Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

If on the other hand as others have indicated there no legal requirements for which pin the Hot and Neutral wires are terminated at, then that is a recipe for problems.

Why?

I believe that there must be some standard that electricians have to conform to and that the connections of sockets are clearly defined as to what each is supposed to connected to, so that anything that demands a ground connection for safety can only be connected one way when the plug is plugged in, so that the switch on the equipment and any fuse in the equipment is in the Hot or Live line so that in the even of a problem, the fuse isolates the incoming supply to prevent the metal work on the equipment remaining connected to the Live and still present a dangerous situation.

Anything that is double insulated, such as a plastic cased drill, fan etc, and does not have any requirement for a ground connection or fuse, should be connected to a plug which is not polarised.

Anything else just does not compute on safety grounds, and why would manufacturers make dedicated socket testers if there was no legal requirement for correct wiring connections to the socket terminals.

Here is a UK socket tester.



Here is a European tester

[med6753]

After reading the last few posts you guys still think North America (USA/Canada) mains wiring is fucked up?

I think not. 

[xrunner]

Page 4060. There is a device but I don't have it ... 

[BU508A]

My socket tester:



Benning Duspol Type S

[Specmaster]

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...

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 jobs where you have to notify the supply authorities so that they can 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. 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.

[Specmaster]

My socket tester:



Benning Duspol Type S

That is no more than a volt meter really, the fact that you can use it to see if a socket is wired correctly is down to your skill in using, where as a proper socket tester put that skill into the hands of unskilled people, they cannot get it wrong. You on the other hand can still make a mistake and miss out certain testing combinations by accident.

[med6753]

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.

[bd139]

LMAO that’s horrible. That’s got to be at least 50A that fuse 

Fun job of the evening. Not. Trying to build 300Hz RBW filter for my SA. This unfortunately requires me to build a half decent crystal filter which means matching a shit ton of crystals by hand then characterising them further later. Frequency binning in progress 

Aren't those crystals already marked with their frequencies then? All of mine are, although I have checked them, but they were all correctly marked already?

Yep. 4.9152 MHz with 30pF loading.

That’s fine for oscillators but not for filters! The motional parameters of the crystals are all slightly different so they can vary in the same fixture by up to 100Hz or so. To get a fairly ripple free narrow filter I need really tight matching between them. Ideally I need to find 8 within 5Hz or so with close Lm and Cm.

This is unfortunately why I’ve got a bag of 200 to go through to select some by hand.

This is also why crystals are a few pence each but crystal filters are £100+ 

I've got a Saunders crystal imedance meter.....
https://prc68.com/I/CrystalImpedanceMeters.html
You could make a trip worthwhile 

Tempting. Very tempting! 

Still need to contact you. Sorry for delay - wrangling large IT migration at the moment so not sure what schedule is looking like yet.

[Specmaster]

After reading the last few posts you guys still think North America (USA/Canada) mains wiring is fucked up?

I think not. 

I'm only going by the American gear that I have seen over here, fitted with a 2 pin plug.

[bd139]

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.

My sparky has no business doing electrical work 

[Cerebus]

The British "13A" plug is probably the safest designs out there. The EU tried to make a common system but had to accepet the lowest standard so non-polarised.
Polarised is obviously safer, but there is a Human Factors issue. Electricians and repair staff in the UK have grown to assume neutral is safe so that increases the chance of an accident if the connection is reversed.
Fortunaaly RCD / RCCD ELCB devices have come along to save us all.

I would change that "neutral is safe" to "neutral is less lethal" in the same sense that a tazer is "less lethal" than a fully fledged firearm. No British sparkie I've ever know is prepared to treat neutral as "safe" unless the supply is locked out, he has the lockout key in his pocket and he's put some kind of test device onto the supposedly locked out circuit. Sparkies get to work near builders, it makes them very cautious.

Now, builders pretending that they know enough to be wiring up mains electricity is a different matter. If they knew enough to actually know what a neutral is they would treat it as safe, but they don't and anyway regard working on live wiring as "safe as long as you're careful". It's because of builders playing electrician (I'm looking at you Roy) that we ended up with "part P" of the building regulations requiring electrical work to be carried out by qualified electricians (strictly speaking by a "competent person").

[xrunner]

After reading the last few posts you guys still think North America (USA/Canada) mains wiring is fucked up?

I think not. 

I'm only going by the American gear that I have seen over here, fitted with a 2 pin plug.

Some items like power bricks still have non-polarized two pins blades (but some are polarized), and some older lamps. The polarized two blade plug has the hot blade smaller than the neutral - only goes in one way. Then the grounded plug of course only goes in one way.

[DC1MC]

You forgot the creme de la creme



https://www.ebay.de/itm/224412798870

[Cerebus]

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.

[capt bullshot]

If on the other hand as others have indicated there no legal requirements for which pin the Hot and Neutral wires are terminated at, then that is a recipe for problems.

Why?

I believe that there must be some standard that electricians have to conform to and that the connections of sockets are clearly defined as to what each is supposed to connected to, so that anything that demands a ground connection for safety can only be connected one way when the plug is plugged in, so that the switch on the equipment and any fuse in the equipment is in the Hot or Live line so that in the even of a problem, the fuse isolates the incoming supply to prevent the metal work on the equipment remaining connected to the Live and still present a dangerous situation.


Here is a European tester

It's not mentioned that often here, but regarding circuit breakers / fuses there are significant differences between UK and mainland Europe.
I've read somewhere that UK uses up to 32A fuses for mains outlet ring circuits.
In Germany (and most other mainland Europe) 10A or 16A class B breakers are used for mains outlet circuits, and these aren't ring circuits, but rather star or bus type.

UK uses sometimes quite thin wires for their power cords, with a 32A fuse in the breaker board, it might happen the cord catches fire before the fuse blows. So placing a correctly sized fuse in the plug is a way to deal with this. As there's only one fuse in the plug, the plug must be polarized, otherwise a Live-to-Earth short still would burn the cord.

Here, there's no power cord using wires of less than 0.75mm². Shorting these wires at the end of a typical power cord (or inside a device) provides high enough short circuit current to trip the 16A B breaker, no matter if the short is L-to-N or L-to-PE. So no need for a fuse inside the plug, and no need for polarized plugs.

All the other stuff (ground fault interuptors etc.) was invented later and is for redundancy, as most of typical safety measures rely on redundancy. First level is the insulation. Second level e.g. is the earthed metal casing (or double insulation), a short from L to case will trip the regular breaker. Third level is the GFCI, if the earth wire is broken (which can happen and no one will notice), it'll trip if someone touches the case.


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.

[beanflying]

You cannot assume that mains wiring is complaint and poke your fingers in the Neutral bit anytime  One moron Apprentice/Sparkie/expurt home owner and you are DEAD. All Aussie compliant sockets and plugs are labelled but so many times not followed. 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.

[med6753]

That's really the key. Don't assume any wiring is compliant or else you be dead. 

[bd139]

Yep.

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

[mnementh]

LMAO that’s horrible. That’s got to be at least 50A that fuse 

Fun job of the evening. Not. Trying to build 300Hz RBW filter for my SA. This unfortunately requires me to build a half decent crystal filter which means matching a shit ton of crystals by hand then characterising them further later. Frequency binning in progress 

Aren't those crystals already marked with their frequencies then? All of mine are, although I have checked them, but they were all correctly marked already?

Yep. 4.9152 MHz with 30pF loading.

That’s fine for oscillators but not for filters! The motional parameters of the crystals are all slightly different so they can vary in the same fixture by up to 100Hz or so. To get a fairly ripple free narrow filter I need really tight matching between them. Ideally I need to find 8 within 5Hz or so with close Lm and Cm.

This is unfortunately why I’ve got a bag of 200 to go through to select some by hand.

This is also why crystals are a few pence each but crystal filters are £100+ 

Awww... who do you think you're kidding, bd? We can hear you grinning like a fool all the way over here.  You like this shit almost as much as winding toroids... 

mnem
 

Well I fell asleep half way through and nearly fell of my chair. It sucks 

So... you were having so much fun sorting your collection of crystals that you stayed up til you passed out from exhaustion at o'dark-thirty in the AM...?

Sounds like nerdly Nirvana to me... 

mnem

[Cerebus]

UK uses sometimes quite thin wires for their power cords, with a 32A fuse in the breaker board, it might happen the cord catches fire before the fuse blows. So placing a correctly sized fuse in the plug is a way to deal with this. As there's only one fuse in the plug, the plug must be polarized, otherwise a Live-to-Earth short still would burn the cord.

You won't find a mains cord of less than 0.75mm² and that's rare except for double insulated items on C7 connectors. Anything on a C13 will have 1.5mm² conductors or larger.

Here, there's no power cord using wires of less than 0.75mm². Shorting these wires at the end of a typical power cord (or inside a device) provides high enough short circuit current to trip the 16A B breaker, no matter if the short is L-to-N or L-to-PE. So no need for a fuse inside the plug, and no need for polarized plugs.

All the other stuff (ground fault interuptors etc.) was invented later and is for redundancy, as most of typical safety measures rely on redundancy. First level is the insulation. Second level e.g. is the earthed metal casing (or double insulation), a short from L to case will trip the regular breaker. Third level is the GFCI, if the earth wire is broken (which can happen and no one will notice), it'll trip if someone touches the case.


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.

[mnementh]

I've got a Saunders crystal imedance meter...  https://prc68.com/I/CrystalImpedanceMeters.html
You could make a trip worthwhile 

Tempting. Very tempting! 

Still need to contact you. Sorry for delay - wrangling large IT migration at the moment so not sure what schedule is looking like yet.

   https://xkcd.com/908/

mnem
fuck AWS.

[Robert763]

You cannot assume that mains wiring is complaint and poke your fingers in the Neutral bit anytime  One moron Apprentice/Sparkie/expurt home owner and you are DEAD. All Aussie compliant sockets and plugs are labelled but so many times not followed. 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.

I perhaps didn't word my comment on neutral very well. Perhaps "Some electricians..." and "perceived safety" would have helped.
Neutral is not safe.

I disagree with your comment on 13A fuses. They are not there for shock prevention they are there to protect the cable connected to the plug. Most plugs should have lower rated fuses anyway because they don't have 1.5mm2 cable.
They are part of the ring main system design, not a fix for a problem. A bit of 0.5mm2 flex connected to a plug with a 5A fuse and then to a ring main with a 32A breaker is better protected than the same flex on a radial circuit with a 16A breaker.

[capt bullshot]

UK uses sometimes quite thin wires for their power cords, with a 32A fuse in the breaker board, it might happen the cord catches fire before the fuse blows. So placing a correctly sized fuse in the plug is a way to deal with this. As there's only one fuse in the plug, the plug must be polarized, otherwise a Live-to-Earth short still would burn the cord.

You won't find a mains cord of less than 0.75mm² and that's rare except for double insulated items on C7 connectors. Anything on a C13 will have 1.5mm² conductors or larger.

I guess you're right for recent stuff. Not different from what you'll find here.

Having visited the UK several times, I clearly remember quite thin wires were used on low power household items like desk lamps etc. Admittedly, these items looked rather historical but in my eyes this stuff was quite common - use thin wires and ensure there's an appropriate fuse (of less than 13A) in the plug. Yes, I've been nosy back then and checked the actual fuse values in the plugs Also have seen various mains distribution panels that made me shudder (of course, in old houses you may find shuddery panels here, too).

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.

[xrunner]

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

For electrical wiring or basically in general? 

[capt bullshot]

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