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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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help sought - fuse for digital multimeter
Hi, I am an electronics newbie and owing to my own
stupidity I need a new fuse for my multimeter. Maplins say they are waiting for the right fuses to arrive from the Far East. My question is, do I really need the specific fuse they recommend, or can I use another one instead? The meter is a UT-70A (digital) by Unitrend. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. Maplins say the only fuse that will do is the one with their product code N65CA. I would be grateful if someone could tell me whether another fuse would be OK - i.e. one that I might actually get hold of tomorrow rather than waiting for indefinitely! I only use the meter for hobby electronics, so if the fuse blows at 400mA instead of 500mA, that would be OK with me. But I don't know what other specifications it might be stupid to ignore. Especially given that only a small number of fuses appear to be recommended for use in multimeters. Many thanks, Chris |
#2
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Chris Nellist wrote:
Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. Go to your nearest TV repair shop he'll supply you with one. :-) but make it worthwhile for him, buy half a dozen. |
#3
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"ben" wrote in message .uk... Chris Nellist wrote: Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. Go to your nearest TV repair shop he'll supply you with one. :-) but make it worthwhile for him, buy half a dozen. And don't try to measure amps in the mains again ;-) |
#4
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Hi, I am an electronics newbie and owing to my own
stupidity I need a new fuse for my multimeter. Not measuring voltages on the amps range again? ;-) The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. Very easy to find. Buy quickblow rather than surge/delay, unless you find instructions to the contrary. Maplins say the only fuse that will do is the one with their product code N65CA. ********. Christian. |
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Chris Nellist wrote:
My question is, do I really need the specific fuse they recommend, or can I use another one instead? You need the right rating. I can't think of any reason you need a special "multimeter fuse" (if there is such a thing) unless it is a non standard physical size. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. How about: http://cpc.farnell.com/jsp/endecaSea...=FF00332&N=411 Maplins say the only fuse that will do is the one with their product code N65CA. Could be because they don't list 500mA 20mm glass fuses in their fuses section. So in a sense that may be the only one they do that is suitable. I would be grateful if someone could tell me whether another fuse would be OK - i.e. one that I might actually get hold of tomorrow rather than waiting for indefinitely! I would have no worries about substituting the CPC part I linked to above. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#6
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This just shows the state of Electronics and the NUMPTIES that are in
the business. Not you for blowing the fuse while measuring Amps, but the NUMPTIES in the shop. I've just noticed my Fluke fuse has blown this morning, can't remember when I last measured mA. It is 5mm. dia. and 20mm. long. My Fluke says 2A. maximum on the Amps input. Just adjust yer fuse to suit the full scale. Chris. |
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wrote:
This just shows the state of Electronics and the NUMPTIES that are in the business. Not you for blowing the fuse while measuring Amps, but the NUMPTIES in the shop. As I think I mentioned before, a recent visit to a Maplin [1] branch elicited a question from the sprog behind the counter: "what is a grommet for?" when I tried to buy one! [1] The almost original branch in Westcliff (it moved 100yards down the road to new premises a few years back) where they used to employ well clued up electronics graduates who would think nothing of designing a quick circuit for the people who walked in off the street and said "how can I do something like....?" -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#8
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On Fri, 09 Sep 2005 16:05:15 +0100, John Rumm
wrote: As I think I mentioned before, a recent visit to a Maplin [1] branch elicited a question from the sprog behind the counter: "what is a grommet for?" when I tried to buy one! Next time ask for a hammerfour. John Schmitt -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ |
#9
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"John Rumm" wrote in message
... [1] The almost original branch in Westcliff (it moved 100yards down the road to new premises a few years back) where they used to employ well clued up electronics graduates who would think nothing of designing a quick circuit for the people who walked in off the street and said "how can I do something like....?" Personally, I'm glad that our economy is no longer so crap that decent electronics graduates are working in chain-stores. Will |
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The manual says get an "identical" fuse, then gives
a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. Might the following be suitable? Ebay.co.uk item number 7545314889 (no connection with the seller) Owain |
#11
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On 9 Sep 2005 14:16:34 GMT, Chris Nellist wrote:
one that I might actually get hold of tomorrow If you need it tomorrow, use a strand of wire. But don't repeat what you did when you blew it! -- Nigel M |
#12
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"Will Dean" wrote in message .. . "John Rumm" wrote in message ... [1] The almost original branch in Westcliff (it moved 100yards down the road to new premises a few years back) where they used to employ well clued up electronics graduates who would think nothing of designing a quick circuit for the people who walked in off the street and said "how can I do something like....?" Personally, I'm glad that our economy is no longer so crap that decent electronics graduates are working in chain-stores. Will I know some that work in Boots? Mind degrees are becoming like confetti! |
#13
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On Fri, 9 Sep 2005 16:18:03 +0100, "Will Dean"
wrote: "John Rumm" wrote in message ... [1] The almost original branch in Westcliff (it moved 100yards down the road to new premises a few years back) where they used to employ well clued up electronics graduates who would think nothing of designing a quick circuit for the people who walked in off the street and said "how can I do something like....?" Personally, I'm glad that our economy is no longer so crap that decent electronics graduates are working in chain-stores. You're surely not implying that our electronics industry is flourishing, and electronics graduates can reasonably expect to get high quality work in their own field, that went out in the '60s +'70s http://www.wsws.org/articles/2002/ju...wein-j27.shtml googling for weinstock and closure got me 15,600 hits. DG |
#14
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"Chris Nellist" wrote in message ... Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. Maplins say they are waiting for the right fuses to arrive from the Far East. My question is, do I really need the specific fuse they recommend, or can I use another one instead? The meter is a UT-70A (digital) by Unitrend. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. Maplins say the only fuse that will do is the one with their product code N65CA. I would be grateful if someone could tell me whether another fuse would be OK - i.e. one that I might actually get hold of tomorrow rather than waiting for indefinitely! I only use the meter for hobby electronics, so if the fuse blows at 400mA instead of 500mA, that would be OK with me. But I don't know what other specifications it might be stupid to ignore. Especially given that only a small number of fuses appear to be recommended for use in multimeters. Many thanks, Chris May I suggest www.farnell.com 532861 This is a ceramic fuse and so will cope with more nasty faults and protect you better. |
#15
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"Sparks" wrote in news:43219b36$0$38044$bed64819
@news.gradwell.net: And don't try to measure amps in the mains again ;-) Us old Plessey AVO8 needlebenders used to ferget to go off the 50 µA range before going back to the real world of HT. Good cutout, but not *that* good. mike |
#16
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In message , Chris Nellist
writes Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. So you just need a 20mm 500mA fuse Does it have an "F" or a "T" on it to indicate fast or slow blow ? Maplins should have those in stock, as for exact replacement, they're just covering their arses -- geoff |
#17
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In message , John
Rumm writes Chris Nellist wrote: My question is, do I really need the specific fuse they recommend, or can I use another one instead? You need the right rating. I can't think of any reason you need a special "multimeter fuse" (if there is such a thing) unless it is a non standard physical size. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. How about: http://cpc.farnell.com/jsp/endecaSea...=FF00332&N=411 Maplins say the only fuse that will do is the one with their product code N65CA. Could be because they don't list 500mA 20mm glass fuses in their fuses section. So in a sense that may be the only one they do that is suitable. I would be grateful if someone could tell me whether another fuse would be OK - i.e. one that I might actually get hold of tomorrow rather than waiting for indefinitely! I would have no worries about substituting the CPC part I linked to above. Cost of 5 fuses -70p ? cost of delivery ... what, a fiver ? (I have never placed an order under the free delivery amount, and end up with loads of crap which I never use) -- geoff |
#18
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In message , James
Salisbury writes "Chris Nellist" wrote in message ... I only use the meter for hobby electronics, so if the fuse blows at 400mA instead of 500mA, that would be OK with me. But I don't know what other specifications it might be stupid to ignore. Especially given that only a small number of fuses appear to be recommended for use in multimeters. Many thanks, Chris May I suggest www.farnell.com 532861 This is a ceramic fuse and so will cope with more nasty faults and protect you better. Again what's the delivery charge ? Doh He could prolly buy another meter for the cost of delivery from Farnell or CPC -- geoff |
#19
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raden wrote in :
In message , Chris Nellist writes Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. So you just need a 20mm 500mA fuse Does it have an "F" or a "T" on it to indicate fast or slow blow ? Yes - an "F". It has got "F500mAL250V". Maplins should have those in stock, as for exact replacement, they're just covering their arses Having looked again at the catalogue, I think the GJ87U would fit the bill. I'd be very grateful if someone could confirm! (This would avoid me having to pay shipping costs to Farnell's for such a cheap component). http://www.maplin.co.uk/Module.aspx?...=25433&doy=9m9 For some reason the Maplin's person on the phone told me this had a voltage rating of 60V, whereas it's actually 250V. Not that I plan on going near potential differences anything like as high as 60V. Thanks to everyone for replies and help. Chris |
#20
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In message , Chris Nellist
writes raden wrote in : In message , Chris Nellist writes Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. The manual says get an "identical" fuse, then gives a colon, and specifies 250V and 500mA. It also says phi5X20(mm), which I assume just means 5mm in diameter and 20mm long. So you just need a Fast blow 20mm 500mA fuse Does it have an "F" or a "T" on it to indicate fast or slow blow ? Yes - an "F". It has got "F500mAL250V". Maplins should have those in stock, as for exact replacement, they're just covering their arses Having looked again at the catalogue, I think the GJ87U would fit the bill. I'd be very grateful if someone could confirm! (This would avoid me having to pay shipping costs to Farnell's for such a cheap component). Yeah - some people seem to have lost the sense of proportion of the delivery costs vs the cost of such a cheap item http://www.maplin.co.uk/Module.aspx?...=25433&doy=9m9 For some reason the Maplin's person on the phone told me this had a voltage rating of 60V, whereas it's actually 250V. I'm not an expert on fuses, but the fuse rating is a function of current and time. Although most 20mm fuses I see are 250v rated, I don't see the relevance, especially if it's hidden inside a multimeter go for it Not that I plan on going near potential differences anything like as high as 60V. Thanks to everyone for replies and help. Chris -- geoff |
#21
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raden wrote in :
In message , Chris Nellist writes raden wrote in : In message , Chris Nellist writes .... Having looked again at the catalogue, I think the GJ87U would fit the bill. I'd be very grateful if someone could confirm! (This would avoid me having to pay shipping costs to Farnell's for such a cheap component). Yeah - some people seem to have lost the sense of proportion of the delivery costs vs the cost of such a cheap item http://www.maplin.co.uk/Module.aspx?...=25433&doy=9m9 For some reason the Maplin's person on the phone told me this had a voltage rating of 60V, whereas it's actually 250V. I'm not an expert on fuses, but the fuse rating is a function of current and time. Although most 20mm fuses I see are 250v rated, I don't see the relevance, especially if it's hidden inside a multimeter go for it Many thanks! That's me sorted! Chris |
#22
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Chris Nellist wrote:
Hi, I am an electronics newbie and owing to my own stupidity I need a new fuse for my multimeter. Then why not make a resetable electronic fuse? there's ample room in a meter to fit one in circuit. Plenty of books in the library or online for this sort of stuff. When I used to repair TV/Videos fuses became an expensive game when it came to locating faults and just when you thought you solved the problem the ruddy fuse would blow. So i made an electronic fuse to combat this till I knew the fault was solved. |
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Will Dean wrote:
Personally, I'm glad that our economy is no longer so crap that decent electronics graduates are working in chain-stores. Don't think that was the case then. Maplin was not a chain store then - that shop in Westcliff was the whole empire (we are talking '79/80 ish here - remeber the catlogue with concord on the front?). There was usually one pre-graduate doing a "year out" type of thing - but the rest were electronics enthusiasts who seemed to like working there. With regard to positions for electronics grads these days - I would say there are far less than in the early 80s. Software has crept into and replaced many of the traditional electronic engineering places, and analogue or high power RF work is very much reduced. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#24
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John Schmitt wrote:
Next time ask for a hammerfour. or a dickfour... ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#25
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Chris Nellist wrote:
Having looked again at the catalogue, I think the GJ87U would fit the bill. I'd be very grateful if someone could confirm! (This would avoid me having to pay shipping costs to Farnell's for such a cheap component). http://www.maplin.co.uk/Module.aspx?...=25433&doy=9m9 Yup that looks OK. It seems odd they don't list that in their 20mm glass fuse section... (Still the catalogue has never been the same since they took all the pinouts out of the IC section! ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#26
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In article ,
Chris Nellist wrote: Maplins say the only fuse that will do is the one with their product code N65CA. That's a 25mm (1in) Standard types are 20mm and 1 1/4in. -- *Virtual reality is its own reward* Dave Plowman London SW To e-mail, change noise into sound. |
#27
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In article .com,
wrote: I've just noticed my Fluke fuse has blown this morning, can't remember when I last measured mA. It is 5mm. dia. and 20mm. long. My Fluke says 2A. maximum on the Amps input. Just adjust yer fuse to suit the full scale. You seen the prices of genuine Fluke fuses? -- *Filthy stinking rich -- well, two out of three ain't bad Dave Plowman London SW To e-mail, change noise into sound. |
#28
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Mike,............... 'ave you seen the price of an AVO these days?
They're over 500 Quid. I just don't know how they can knock 'em out for that price. Chris |
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#30
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mike ring wrote:
You sure? I had to have a look and prices seem to vary from about 65 to 225? Not if you are talking the "original" model 8. Have a look at RS stock code 653-020.... £700 quid exc VAT for the basic model. Another 50 if you want it calibrated! They want £109 extra on top of that for the case. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#31
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In article ,
John Rumm wrote: Not if you are talking the "original" model 8. Have a look at RS stock code 653-020.... £700 quid exc VAT for the basic model. Another 50 if you want it calibrated! They want £109 extra on top of that for the case. They do, however, turn up on Ebay regularly often in mint condition. Go for maybe 150 quid. -- *Why do we say something is out of whack? What is a whack? Dave Plowman London SW To e-mail, change noise into sound. |
#32
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Dave Plowman (News) wrote:
Not if you are talking the "original" model 8. Have a look at RS stock code 653-020.... £700 quid exc VAT for the basic model. Another 50 if you want it calibrated! They want £109 extra on top of that for the case. They do, however, turn up on Ebay regularly often in mint condition. Go for maybe 150 quid. Must admit I have never quite understood the big attraction with Avos. Yes OK they are class 1 accuracy, and have a nice big meter movement, but are they really *that* good to command such a price? Or is there something they will do (besides keep heavy doors proped open) that I have missed? -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#33
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In article ,
John Rumm wrote: They do, however, turn up on Ebay regularly often in mint condition. Go for maybe 150 quid. Must admit I have never quite understood the big attraction with Avos. Yes OK they are class 1 accuracy, and have a nice big meter movement, but are they really *that* good to command such a price? Or is there something they will do (besides keep heavy doors proped open) that I have missed? They were simply the UK industry standard. Although I do have one it rarely gets used - I've got a smaller Taylor for things where a simple analogue meter might help diagnosis. -- *Beauty is in the eye of the beer holder... Dave Plowman London SW To e-mail, change noise into sound. |
#34
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In message , "Dave Plowman (News)"
wrote In article , John Rumm wrote: They do, however, turn up on Ebay regularly often in mint condition. Go for maybe 150 quid. Must admit I have never quite understood the big attraction with Avos. Yes OK they are class 1 accuracy, and have a nice big meter movement, but are they really *that* good to command such a price? Or is there something they will do (besides keep heavy doors proped open) that I have missed? They were simply the UK industry standard. I think the operative word is 'were'. They were outclassed on performance twenty years ago. The price probably doesn't reflect the quality of the meter but the cost of the calibration and the tractability back to standards. The average 'certified' electrician will be paying £100s to get their existing equipment calibrated each year. -- Alan |
#35
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In article ,
Alan wrote: Must admit I have never quite understood the big attraction with Avos. Yes OK they are class 1 accuracy, and have a nice big meter movement, but are they really *that* good to command such a price? Or is there something they will do (besides keep heavy doors proped open) that I have missed? They were simply the UK industry standard. I think the operative word is 'were'. They were outclassed on performance twenty years ago. For many AC measurements - or anything which required a high impedance device - many more years earlier. I've got a homemade (Heathkit) valve voltmeter which is over 30 years old. The price probably doesn't reflect the quality of the meter but the cost of the calibration and the tractability back to standards. It's just the cost of making something so old fashioned. The average 'certified' electrician will be paying £100s to get their existing equipment calibrated each year. I've got some ways of calibrating DVMs, and they don't drift that much - if well made. In some ways, calibration is a bit like CORGI etc membership. Just to satisfy the suits. -- *All those who believe in psychokinesis, raise my hand * Dave Plowman London SW To e-mail, change noise into sound. |
#36
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In message , "Dave Plowman (News)"
wrote I've got some ways of calibrating DVMs, While you may have some accurate ways of calibrating (or checking the calibration of) a multi-meter I guess the average electrician doesn't. Was that resistance measurement really 2 ohms or was it actually 4 ohms but with a partially fried ranging component? and they don't drift that much - if well made. If not subjected to (accidental) abuse the underlying DVM part of the equipment may not drift that much in a well made piece of modern equipment. Any form of accidental abuse may outwardly give an indication that no damage has been done because the meter still gives a reading but one or more of the ranges may be widely inaccurate. How many electricians are proclaiming installations are safe and are writing certificates while still using equipment that has never been checked for accuracy since they purchased it. In some ways, calibration is a bit like CORGI etc membership. Just to satisfy the suits. In some respects yes, if taken to the extreme , but also regard a regular calibration in the same way a road vehicle MOT test. Many faults are not identified until someone else checks out the equipment. -- Alan |
#37
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In message , Alan
writes In message , "Dave Plowman (News)" wrote I've got some ways of calibrating DVMs, While you may have some accurate ways of calibrating (or checking the calibration of) a multi-meter I guess the average electrician doesn't. Was that resistance measurement really 2 ohms or was it actually 4 ohms but with a partially fried ranging component? How often would a sparkie want to measure more than whether 230V was there or not with a DVM ? -- geoff |
#38
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In message , raden
wrote In message , Alan writes In message , "Dave Plowman (News)" wrote I've got some ways of calibrating DVMs, While you may have some accurate ways of calibrating (or checking the calibration of) a multi-meter I guess the average electrician doesn't. Was that resistance measurement really 2 ohms or was it actually 4 ohms but with a partially fried ranging component? How often would a sparkie want to measure more than whether 230V was there or not with a DVM ? Do you mean that they don't actually do earth bonding tests etc. It may not be performed with the £4 LIdl special offer DVM but it should be with equipment that is calibrated if they are going to issue a certificate saying that the installation is safe.. -- Alan |
#39
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"Alan" wrote in message ... In some respects yes, if taken to the extreme , but also regard a regular calibration in the same way a road vehicle MOT test. Many faults are not identified until someone else checks out the equipment. Not sure if that's a good analogy. A good car mechanic will have some sympathy with the car and sort important things out before an MOT. Recovery vehicles are exempt from MOTs. |
#40
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In article ,
Alan wrote: If not subjected to (accidental) abuse the underlying DVM part of the equipment may not drift that much in a well made piece of modern equipment. Any form of accidental abuse may outwardly give an indication that no damage has been done because the meter still gives a reading but one or more of the ranges may be widely inaccurate. How many electricians are proclaiming installations are safe and are writing certificates while still using equipment that has never been checked for accuracy since they purchased it. Well, yes. But assuming that damage happened just after annual calibration and certification there could be many many installations not checked correctly. At one time the accurately calibrated speedometers in police traffic cars where checked for calibration daily... -- *Experience is something you don't get until just after you need it.* Dave Plowman London SW To e-mail, change noise into sound. |
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