Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Yes you are correct, in the UK it is enforced but there are ways that the wiring could be miss wired by DIY people etc, but they strictly should not be doing it if they don't know what they are doing, and certain jobs, such as replacing consumer units (distribution boards) are noticeable notifiable jobs where you have to notify the supply authorities the local authority's building control officers so that they can in theory come and approve your work for connection to their supply.

Buying a used house, the mortgage companies IIRC require a full electrical survey to be carried out before granting any money for the buyer etc. Selling a house the law requires that you provide a full current electrical inspection certificate to the buyer. I have done many wiring jobs for homeowners and many industrial ones as well in my working life and I have never come across any sockets that were not correctly wired. All terminals are very clearly labelled as to what they are.

There, fixed a whole bunch of things for you.

Thanks for updating me on the latest requirements in that respect. I do know however that it used to be the moneylenders who insisted on having a building survey done and an electrical survey and certification done. The government decided to shake things up a bit a few years ago, I dare say round about the time that brought in the Part P scheme as well I expect

[Zucca]

And the winner is Italy
Worst wiring and reversable 3 pin plug

Ciao Roberto, now sit back, relax and enjoy the reading.
I lived in Italy for 23 years, in Germany for 13 years and in USA for 4 years and counting.
This post reflect my daily experience with main plugs.

I am scared to death about this:


I did not travel in the entire globe, but to my knowledge it is hard to find something worst than the US/Canadian horror movie plug (and you know why, regardless its symmetric or not variant).
I'll take my messy italian plug (with it's no sense extra safety two sizes 10A and 15A) every day of the week instead of that US fireman nightmare plug.

According to your past posts you are very smart guy, it is not necessary to tell you the reasons and why it is like this.

Yes the german schuko is not perfect, but holy cow at least it pass my minimal safety standard.

Do not worries and I am not irritated, I am just telling my experience.

This is a tragic comic situation: North America with its most advanced countries in the world have the most retarded main plug.
Enjoy the movie of life.

and yes there is still hope!

[mnementh]

Always assume previous person was colour blind, normal blind and stupid

For electrical wiring or basically in general? 

Electrons are colour blind, they don't care the colour of the wire you touch

Better to assume this always; you'll suffer much less frustration in life. It helps if you can cultivate a general attitude of cynical observational detachment; then you'll be more often amused than aghast.

mnem
"Electrons may be very very tiny; but when they gang up on you, they always win." ~old man Kirsch, my High School Electronics / Machine Shop Instructor

[Kosmic]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set an auction listing scheduled to end at midnight on a holiday.



I wake up in the morning and realized I was the new owner of a slightly dysfunctional and really heavy Fluke 5101B Calibrator.



Look like I got one of the earlier unit built early 80 (serial num 2375003). The Analog Control and Power Amplifier boards have been replaced at the end of 90 or early 2000. Also I was surprised when I opened the instrument since I didn't know it was equipped with the optional wide band output. It can output an AC voltage up to 10MHz on the BNC connector in the front.

Close up on the voltage reference (LTFLU) and precision resistor sitting on the Analog Control board.


It was sold as broken and the listing was mentioning that the Calibrator was powering up but always outputting the double of what you were asking. Ex you punch-in 1V and get 2V. After some testing I realized this was not entirely true. The Calibrator was actually always outputting the max of his range.


After looking at the block diagram I figured that the problem was probably on the DAC board.


So the manual mention testing TP5, TP7 and TP10 for signal. Initially no waveforms were present on those test points. But after poking around with the oscilloscope probe on TP5 I realized that the whole thing started working when a 10Mohm load was bridging TP5 to ground.


I think U30 (NAND Gate) is damage and need to be changed. I don't fully understand why the 10Mohm load to ground make a difference. Increase voltage on the open collector output of U30 ? It also look like the optocouplers U32 and U38 were changed in the 90s.


So I will replace U30 but in the meanwhile I did a quick bodge to try to test the instrument.

I soldered a 15Mohm resistor between TP5 and ground 

[Cerebus]

13A fuses in the plugtops will see you long dead and are not safe at all they are a throwback solution to a ring main problem.

Which is complete nonsense. They are safe. In fact they are defence in depth. For faults downstream of the plug, if there's a fault with the plug top fuse, the central breaker will catch it, if there's a fault with the central breaker, the plug top fuse will catch it. If your single breaker fails, what's protecting you? Oh yeah, nothing but the smouldering wiring.

Moreover, they allow appliances to be fused at less than the breaker rating. Commonly available plug top fuses go down to 3A (1A is available), at which fault current the central breaker will just sit there and happily continue supplying current, feeding the fault if there wasn't a plug top fuse.

[Kosmic]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.

Missing pictures from previous post

The waveform on TP5 when everything is working correctly.


The 2 optocouplers on the DAC board.

[Zucca]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.

I like it, just be careful:

[capt bullshot]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.

Close up on the voltage reference (LTFLU) and precision resistor sitting on the Analog Control board.

Congrats! Very useful boat anchor this is.
Anyway, never seen that new analog control board with the LTFLU before. Mine has a selected zener / resistor and its stability is impressive anyway.

[Kosmic]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.

Close up on the voltage reference (LTFLU) and precision resistor sitting on the Analog Control board.

Congrats! Very useful boat anchor this is.
Anyway, never seen that new analog control board with the LTFLU before. Mine has a selected zener / resistor and its stability is impressive anyway.

Ha, this is why the manual doesn't list U10 as a LTFLU.

I could start a thread and post high rez pictures if there is some interest

[Cerebus]

So, my point is "there's a historical reason for the UK plugs to employ a fuse", and this requires the wall sockets to have a defined polarity because there's only one fuse in the plug. It's just a system that is different from mainland, an "island solution". Nothing wrong with either system, you'll have to know how to deal with it.

BS1363 introduced fused plugs as the standard in 1947. So there's little historical reason in the sense you're suggesting, as I expect that the number of operational 74 year old appliance cords is in pretty small numbers. The introduction of fused plugs was a deliberate effort to make electricity infrastructure safer not a mitigation for some existing state of affairs. As it stands now in the UK you are guaranteed four levels of protection between an appliance and the mains incomer - the company fuses (typ 100A), a main breaker (typ 63A), a circuit breaker (typ 30/32A), and a plug top or fixed outlet fuse (1-13A), plus earth leakage protection at least at the main breaker level.

[Robert763]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.


I wake up in the morning and realized I was the new owner of a slightly dysfunctional and really heavy Fluke 5101B Calibrator.


Look like I got one of the earlier unit built early 80 (serial num 2375003). The Analog Control and Power Amplifier boards has been replaced at the end of 90 or early 2000. Also I didn't know it was equipped with the optional wide band output. It can output an AC voltage up to 10MHz on the BNC connector in the front.


It was sold as broken and the listing was mentioning that the Calibrator was powering up but always outputting the double of what you were asking. Ex you punch-in 1V and get 2V. After some testing I realized this was not entirely true. The Calibrator was actually always outputting the max of his range.

After looking at the block diagram I figured that the problem was probably on the DAC board.


So the manual mention testing TP5, TP7 and TP10 for signal. Initially no waveforms were present on those test points. But after poking around with the oscilloscope probe on TP5 I realized that the whole thing started working when a 10Mohm load was bridging TP5 to ground.


I think U30 (NAND Gate) is damage and need to be changed. I don't fully understand why the 10Mohm load to ground make a difference. Increase voltage on the open collector output of U30 ? It also look like the optocouplers U32 and U38 were changed in the 90s.


So I will replace U30 but in the meanwhile I did a quick bodge to try to test the instrument.

I soldered a 15Mohm resistor between TP5 and ground 

More likely U32 has gone low gain / transfer ratio and needs that tiny bit more curent to drive it on.

[mnementh]

And the winner is Italy
Worst wiring and reversable 3 pin plug

Ciao Roberto, now sit back, relax and enjoy the reading.
I lived in Italy for 23 years, in Germany for 13 years and in USA for 4 years and counting.
This post reflect my daily experience with main plugs.

I am scared to death about this:

...This is a tragic comic situation: North America with its most advanced countries in the world have the most retarded main plug. Enjoy the movie of life.

and yes there is still hope!

We're so advanced our "Mental Health Care System" is to turn all the sociopaths out of the asylums and put them in Congress. We've turned "Healthcare" in general into a rending plant to separate the citizens from their property, resulting in the single greatest transfer of real estate and other wealth from the many to the few since the days of land grants to plantation owners. We've turned "Due Process" into a shield for the few against the rightful retribution of the many.

Is it any surprise our NEC is so convoluted...?

And yet, I'd still rather have our simple 15A star topology wiring than any of that clusterfuck I've seen for the last few pages... while still open to all sorts of abuse by the ignorant and willfully malicious, at least for the most part any fault will be isolated to a single circuit with its own circuit breaker and will take out only 2-3 outlets. With ring topology, one short can take down a dozen outlets/lighting circuits all over a structure.

And lets not think aboot the constant bitching I hear in here over gear getting beat to death by fist-sized mace-like plugs that are absolutely unnecessary with a 120V system. When I imagine trying to hook up a home theater/TV/media players or PC/monitor/speakers/random peripherals with a half dozen of those or even lugging that shit around in my laptop bag... it makes my balls ache just to think of it.

Yes, familiarity does breed contempt, and the fact it is harder to electrocute yourself (tho yes, still very possible) with 120VAC than 240VAC tends to make most 'merkins pretty blase' aboot the circuits in their home... but if you know what you're doing, and you can be arsed...

...you can make it just as safe as any other system. And not have to worry aboot your ex beating you to death with the power cord from your porn-delivery system laptop.

mnem
tzzzzt.

[capt bullshot]

So the manual mention testing TP5, TP7 and TP10 for signal. Initially no waveforms were present on those test points. But after poking around with the oscilloscope probe on TP5 I realized that the whole thing started working when a 10Mohm load was bridging TP5 to ground.


I think U30 (NAND Gate) is damage and need to be changed. I don't fully understand why the 10Mohm load to ground make a difference. Increase voltage on the open collector output of U30 ? It also look like the optocouplers U32 and U38 were changed in the 90s.


So I will replace U30 but in the meanwhile I did a quick bodge to try to test the instrument.

I soldered a 15Mohm resistor between TP5 and ground 

More likely U32 has gone low gain / transfer ratio and needs that tiny bit more curent to drive it on.

No.
As the output of the NAND gate switches between -20V and -15V / OC, the 15M to GND (0V) always takes current away from the LED. So IMO it's rather a compensation for increased output leakage of the NAND gate.

Anyway, the usage of optocouplers is interesting here. IIRC, my unit doesn't have any optocouplers at all, all isolation is done by these inductive couplers. In the early years of optocouplers, the inductive couplers were way more reliable.

[Kosmic]

Hooo Boy, I snipped a big one this time (35kg/77lbs) and it's a Fluke! Please remember me to never set auction listing scheduled to end a midnight on a holiday.

More likely U32 has gone low gain / transfer ratio and needs that tiny bit more curent to drive it on.

That's the part I don't understand. current should flow from -15V to U30 (opencollector connected to -20V). So connecting TP5 to ground with a 10M resistor is not changing things a lot for U32.

[Kosmic]

So the manual mention testing TP5, TP7 and TP10 for signal. Initially no waveforms were present on those test points. But after poking around with the oscilloscope probe on TP5 I realized that the whole thing started working when a 10Mohm load was bridging TP5 to ground.


I think U30 (NAND Gate) is damage and need to be changed. I don't fully understand why the 10Mohm load to ground make a difference. Increase voltage on the open collector output of U30 ? It also look like the optocouplers U32 and U38 were changed in the 90s.


So I will replace U30 but in the meanwhile I did a quick bodge to try to test the instrument.

More likely U32 has gone low gain / transfer ratio and needs that tiny bit more curent to drive it on.

No.
As the output of the NAND gate switches between -20V and -15V / OC, the 15M to GND (0V) always takes current away from the LED. So IMO it's rather a compensation for increased output leakage of the NAND gate.

Anyway, the usage of optocouplers is interesting here. IIRC, my unit doesn't have any optocouplers at all, all isolation is done by these inductive couplers. In the early years of optocouplers, the inductive couplers were way more reliable.

That was also my conclusion. Thank you for confirming.

[capt bullshot]

So, my point is "there's a historical reason for the UK plugs to employ a fuse", and this requires the wall sockets to have a defined polarity because there's only one fuse in the plug. It's just a system that is different from mainland, an "island solution". Nothing wrong with either system, you'll have to know how to deal with it.

BS1363 introduced fused plugs as the standard in 1947. So there's little historical reason in the sense you're suggesting, as I expect that the number of operational 74 year old appliance cords is in pretty small numbers. The introduction of fused plugs was a deliberate effort to make electricity infrastructure safer not a mitigation for some existing state of affairs. As it stands now in the UK you are guaranteed four levels of protection between an appliance and the mains incomer - the company fuses (typ 100A), a main breaker (typ 63A), a circuit breaker (typ 30/32A), and a plug top or fixed outlet fuse (1-13A), plus earth leakage protection at least at the main breaker level.

OK, thanks for the explanation, "historical reason" interpreted as mitigation was the wrong term. It's part of the system design, historically, from the beginning of the system on.

[vk6zgo]

Buying a used house, the mortgage companies IIRC require a full electrical survey to be carried out before granting any money for the buyer etc. I have done many wiring jobs for homeowners and many industrial ones as well in my working life and I have never come across any sockets that were not correctly wired. All terminals are very clearly labelled as to what they are.

I have never come across outlets wired incorrectly if they were originally done by a sparky. I HAVE come across outlets wired backwards by someone who had no business doing electrical work.

Many years ago, I got bounced on my bum off a ladder from an outlet wired by a sparky.

We were installing CCTV cameras, mounted on pan/tilt heads which were, interestingly, operated by raw mains.
Limits had to be set individually with these, as in some places, they could bash the lens into some hard object, like the wall!

To this end, there were stops which had to be set inside each pan/tilt head.
So we didn't have to run back & forth from the control room, one of the "clever chaps" made up a box with two large key switches, which could be plugged into one of the GPOs conveniently mounted on pillars throughout the building.

We could then, with side of the device open, motor it to the required limit position, then adjust the limit switches.

For some reason, the internal (assumed) Neutral connections to the device were not insulated, & when I adjusted those units with a correctly wired GPO all was well, but when we used the one where the Active & Neutral were reversed, I got a nice shock, & fell off the ladder.
In fairness, if the "clever chap's" box had used double pole switches instead of single pole, or the device I was adjusting wasn't so cramped inside so I was less likely to brush a "hot bit", I would still have been safe.

Instead, everything went the other way, & I landed on my bum!

[shakalnokturn]

Here in the UK there is a correct way of wiring up sockets and it is the wiring regulations that the polarity is supposed to be checked when wiring has been done and we have special test plugs that are plugged into sockets and then the LED's on them will show if it is correctly wired, i.e., Live  to live, Neutral to neutral etc. and this test is supposed to be carried and a test report / certificate issued per installation before allowing anyone else to use the installation.

Oh OK ! So it's actually enforced in the UK, good to know. That's a nifty little device ! 

However that's only good for new houses, but then once you move in, nobody knows what you do at week-ends... if you mess with your system the next owners of the house won't know... OK let me guess, when you sell a house there is a legal requirement that you get every outlet tested and hand over the report to the potential buyer ? That's cool...

As for France nobody gives a shit of wiring at the outlets. Even on a new house, even though the house is SUPPOSED to be tested/certified before you can move in.... in practice, I was told by my house builder and the electricians I met that worked on my house, that the body in charge of checking all new houses, were understaffed and that in practice they actually checked only about one in 4 houses. For the other 3, they trust the builder's electricians... and just issue the "Tested good" paper without actually even seeing the house. It's just a piece of paper that's all 

Then for USED houses, well nobody gives a shit, no inspection required when you buy one, it's up to the buyer to redo anything he doesn't like, if he feels like it...

I guess it only becomes a problem if people die or the house burns to the ground. Then either the police and/or the insurance companies may want to dig further and blame X or Y for what happened. But other than that...

When getting my electrician's qualification in 2011 we were taught that the French sockets are meant to be wired to have earth on top, neutral to the left, live to the right when facing the socket. In the real world never assume...

I'd also say that the UK are the safest (although slightly paranoid) with their individual switches and fuses, of course those won't stop anyone from wiring the neutral to the switch/fuse...

On your Tek curve tracer I was joking of course... It's hard to assume whether the fuse will be on live or neutral in practice and if it is wired with bare wire on the neutral you're not at risk to touch it until the fuse goes, then all that is on the apparatus side of the fuse is live as far as fingers are concerned... Anyway this was not true in your example because the bare wire is between the recessed plug and fuse holder.

[mnementh]

So the manual mention testing TP5, TP7 and TP10 for signal. Initially no waveforms were present on those test points. But after poking around with the oscilloscope probe on TP5 I realized that the whole thing started working when a 10Mohm load was bridging TP5 to ground.


I think U30 (NAND Gate) is damage and need to be changed. I don't fully understand why the 10Mohm load to ground make a difference. Increase voltage on the open collector output of U30 ? It also look like the optocouplers U32 and U38 were changed in the 90s.


So I will replace U30 but in the meanwhile I did a quick bodge to try to test the instrument.

More likely U32 has gone low gain / transfer ratio and needs that tiny bit more curent to drive it on.

No.
As the output of the NAND gate switches between -20V and -15V / OC, the 15M to GND (0V) always takes current away from the LED. So IMO it's rather a compensation for increased output leakage of the NAND gate.

Anyway, the usage of optocouplers is interesting here. IIRC, my unit doesn't have any optocouplers at all, all isolation is done by these inductive couplers. In the early years of optocouplers, the inductive couplers were way more reliable.

That was also my conclusion. Thank you for confirming.

Is it possible these problems are a secondary effect of the mixing of boards from late model donor to an early model unit...? Possibly "retrofit mods" that would be part of a factory service procedure that never happened because the boards were changed by someone who didn't know better...?

mnem

[Cerebus]

So we didn't have to run back & forth from the control room, one of the "clever chaps" made up a box with two large key switches, which could be plugged into one of the GPOs conveniently mounted on pillars throughout the building.

I want to know how you got the whole of the General Post Office onto a pillar. I mean, that's going to be 10s of 1000s of people!

Or put differently - GPO is not a universal abbreviation and I haven't a clue what you're talking about. Abbreviations for bits of electrical kit do not, in general, travel well. e,g, UK abbreviations RCD, RCBO, ELCB.

[Robert763]

And the winner is Italy
Worst wiring and reversable 3 pin plug

Ciao Roberto, now sit back, relax and enjoy the reading.
I lived in Italy for 23 years, in Germany for 13 years and in USA for 4 years and counting.
This post reflect my daily experience with main plugs.

I am scared to death about this:


I did not travel in the entire globe, but to my knowledge it is hard to find something worst than the US/Canadian horror movie plug (and you know why, regardless its symmetric or not variant).
I'll take my messy italian plug (with it's no sense extra safety two sizes 10A and 15A) every day of the week instead of that US fireman nightmare plug.

According to your past posts you are very smart guy, it is not necessary to tell you the reasons and why it is like this.

Yes the german schuko is not perfect, but holy cow at least it pass my minimal safety standard.

Do not worries and I am not irritated, I am just telling my experience.

This is a tragic comic situation: North America with its most advanced countries in the world have the most retarded main plug.
Enjoy the movie of life.

and yes there is still hope!

But he NEMA plug is not 3 pin and reversable. Which was what I was refering to.
What's so wrong with the NEMA plug other than unsleeved pins?

[Cerebus]

Almost forgot. New screwdrivers arrived in the post today - ordered when I posted that 'heads up' the other day.

[Specmaster]

<snip>
BTW - did you notice the European tester fits both ways into the wall socket. So if it shows "L / N swapped", just turn it around and it'll show OK. Still useful for checking, anyway.

Yes I did notice that, but if you look at the UK tester, it also indicates precisely the same thing. That indicates to me that there is indeed a "correct or recommended" way to wire up your sockets, and that suggests to me that the correct way to use the European tester is with the writing in the correct plan, not upside down.

This is further reinforced by these photos I have found online that shows when looking at the terminal side, the Hot / LIVE should be in the left terminal, NEUTRAL in the right terminal and P/E or GROUND in the middle terminal. That means in a correctly wired installation when looking at the socket installed, from the user perspective, the NEUTRAL is the left hole and the HOT / LIVE is the right hole, exactly as it is for the UK.

I notice that only the UK socket has safety in mind for the installer as well with shrouded terminals 

[McBryce]

So which hole is the left hole on these sockets?

McBryce.

[Cerebus]

I notice that only the UK socket has safety in mind for the installer as well with shrouded terminals 

I think that is now required, it didn't used to be and I've seen some very sketchy BS1363 wall plates in my time.