Why CAT ratings are so important AND safe practises

[HoracioDos]

I agree that CAT ratings are a guidance and education is a key. Customers (skilled and unskilled) should be more aware of it, like fat, sugar or calories in the food. Many things have changed since people is concerned about nutrition facts.

We should ask manufacturers to stop lying about CAT ratings if we know for sure that their products are not in compliance.

[Cerebus]

Maybe we should go back living in caves again 

I thought that some of you antipodeans did! 

[b_force]

We should ask manufacturers to stop lying about CAT ratings if we know for sure that their products are not in compliance.

Than you also should stop asking the costumers to go for the lowest price and/or step away from the whole idea of making as much profit as possible.

I guess the only thing you can do, is form some laws and regulations about it, but there are so many grey areas.
Plus you don't want to much resistance in innovation.
In the end it's a compromise, companies/countries need more 'technical skilled' people because the amount of work.
So somehow they need to make a compromise between how difficult it is to get these skills and to fill all the vacancies.

[b_force]

Maybe we should go back living in caves again 

I thought that some of you antipodeans did! 

Well, according to the pictures they still use electricity, so.. alas.

[Fungus]

But like other people already mentioned, a normal 'hobbyist' will never ever enter those high CAT rated situations.
Why? Because you're simple not allowed to enter these areas without permission (actively checked, or passively secured) 

 

I've got a CAT III area inside my house. CAT IV if I snip a little wire that has a lump of lead squished onto it for 'safety' (as if that little wire would stop anybody, LOL!)

[HoracioDos]

I understand your point but I look the whole thing in a different way.

Than you also should stop asking the costumers to go for the lowest price and/or step away from the whole idea of making as much profit as possible.

I think that's not the problem. Best decisions are usually made when we are well informed

I guess the only thing you can do, is form some laws and regulations about it, but there are so many grey areas.

I don't trust governments for anything good, I don't like to feed bureaucracy monster. I guess that civil organizations could make their own statement to alert customers to avoid some products. It seems that mislabelled DMMs is not an issue for them.

Plus you don't want to much resistance in innovation.
In the end it's a compromise, companies/countries need more 'technical skilled' people because the amount of work.
So somehow they need to make a compromise between how difficult it is to get these skills and to fill all the vacancies.

If any company can't find good engineer to design a multimeter, they are in the wrong business in any market. It's a bad policy in long term for any company or country to allow these product get exported with wrong CAT ratings.

[oldway]

If I understand correctly, the electrician tried to make a measurement with a multimeter on a high energy circuit of 2300V.
It could only end badly.

Which would have only caused damage to the multimeter in the case of a low-energy circuit, becomes a fatal accident with a high-energy circuit.

This is not just a CAT problem.
In the video, we have very well made a list of all the errors and breaches of the safety rules.which have been committed and there are many!
An accident rarely has a single cause ... it is proved once again !.

[mtdoc]

There are good electricians, and there are dead electricians.

This statement and this whole discussion reminds me a lot of similar discussions that take place in the climbing community.

A common saying is "There are old climbers and there are bold climbers but there are no old, bold climbers".

The issue in both settings are the same:  Safety rules are important but they are not alone sufficient.  There are many instances in climbing where blindly following the safety rules can give one a false sense of security and in some cases actually put you in mortal danger.  I believe the same thing is true if working in high power electrical environments.

Understanding the underlying principles, situational awareness and exercising good judgement are the most important thing.

[b_force]

I understand your point but I look the whole thing in a different way.

Than you also should stop asking the costumers to go for the lowest price and/or step away from the whole idea of making as much profit as possible.

I think that's not the problem. Best decisions are usually made when we are well informed

I guess the only thing you can do, is form some laws and regulations about it, but there are so many grey areas.

I don't trust governments for anything good, I don't like to feed bureaucracy monster. I guess that civil organizations could make their own statement to alert customers to avoid some products. It seems that mislabelled DMMs is not an issue for them.

Plus you don't want to much resistance in innovation.
In the end it's a compromise, companies/countries need more 'technical skilled' people because the amount of work.
So somehow they need to make a compromise between how difficult it is to get these skills and to fill all the vacancies.

If any company can't find good engineer to design a multimeter, they are in the wrong business in any market. It's a bad policy in long term for any company or country to allow these product get exported with wrong CAT ratings.

To be clear, I m not saying that I agree with all these things either.
I am just trying to give a general explanation, why and how things work.

Also, I wasn't talking about one company that isn't able to find workers.
I was explaining when a lot of companies have a shortage in workers, that's becoming a national or even an international problem.
Of course it's not in their policy that's allowed to make bad products.
But rather a result of a compromise they made.

Anyway, the point is that these work much more complex and are very far from black & white.

[RGB255_0_0]

If I understand correctly, the electrician tried to make a measurement with a multimeter on a high energy circuit of 2300V.
It could only end badly.

Which would have only caused damage to the multimeter in the case of a low-energy circuit, becomes a fatal accident with a high-energy circuit.

This is not just a CAT problem.
In the video, we have very well made a list of all the errors and breaches of the safety rules.which have been committed and there are many!
An accident rarely has a single cause ... it is proved once again !.

And then you see his colleague walking around with a metal chain down by his trousers.

[HoracioDos]

A common saying is "There are old climbers and there are bold climbers but there are no old, bold climbers".

Paul Petzoldt

[Lightages]

WTF is that rambling stream of conscious rambling. What are you trying to say?

To quote Uncle Martin "You are a very redundant young man, young man!"

Yeah, I goofed up on some wording.  Thank you for being such a word nazi.

[Z80]

You have to wonder why the cheapo companies bother with the fake markings, possibly because they are just copying the big brands and want them to look the same.  I would hate to think that they are driven to do this by the consumer market wanting them as some sign of 'status' or thinking they are better, like the fake mAH ratings on battery banks or the ridiculous wattages on cheap 'hifi'.  The fact remains that the consumer / hobby market doesn't need them, that's why your toaster / TV / fridge doesn't have them.

[Fungus]

You have to wonder why the cheapo companies bother with the fake markings.  I would hate to think that they are driven to do this by the consumer market wanting them as some sign of 'status' or thinking they are better, like the fake mAH ratings on battery banks or the ridiculous wattages on cheap 'hifi'.

What other reason could there possibly be?

[b_force]

It's pretty simple. Because there is a market for and people are willing to pay some money for it.
Their development costs are close to zero.

And ones again, there are A LOT of people who don't know anything about CAT ratings.
In fact, most professional electronics engineers I speak don't know much about it.
It's only electricians who need to know something about it because they have to deal with it on a daily basis.
So they simply see a label, and think it's a proper product.
That's how marketing works.

Maybe this is obvious for you (and us) that these meters are very doubtful in quality.
Keep in mind that in some countries there are no strict rules and regulations.
So from that point of view you can't blame the manufacturer, simply because he probably doesn't know any better.
All his friends, family etc are also exporting cheap stuff, so why can't he do it?
Keep in mind that Chinese business culture is a little different.

From an engineering and cost price perspective I find it very interesting.
Joe Smith showed it's not THAT hard to make a very good performing front end.
So in a sense it would be possible to make a very good performing multimeter for just 25-30 bucks.

[Fungus]

Joe Smith showed it's not THAT hard to make a very good performing front end.
So in a sense it would be possible to make a very good performing multimeter for just 25-30 bucks.

Joe never tests any meter on the current ranges.

You'd need properly rated fuses for the current ranges and that could add $15 to the meter all by itself.

(although I'm still not sure why those fuses cost so much)

[b_force]

(although I'm still not sure why those fuses all the other things cost so much)

That's also part of your answer.
Just because companies can.

[Cerebus]

(although I'm still not sure why those fuses all the other things cost so much)

That's also part of your answer.
Just because companies can.

It's also a question of demand. There are two companies (Bussman, Littelfuse) making fuses that fit the majority of the Fluke handhelds. The 11A fuse has a 20kA interrupting rating at 1000V DC and the 440mA a 10kA rating at 1000V DC, that's quite a tall order for a physically small fuse.

By comparison, the household BS1362 13A fuse has an interrupting rating of 6 kA at 250V AC. These are made by every man and his dog and only cost around the £0.13 mark if bought from Bussman.

A similar rated 20x5mm F 12.5A 250V HRC fuse comes in at around £1.50 for a very similar capability to the aforementioned BS1362 13A.

So, the price factor for 'specialized' 20x5mm versus 'every household' BS1362 is about 11 ¹/₂.

It's plainly obvious that the material costs of a fuse are going to go hand in hand with the power it's rated to break, so the 440mA 'Fluke' fuse should cost around 6.7 times what the 20 x 5mm fuse does. And indeed, £1.50 is something close to the price of a 'Fluke' fuse divided by that 6.7 factor.

So there's two factors.

• Middling demand fuses, such as multimeter fuses and high current 20x5mm HRC are always going to cost more than high demand items like BS1362 fuses which in fact are a bargain for their rated breaking capacity.
• Interrupting capacities of 10kA and 20 kA at 1000V DC are just going to be expensive to implement.

[Fungus]

• Interrupting capacities of 10kA and 20 kA at 1000V DC are just going to be expensive to implement.

It's mostly (all?) just a case of making them bigger. There's no fancy materials inside them, just sand+wire.

It's been suggested that the problem is very tight tolerances in the timing of the way they blow but I find that hard to believe. We consume high-precision parts in every area of our lives for cents apiece. eg. The opening mechanism on soda cans.

My only conclusion is they're overpriced just to reassure us that they're good.

That doesn't explain why the Chinese don't make them for only double/triple the price of BS1362 fuses though.

[b_force]

Be aware that quality isn't proportional to price.
I know some audio companies who sell the same boards for OEM and consumers.
Only the consumer prices are 6 timers higher.
The BOM is almost identical.

I have also seen other companies where I know the exact BOM (and therefore the production price).
They sell their stuff for a much much higher rate.
It's worse with companies that almost have a monopoly.

[Cerebus]

• Interrupting capacities of 10kA and 20 kA at 1000V DC are just going to be expensive to implement.

It's mostly (all?) just a case of making them bigger. There's no fancy materials inside them, just sand+wire.

The external construction of the 'Fluke' fuses is quite different to normal industrial HRC fuses of the same physical size (some sort of glass/kevlar reinforced plastic versus ceramics), and their breaking capacity per unit volume is a bit higher than standard industrial fuses. They have to be made more physically robust because they are expected to blow in hand held equipment, not behind the steel door of some switchgear. I wouldn't however expect this to contribute too much to the cost (cost as opposed to price), maybe a factor of two at most.

But that's not the point, the point is the demand for them and the number of manufacturers versus more everyday fuses. It's economics, not technology.

[Cerebus]

Be aware that quality isn't proportional to price.
I know some audio companies who sell the same boards for OEM and consumers.
Only the consumer prices are 6 timers higher.
The BOM is almost identical.

I have also seen other companies where I know the exact BOM (and therefore the production price).
They sell their stuff for a much much higher rate.
It's worse with companies that almost have a monopoly.

It's got nothing to do with quality (beyond basic product requirements), it's quantity - a market of 10s of thousands versus markets of millions and two manufacturers versus dozens.. An economist would discuss it in terms like 'economies of scale', 'price sensitivity of demand', 'duopoly', 'market entry costs' and 'effective competition'.

[madires]

You can get HRC fuses for DMMs also from ESKA and SIBA for a reasonable price.

[b_force]

Be aware that quality isn't proportional to price.
I know some audio companies who sell the same boards for OEM and consumers.
Only the consumer prices are 6 timers higher.
The BOM is almost identical.

I have also seen other companies where I know the exact BOM (and therefore the production price).
They sell their stuff for a much much higher rate.
It's worse with companies that almost have a monopoly.

It's got nothing to do with quality (beyond basic product requirements), it's quantity - a market of 10s of thousands versus markets of millions and two manufacturers versus dozens.. An economist would discuss it in terms like 'economies of scale', 'price sensitivity of demand', 'duopoly', 'market entry costs' and 'effective competition'.

I can guarantee it's also not always quantity.
Some manufactures just really ask bizarre prices.

[Fungus]

it's quantity - a market of 10s of thousands versus markets of millions and two manufacturers versus dozens.. An economist would discuss it in terms like 'economies of scale', 'price sensitivity of demand', 'duopoly', 'market entry costs' and 'effective competition'.

Nah. If they were cheaper then you'd see them in a lot more meters.