well ? If such tests are being done by people who don't understand the implications ... I would say that there is also potential for metal cased items such as this, to get 'abused' by flash tests on metal boxed sockets as are often found in local authority buildings, if the item remains plugged in. I could easily see the metal case getting used as an 'earth' by someone who didn't realize that it's not. As far as they are concerned, it's probably just a big lump of metal plugged into the mains ! I might be completely wrong on all this. Just that over the years, I seem to have seen a lot of 'odd' faults that finally seem to come down to faulty uP chips, in items that carry a PAT test sticker with a very recent date on it. Arfa |
#15
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PAT testing. Anyone else think that sometimes, it causes damage?
On 17/06/2010 01:14, Arfa Daily wrote:
Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. Yup, PAT testing killed it, or correctly the incorrect procedure This would have been Class II double insulated, so a tester would have a choice of either a 'hard test' or 'soft test' to check the insulation resistance, as part of the test. The 'hard test' is a measurement of resistance (over 2Mohm ClassII) found using a test voltage of 500V DC applied between 1) L&N connected AND 2) any exposed possibly conductive surfaces (wandering probe) The 'soft test' is powering the thing up normally on supply, and using a wandering probe to measure any leakage current fron exposed possibly conductive surfaces. A 'hard test' is the thing for non-electronic equipment, 'soft' for everything else. However, the wizzy do-everything electronic testers make selecting soft and hard tests as easy as clicking a button, and mistakes can and do happen. I trained (C&G 2377) in doing this as a possible part/full time job, but the risks of blowing up perfectly OK equipment, plus the meagre earnings doing hundreds of items in an office, made me abandon the idea quite quickly. -- Adrian C |
#16
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Adrian C" wrote in message ... On 17/06/2010 01:14, Arfa Daily wrote: Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. Yup, PAT testing killed it, or correctly the incorrect procedure This would have been Class II double insulated, so a tester would have a choice of either a 'hard test' or 'soft test' to check the insulation resistance, as part of the test. The 'hard test' is a measurement of resistance (over 2Mohm ClassII) found using a test voltage of 500V DC applied between 1) L&N connected AND 2) any exposed possibly conductive surfaces (wandering probe) The 'soft test' is powering the thing up normally on supply, and using a wandering probe to measure any leakage current fron exposed possibly conductive surfaces. A 'hard test' is the thing for non-electronic equipment, 'soft' for everything else. However, the wizzy do-everything electronic testers make selecting soft and hard tests as easy as clicking a button, and mistakes can and do happen. I trained (C&G 2377) in doing this as a possible part/full time job, but the risks of blowing up perfectly OK equipment, plus the meagre earnings doing hundreds of items in an office, made me abandon the idea quite quickly. -- Adrian C OK Adrian. That's just the sort of detailed and informed input that I was looking for, and backs my feelings on the matter. I think I might mention this to the shop who took this item in, when I return it tomorrow. Arfa |
#17
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PAT testing. Anyone else think that sometimes, it causes damage?
Adrian C wrote in message
... On 17/06/2010 01:14, Arfa Daily wrote: Last week, we had a couple of claps of thunder locally, so I began to think that this might be a 'storm damage' job. Either way, in view of its age, it was not going to be a practical repair, so I informed the store that it came to me from, and put it back together. It was at this point that I noticed the PAT test label wrapped around its power lead, and this indicated that the test had been carried out only a week or so before it became faulty. At this point, I began wondering if the fact that it had had the tests performed on it, probably by someone with an automatic tester and little understanding of what it is doing, and where it is appropriate to run which tests, had resulted in damage to the microcontroller. I have seen other equipment on a number of occasions over the years, with similar 'odd' failures, and sometimes power supply failures, shortly after being PAT tested. Yup, PAT testing killed it, or correctly the incorrect procedure This would have been Class II double insulated, so a tester would have a choice of either a 'hard test' or 'soft test' to check the insulation resistance, as part of the test. The 'hard test' is a measurement of resistance (over 2Mohm ClassII) found using a test voltage of 500V DC applied between 1) L&N connected AND 2) any exposed possibly conductive surfaces (wandering probe) The 'soft test' is powering the thing up normally on supply, and using a wandering probe to measure any leakage current fron exposed possibly conductive surfaces. A 'hard test' is the thing for non-electronic equipment, 'soft' for everything else. However, the wizzy do-everything electronic testers make selecting soft and hard tests as easy as clicking a button, and mistakes can and do happen. I trained (C&G 2377) in doing this as a possible part/full time job, but the risks of blowing up perfectly OK equipment, plus the meagre earnings doing hundreds of items in an office, made me abandon the idea quite quickly. -- Adrian C What about 5KV or 10KV flash testers being used in the wrong situations? |
#18
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PAT testing. Anyone else think that sometimes, it causes damage?
On 17/06/2010 12:03, N_Cook wrote:
What about 5KV or 10KV flash testers being used in the wrong situations? Flash testing (AKA Dielectric Strength testing / Hi-POT testing) is done by manufacturers as part of their 'out the door' production checks. The IET code recommends NOT doing this as part of a user testing programme, for guidence will be required from the manufacturer for precautions applying the test AND the flash testing itself may encorage after failure of the insulation. -- Adrian C |
#19
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PAT testing. Anyone else think that sometimes, it causes damage?
Arfa Daily wrote:
(some content snipped) I've never been a great believer in the appropriateness of applying these tests to double insulated and transformer based equipment, particularly given that large DC spikes are applied, which with some testers are actually twice the nominal line voltage. Given that in much microcontroller based electronic equipment, digital grounds are not directly bonded to other system grounds, it seems to me that having big voltage spikes flashing around between the primary side of the power supply, and cabinet metalwork, which is not grounded to any line power earth, but may well be AC common to internal DC grounds via low puff ( and sometimes not-so-low ) caps and high value resistors, is asking for trouble of the same nature as you might expect from static damage, or pulse damage from nearby lightning strikes. I would be interested in knowing if I'm on my own on this one, or if anybody else involved professionally in service work - or indeed anyone who carries out PAT testing - has any similar experience, or opinions on this. Arfa I had to look up "PAT Testing" online. It sounds like yet one more unnecessary time-and-money-wasting government annoyance, like lead-free solder and banned cleaning solvents. I'm sure we in the USA will be doing that too, soon enough. At first glance, an incorrectly applied PAT sounds like a fine way to destroy MOV protection devices. |
#20
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PAT testing. Anyone else think that sometimes, it causes damage ?
"Mark Allread" I had to look up "PAT Testing" online. It sounds like yet one more unnecessary time-and-money-wasting government annoyance, like lead-free solder and banned cleaning solvents. I'm sure we in the USA will be doing that too, soon enough. At first glance, an incorrectly applied PAT sounds like a fine way to destroy MOV protection devices. ** MOVs are NOT connected from line to ground inside equipment sold in Europe or Australia - cos it is a very dangerous practice. In any case, the appliance tester only outputs a very small current to the device under test in order to measure leakage to frame or chassis and is not normally applied across the AC line terminals. ..... Phil |
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