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  #1  
03-10-2022, 05:38 AM
vikinagy97 vikinagy97 is offline
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Hello Everyone,

I have a JVC hr-s9850eu VCR. Because it has a TBC (which is a very sensitive circuit), does it need an UPS and/or a surge protector? The wiring in the house is 30 years old and made from aluminium. If I use this VCR on this wiring, without UPS/Surge protector, will it be bad for the VCR, or for its TBC?

Can lordsmurf answer this for me?
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  #2  
03-10-2022, 11:46 AM
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Not really.

Aluminium wiring isn't used here generally, but provided it's rated correctly it is no more or less problematic than copper, it just needs to have a greater cross section.

Non-speciifc UPSs spew broadband RF by their nature, they're not a panacea. Surge protection might be useful, UPS use the same surge protection topology as a reasonable surge strip or similar, plus most devices are now SMPS so reasonably transient imune by nature.

There's nothing inherently sensitive about this equipment, and you'll need specialist solutions if you're troubled with non-trivial surge events.

If you ultimately think a UPS may be useful you want to arrange your equipment so it's as far away from the devices it serves as practicable.

There's a lot of misunderstanding around about this subject.

Have you had any events in the past where equipment has been damaged?
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  #3  
03-10-2022, 12:07 PM
vikinagy97 vikinagy97 is offline
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"Have you had any events in the past where equipment has been damaged?"

No (at least not because of surges). We unplug our devices in the event of a storm. But a surge is possible even when not in a storm.
Our Al wiring is quite old. I do not know if the Earth wire can effectively protect the JVC VCR from a surge, so I haven't plugged it in since June when I bought it. I use other, non-professional VCRs.
In the near future the wiring will be renovated. Do we need a surge protector which protects the whole house?
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  #4  
03-10-2022, 12:18 PM
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Quote:
Originally Posted by vikinagy97 View Post
"Have you had any events in the past where equipment has been damaged?"

No (at least not because of surges). We unplug our devices in the event of a storm. But a surge is possible even when not in a storm.
Our Al wiring is quite old. I do not know if the Earth wire can effectively protect the JVC VCR from a surge, so I haven't plugged it in since June when I bought it. I use other, non-professional VCRs.
In the near future the wiring will be renovated. Do we need a surge protector which protects the whole house?
No, earthing doesn't play an active role in surge protection, there's sort of an argument it could play a part in gross surge protection, but we'll end up wandering in to different concepts.

For the purposes of this conversation, no. Earthing in essence provides a low impedance path for fault currents, in turn this causes a very high (kA) current to flow, in turn blowing fuses - or-MCBs. Fill in your own local terminology.

I don't know where you are in the world but 30 years isn't desperately aged here.
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  #5  
03-10-2022, 12:26 PM
vikinagy97 vikinagy97 is offline
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But until now I knew that a surge protector does not protect if it's plugged in an unearthed outlet (or an earthed but old outlet). I live in Hungary. I have also read that 30 years is old for Aluminium because it is weaker than Copper.
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  #6  
03-10-2022, 12:36 PM
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Ah, this is why we have to be careful with localisation. You could well be right about aluminium wiring, I'm not used it professionally and being a Brit I assume everything is over-rated copper and assume everything is an earthed socket as that's the only type found here. We don't have any* unearthed sockets in installations.

Reminds me of the Hank Hill catchphrase from King of the Hill, 'grounded outlets' being a source of mirth.

A VCR circuit isn't any more or less sensitive than anything else, JVC units generally use a more basic power supply that Panasonic/Sonys but that's not really a difference for this discussion.

Surge protection 'may' (and most likely does) require warning for protection. A choke & mov/crowbar arrangement being the most likely.

I can't speak as to Hungarian wiring in a professional capacity however.

There's nothing that makes video equipment super sensitive though.

*Bathroom shaver sockets.

-- merged --

^ The above should read 'earthing' not 'warning' apologies!
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  #7  
03-11-2022, 12:55 PM
vikinagy97 vikinagy97 is offline
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If the TBC in a VCR goes out of order, can it be repaired/replaced?
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03-11-2022, 04:34 PM
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Quote:
Originally Posted by vikinagy97 View Post
If the TBC in a VCR goes out of order, can it be repaired/replaced?
Potentially.

Of course it "can" be be repaired if you want to be really reductionist about the subject, but practically it's a 'maybe'. Passive component failure is normally relatively trivial to diagnose and repair - if you have moderate electronics skills.

If you're asking because you think that standard house wiring is going to render your device ruined if you plug it in; you're being overcautious.

As I've said a few times, there's nothing inherently sensitive about this equipment, it's just standard domestic electronics. There are no components inside a video machine or TBC that makes them particularly sensitive to normal power-related issues.

The style of power-supply that these devices use makes them fairly transient immune by nature. Don't get terribly hung up about this.

Video machines aren't any more sensitive than a laptop, PC, television or any other relatively modern electronic device.
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  #9  
03-11-2022, 08:06 PM
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Quote:
Originally Posted by vikinagy97 View Post
I have a JVC hr-s9850eu VCR. Because it has a TBC (which is a very sensitive circuit), does it need an UPS and/or a surge protector? The wiring in the house is 30 years old and made from aluminium. If I use this VCR on this wiring, without UPS/Surge protector, will it be bad for the VCR, or for its TBC?
Can lordsmurf answer this for me?
The TBC inside the VCR isn't anywhere near as sensitive as an external frame TBC. The reason is simple. Consumer items have fuse protections. Sure, the power issue can still plow right through the fuse, and still damage it, hence why you still put expensive electronics on UPS (battery backup surge protection, often with some power cleaning/conditioning). The VCRs are prosumer, pro+consumer insides, and the power boards are consumer.

Honestly, it's the quality of the wiring, more than the materials. You can have a new home with to-code crap wiring, and run into constant issues. Been there, done that. Or an older home, wiring not to modern code, and yet seems to be rock solid power with zero issues. Either way, use UPS.

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Originally Posted by RobustReviews View Post
Non-speciifc UPSs spew broadband RF by their nature, they're not a panacea. Surge protection might be useful, UPS use the same surge protection topology as a reasonable surge strip or similar, plus most devices are now SMPS so reasonably transient imune by nature.
Unfortunately, none of that seems to be true. Rarely FM noise issues on the AV, unless crappy off-brand UPS. The equipment is sensitive, I can only guess you've not lost enough gear over the decades, assuming you've ever been doing this for that long. It hurt when the gear was $300-500, and really hurts now that most of it is $1k+.

Quote:
non-trivial surge events.
No such thing exists, not to electronics. Even a "small" overage/underage can zap gear, ruin it irreparable. Again, I can only guess you've never lost gear. It sucks. The UPS is a cheap insurance policy compared to losing expensive (and now hard to find) gear.

Quote:
If you ultimately think a UPS may be useful you want to arrange your equipment so it's as far away from the devices it serves as practicable.
UPS on floor, gear on desk. Far enough.

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Originally Posted by vikinagy97 View Post
Do we need a surge protector which protects the whole house?
These are awesome, and many rely on natural gas as the backup power source. Not available here.

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Originally Posted by vikinagy97 View Post
But until now I knew that a surge protector does not protect if it's plugged in an unearthed outlet (or an earthed but old outlet). I live in Hungary. I have also read that 30 years is old for Aluminium because it is weaker than Copper.
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Originally Posted by RobustReviews View Post
Reminds me of the Hank Hill catchphrase from King of the Hill, 'grounded outlets' being a source of mirth.
Episode? I need to re-watch this series.

Aside, trivia: As a Brit, you probably have no idea how much of that show is accurate. The creator, Mike Judge, lived here long enough. Part of Beavis & Butthead is the same, and you can especially see 80s/90s accuracy to the goings on in DFW. For example, Joe Adler commercials (Jim Adler). Pancho's restaurant. Kung-Fu on ch39. Many things in both shows. None of that stuff has been true in decades, only then, in that exact place.

Quote:
Originally Posted by vikinagy97 View Post
If the TBC in a VCR goes out of order, can it be repaired/replaced?
No.

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  #10  
03-13-2022, 09:21 AM
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Originally Posted by lordsmurf View Post
The TBC inside the VCR isn't anywhere near as sensitive as an external frame TBC. The reason is simple. Consumer items have fuse protections. Sure, the power issue can still plow right through the fuse, and still damage it, hence why you still put expensive electronics on UPS (battery backup surge protection, often with some power cleaning/conditioning). The VCRs are prosumer, pro+consumer insides, and the power boards are consumer.

Honestly, it's the quality of the wiring, more than the materials. You can have a new home with to-code crap wiring, and run into constant issues. Been there, done that. Or an older home, wiring not to modern code, and yet seems to be rock solid power with zero issues. Either way, use UPS.

Unfortunately, none of that seems to be true. Rarely FM noise issues on the AV, unless crappy off-brand UPS. The equipment is sensitive, I can only guess you've not lost enough gear over the decades, assuming you've ever been doing this for that long. It hurt when the gear was $300-500, and really hurts now that most of it is $1k+.

No such thing exists, not to electronics. Even a "small" overage/underage can zap gear, ruin it irreparable. Again, I can only guess you've never lost gear. It sucks. The UPS is a cheap insurance policy compared to losing expensive (and now hard to find) gear.

UPS on floor, gear on desk. Far enough.

These are awesome, and many rely on natural gas as the backup power source. Not available here.

Episode? I need to re-watch this series.

Aside, trivia: As a Brit, you probably have no idea how much of that show is accurate. The creator, Mike Judge, lived here long enough. Part of Beavis & Butthead is the same, and you can especially see 80s/90s accuracy to the goings on in DFW. For example, Joe Adler commercials (Jim Adler). Pancho's restaurant. Kung-Fu on ch39. Many things in both shows. None of that stuff has been true in decades, only then, in that exact place.

No.
This is quite toe-curling.

If I acted as an authority on a subject and then trotted out statements like some of these, I would probably hope somebody would interject.

I'm going to here.

I am academically qualified in this field, with decades of experience in the design and application of system-critical small-signal electronics, I am also a qualified electrician - you are, to my knowledge neither of those things. I'm a middling guy in my field, I've worked with many who have forgotten more than I'll ever know and I worked on highly application-specific units (scientific instrumentation, mostly pharmaceutical & public utility compositions) but I hope you appreciate that does mean I'm probably affaitwith video machine circuits, noise and power supplies.

I'm a bit out of date and beyond doing updates I've not worked as an electrician for a good few years, just in full declaration.

Learn some AC and DC power theory, fundamentals of power-conditioning, power-supply topologies and their applications and basic electrical safety requirements, then you can come back to me with legitimate concerns.

You do not appear to have a fundamental understanding of this subject. Your posts on these matters are full of misappropriated terms that make you look quite silly to those who actually know this subject, or non-sensical or illogical conclusions told with an air of authority. That's quite a toxic combination.

You're intensely knowledgeable on so many subjects and hordes look to you as an authority on many topics with wholly legitimate justification. You do a disservice to the community sometimes when you approach some of these subjects as you will post terms you don't seem to fully comprehend, misidentify components or make explanations that are not on the same plane of reality the rest of us who work with electronics understand.

You've not got to go to undergraduate level, but please, my suggestion would be to pick out a few fundamental electronics textbooks or web sources and work through a few critical chapters before brow-beating those who are very conversant in these topics are trying to offer legitimate advice. I'm far from the first person you have done this to.

This post won't make me popular, but I've tried gently to disabuse you of a few major errors in your understanding of these topics. Now I'm trying to be a touch more upfront.

I hope we don't fall out, and I reiterate you are an oracle on many matters in this field and rightly looked to by potentially thousands of individuals, but you're weak in fundamental knowledge here and speak with authority.

There are matters of opinion, and there are physical laws that govern the universe. Only one heading there is up for debate, I think without realising it, you often pick up arguments in the latter without realising.

It's always okay to ask questions, there are many on here who'd be more willing to help you and others on these matters, but you've got to stop arguing with people who may know a thing or two more than you about these topics first. Drop me a PM if you want any explanations, I'm always willing to help where I can.

I hope this is taken in the spirit is intended.
RR

-- merged --

To pick up the question about distributed over-voltage protection in an installation ('whole house') - then I assume you're talking about something like one of these? This is provided as an example, not a recommendation. Check your own local regulations, installation type, part availability etc.

Yes, they're fantastic and they're going to no doubt become mandatory in new installations here soon (as per spark arrest) and they're a nice noise-free solution. They can be discriminated in a circuit too, so you could specify a multi-layered approach but that's probably overkill for a home.

For clarity, they don't require any sort of fuel

Installation should be carried out by an appropriately skilled individual though as there's going to be an assurance of earth that matches specification (otherwise you'll be dumping the transient energy to erm... nothing.. that will get messy...), also installation will require adequate isolation etc. Great idea and relatively cheap (we use them in our offices) - install and forget. They may require replacement after a catastrophic event, but there's no such thing as a free lunch here, dump 40kA through anything that size and it'll get a 'spanking'...

They offer a far greater degree of surge protection than a cheap APC UPS or similar, they need no maintenance or routine replacement and they're 'always on' and protect the whole installation, cheaper too if it's feasible to install one.

Check what's available and specified in your market.
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  #11  
03-13-2022, 11:32 AM
dpalomaki dpalomaki is offline
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The problems with Al wiring were mainly due to corrosion at connections and poor initial installation practices that, at least in the USA, tended to cause issues leading ultimately to fires when connections started to fail. This was especially common with smaller branch circuits (e.g., 15, 20, and 30 amp). It did not happen to ever house or a high percentage of houses, but did to enough to cause insurance companies and people to worry. (I lived in a house with Al branch circuit wiring from 1979 to 1984 without issues, as of this year the house is still standing.) Al wiring is still used for large wire sizes such service entrances. (Al wiring was used in the 1970s for branch circuits because copper became very expensive for a while.)

What you need in surge protection will depend on the quality of your power source, and that includes factors such as prevalence of electrical storms, frequency of outages, system stability, the nature of other electrical loads sharing your power feeds, and your tolerance for associated risks. Most consumer and prosumer electronic gear works well with low risk of damage for most people on most home electrical systems. Note that I said most and low risk, not all and no risk.

Most power strip type surge protectors will provide some line-to-line (or phase-to-neutral) overvoltage protection. If there is a good ground wire in the circuit (required in the USA for number of years now) they can also provide some line-to-earth over voltage protection.

UPS, surge protectors, power conditioners come in many varieties with widely different capabilities. What to use depends on your specific circumstances, not the least is available funds. I manage much of my risk by avoiding PC use during storms and if outages are expected.
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  #12  
03-13-2022, 11:42 AM
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The problems with Al wiring were mainly due to corrosion at connections and poor initial installation practices that, at least in the USA, tended to cause issues leading ultimately to fires when connections started to fail. This was especially common with smaller branch circuits (e.g., 15, 20, and 30 amp). It did not happen to ever house or a high percentage of houses, but did to enough to cause insurance companies and people to worry. (I lived in a house with Al branch circuit wiring from 1979 to 1984 without issues, as of this year the house is still standing.) Al wiring is still used for large wire sizes such service entrances. (Al wiring was used in the 1970s for branch circuits because copper became very expensive for a while.)

What you need in surge protection will depend on the quality of your power source, and that includes factors such as prevalence of electrical storms, frequency of outages, system stability, the nature of other electrical loads sharing your power feeds, and your tolerance for associated risks. Most consumer and prosumer electronic gear works well with low risk of damage for most people on most home electrical systems. Note that I said most and low risk, not all and no risk.

Most power strip type surge protectors will provide some line-to-line (or phase-to-neutral) overvoltage protection. If there is a good ground wire in the circuit (required in the USA for number of years now) they can also provide some line-to-earth over voltage protection.

UPS, surge protectors, power conditioners come in many varieties with widely different capabilities. What to use depends on your specific circumstances, not the least is available funds. I manage much of my risk by avoiding PC use during storms and if outages are expected.
We have a 'rule of thumb' to double cross-sectional area (vs copper) in aluminium here, I think that can be used in place of calculations but it's a while since I looked at it. It's uncommon here in domestic installations but we wire in rings so you're getting into some seriously thick cable runs to make aluminium meet specifications; we're odd like that - our domestic wiring is arse-backwards compared to the rest of the world.

With the US, is there any reasoning in your earthing/grounding of sockets/outlets? I know it just seems a bit haphazard where some sockets just seem to have a ground pin and some don't? I know there are polarised and non-polarised versions of your sockets too? Is there an expectation that in x-environment there are earthed outlets etc?

I've mixed up earth/ground and socket/outlet to keep everybody happy

Edit - you'd need 16mm˛ (6 AWG) x6 in the back of a British standard socket on a ring-final with aluminium.... Yeah.... We feed our sockets with 2x Line 2xNeutral 2x Earth, we have a big loop that covers the whole house.

Last edited by RobustReviews; 03-13-2022 at 11:52 AM.
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  #13  
03-13-2022, 02:05 PM
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This is quite toe-curling.
I am academically qualified
I'm a middling guy in my field,
I'm a bit out of date
You do a disservice to the community
pick out a few fundamental electronics textbooks or web sources a
I've long been a proponent of reading, learning, getting an education. But sometimes scholars can get their noses stuck in books, lose touch with reality. There are times when academic theory simply is not the practical application. That takes a wisdom beyond academia. With certain subjects, I've long called BS. The idea that electronics will be "fine" with unstable power is one of those areas.

When power dips, surges, or even fails -- and without any storms whatsoever -- and you lose gear, expensive gear (fails, cannot be repaired), what then? Will your academic superiority comfort you?

Losing gear = toe curling, gut/crotch punching
Not telling others they can lose gear without UPS = disservice to the community

For whatever reason, you have a bias against UPS. I get that. But I never said a UPS was flawless, a panacea to solve all power issues. But it's a cheap insurance policy to protect against damage, one that often saves gear. That's it. Same for computers.

If you don't want to protect yourself, that's on you. You've been warned. As I stated, I can only guess that you've never lost expensive gear. Others likely will not follow you off that cliff.

As @dpalomaki stated, there are variables to this. I have a feeling your luck and unusual good experiences are blinding you to a larger picture. When you teach others, especially when it comes to dangers, you need a macro view. Sure, you can usually walk across a street without looking both ways. But that will fail for somebody eventually.

What I'm asking you to consider here is what actually happens (not a book), and to consider the power issues that others deal with on a regular basis. Not just your exact UK location, but elsewhere in UK, other countries, both rural and urban. It's not all the same. And when confronted by that scary reality, UPS should be a no-brainer. eBay isn't full for "for parts or repair" gear simply due to owner misuse. Power plays a role there as well, especially with models that have caps issues.

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03-13-2022, 03:01 PM
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Originally Posted by lordsmurf View Post
I've long been a proponent of reading, learning, getting an education. But sometimes scholars can get their noses stuck in books, lose touch with reality. There are times when academic theory simply is not the practical application. That takes a wisdom beyond academia. With certain subjects, I've long called BS. The idea that electronics will be "fine" with unstable power is one of those areas.

When power dips, surges, or even fails -- and without any storms whatsoever -- and you lose gear, expensive gear (fails, cannot be repaired), what then? Will your academic superiority comfort you?

Losing gear = toe curling, gut/crotch punching
Not telling others they can lose gear without UPS = disservice to the community

For whatever reason, you have a bias against UPS. I get that. But I never said a UPS was flawless, a panacea to solve all power issues. But it's a cheap insurance policy to protect against damage, one that often saves gear. That's it. Same for computers.

If you don't want to protect yourself, that's on you. You've been warned. As I stated, I can only guess that you've never lost expensive gear. Others likely will not follow you off that cliff.

As @dpalomaki stated, there are variables to this. I have a feeling your luck and unusual good experiences are blinding you to a larger picture. When you teach others, especially when it comes to dangers, you need a macro view. Sure, you can usually walk across a street without looking both ways. But that will fail for somebody eventually.

What I'm asking you to consider here is what actually happens (not a book), and to consider the power issues that others deal with on a regular basis. Not just your exact UK location, but elsewhere in UK, other countries, both rural and urban. It's not all the same. And when confronted by that scary reality, UPS should be a no-brainer. eBay isn't full for "for parts or repair" gear simply due to owner misuse. Power plays a role there as well, especially with models that have caps issues.
I think you misunderstand, I've got nothing against UPS, I just think they're a questionable strategy in some situations. I've never told anybody not to use one.

You also didn't read my post well enough, we do have power conditioning strategies in my offices (AV, and my other businesses), just UPS doesn't form part of it for AV.

I'm very practical (one does not work for years as a jobbing electrician without some practical skill) so I'll dismiss the idea that I'm solely book-learned. There's without getting into the bulk of my first career, which was very much practical.

You can cherry-pick my comments if you wish, that's your right but I'm confident enough in those statements, I wouldn't have made them. You've clipped off what I said after 'I'm academically qualified' which is quite obvious.

I'm out of date, certainly, I don't buy the literature anymore, I don't get sales engineers knocking at the office door anymore, I don't maintain any professional registration beyond updating my electrical 'tickets' to be able to carry out work in my own homes (it's quite therapeutic to an extent), so yes, compared to the folks doing this daily now I am out of date, that's just statements of fact I'm happy to wear.

Fortunate I have the knowledge and fortunate I don't have to worry about doing it for a living anymore.

Middling in my field, certainly, I worked with guys and gals who worked in my field for decades longer than me, post-grad researchers, old techs', sitting on trade panels with some absolute EE geniuses etc, yes I'm happy to say I'm no master of my trade; very few are. That's a dangerous mode of thought to get into, failing to admit one's limitations, skill set and talents.

I'd rather that than hubris.

Do you think this renders me unqualified? If you do please take that thought away with you.

You have made some rather strange statements about electronic matters though which are patently wrong and rather than accepting that some around you may have more knowledge than you in specific fields, you double down. That's what's curious.

I don't want a protracted debate, I'm confident in what I've said, there are too many examples of some bizarre statements you've made about electrical matters.

It doesn't detract from your other wide knowledge though, not at all, just in this area.
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03-13-2022, 06:03 PM
dpalomaki dpalomaki is offline
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Quote:
With the US, is there any reasoning in your earthing/grounding of sockets/outlets?
Safety. In the USA most residential and desktop appliance power is 120 VAC. Branch circuits are normally 15 or 20 amp rated . High power users, such as window unit A/C over 1-ton, clothes dryers, water heaters, electric ranges, large space heaters, are typically 240 VAC. These days power to a house is typically 240 volt "balanced" with a center tap to give a pair of 120 volt single phase. The center tap is the "neutral" and typically earth grounded at the power panel and no where else in the branch circuits. A separate"green" wire earth ground is also carried in the branch circuits (the circular connector in the typical wall plug). This is for safety and became common only after the 1950s or so. The more modern two-blade plugs are nominally polarized so the wider blade is the neutral. Older extension cords were not thus polarized and not fully compatible with the newer ones because they will not accept the wider blade.

This scheme also facilitates used of ground fault interrupters to detect and isolate weak shorts to ground. The newer type ground fault interrupters can also detect other certain circuit problems like arcing connections that are not ground faults.

As residential electrical loads have grown so have the service practices changes and codes been revises. every few years. 120 volt service became 240/120, 60 amp capacity service became 100, 150, 200 amp and more. Fusing on both legs of a 120 volt branch circuit became a fused 120 volt line and a neutral (if the fuse blows the circuit should be dead, not back fed from the fuse that didn't blow). Nob-and-tube wiring common in the 1930 replaced by Romex, etc.

Again all driven by safety concerns (read insurance companies and law suits).

Quote:
Sure, you can usually walk across a street without looking both ways.
And that depends on where you live too. Some place you can't safely even if you do look both ways.

Regarding UPS, there is no substitute for human stupidity. I worked at a place that had a major date center protected by a sophisticated UPS. But no one in charged bothered to read the maintenance manual. Ir clearly said tr replace the output filtering capacitors every 3 years. At the 4.5 year point the system failed and to took a week to get everything back up. To add insult to injury they had fired only guy who knew how to reboot a legacy accounting system that had run for 3 years without a restart.

.
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03-13-2022, 06:35 PM
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Originally Posted by dpalomaki View Post
Safety. In the USA most residential and desktop appliance power is 120 VAC. Branch circuits are normally 15 or 20 amp rated . High power users, such as window unit A/C over 1-ton, clothes dryers, water heaters, electric ranges, large space heaters, are typically 240 VAC. These days power to a house is typically 240 volt "balanced" with a center tap to give a pair of 120 volt single phase. The center tap is the "neutral" and typically earth grounded at the power panel and no where else in the branch circuits. A separate"green" wire earth ground is also carried in the branch circuits (the circular connector in the typical wall plug). This is for safety and became common only after the 1950s or so. The more modern two-blade plugs are nominally polarized so the wider blade is the neutral. Older extension cords were not thus polarized and not fully compatible with the newer ones because they will not accept the wider blade.

This scheme also facilitates used of ground fault interrupters to detect and isolate weak shorts to ground. The newer type ground fault interrupters can also detect other certain circuit problems like arcing connections that are not ground faults.

As residential electrical loads have grown so have the service practices changes and codes been revises. every few years. 120 volt service became 240/120, 60 amp capacity service became 100, 150, 200 amp and more. Fusing on both legs of a 120 volt branch circuit became a fused 120 volt line and a neutral (if the fuse blows the circuit should be dead, not back fed from the fuse that didn't blow). Nob-and-tube wiring common in the 1930 replaced by Romex, etc.

Again all driven by safety concerns (read insurance companies and law suits).

And that depends on where you live too. Some place you can't safely even if you do look both ways.

Regarding UPS, there is no substitute for human stupidity. I worked at a place that had a major date center protected by a sophisticated UPS. But no one in charged bothered to read the maintenance manual. Ir clearly said tr replace the output filtering capacitors every 3 years. At the 4.5 year point the system failed and to took a week to get everything back up. To add insult to injury they had fired only guy who knew how to reboot a legacy accounting system that had run for 3 years without a restart.

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Ah that's interesting, it's just seemed when I'm in the US it's a right old mixture of types. We just have a standard plug/socket combo.

Are the transformers part of the installation or are they external to the property? I guess they're owned by the distributor? I was aware of the 0V tap but didn't know it was used as the grounding point, or whether there is a separated conductor all the way back to the "ground". It's always useful to have an overview of other systems, always useful knowledge when discussing things.

Fused neutrals are a big no-no here, I've seen the quite catastrophic (fortunately only to equipment) results of heroes running into an assumed dead circuit (fuse has blown innit - it's dead) and finding line voltage in the machine, but with your system, I can see the benefit.

Not UPS, but I did see the aftermath of an impossibly elderly unmaintained PFC unit suddenly "bang" (to say the least) when a rarely used 11kV motor came online at a water treatment plant after years of laying idle... There were divets in the ceiling of the plant room, things went very, very wrong.

Bit off-topic, but it's always useful to know the vagaries of different systems.
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  #17  
03-13-2022, 07:10 PM
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lordsmurf lordsmurf is offline
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Originally Posted by RobustReviews View Post
You can cherry-pick my comments
It's not for anything nefarious, just what I want to address.

Quote:
I don't want a protracted debate, I'm confident in what I've said,
It doesn't detract from your other wide knowledge though, not at all, just in this area.
I don't need a wide knowledge of electricity. I need practical knowledge, as it relates to protecting video gear, and my investment in video gear. That means UPS. The minutia of how/why simply does not matter. I'm not looking for an EE degree, I'm looking for protection.

UPS:
- maintains power
- often has some conditioning, aka AVR/etc, for incoming dirty power

Is UPS perfect? No.
- potential to add noise, though rarer
- really bad surge/spike/etc can ramrod through UPS, kill it and the devices attached
- it can fail at any time, circuit faults happen, usually a worry after 5-6 years of nonstop use
- batteries can fail, and have expected life cycles of about 3 years

But do the negatives means it should not be used? No.

I'm all for theory, academic discussions. But when it comes to practical application, theory that gets in the way must be ignored. Again, when you lose a $2k TBC "but, but, the book/person says ___" will be no consolation.

Our OP here is rightfully nervous about unreliable power. So get a UPS.

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  #18  
03-13-2022, 08:28 PM
dpalomaki dpalomaki is offline
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Quote:
Are the transformers part of the installation or are they external to the property?
Depends. For typical residential privately owned homes one power transformer can serve one or more dwellings and it is typically owned by the power company. The transformer steps down from the distribution voltage, often around 7 to 13KV to 120/240 volts single phase for use in the home. It is typically pole or pad mounted, occasionally in a underground vault with 120/240 volt voltage lines through the meter to the home's service entrance/power panel. For larger complexes such as apartment buildings it is whatever is worked out between the property owner and electric company, and might have transformer in a vault that is part of the building.

There is a wide variety of wiring in the USA due to several factors. Houses and their wiring may date back 100+ years, technology and materials have and continue to change, and codes/standards have changed. Existing installations often are grandfathered, especially residential, until major renovation which may require updates to current codes. In some cases an update maybe driven by the inability to obtain insurance on an otherwise grandfathered installation; e.g., an insurance company might not write a policy on a home with a 60 amp fused electrical panel.

Anything man made can fail; the issue is to understand the risk manage and it down to an acceptable level. A UPS can provide power limited by its reliability, power rating and storage capacity. Capacity declines as batteries age. Reliability declines as components age. Battery life is impacted by operating conditions such as temperatures, discharge rate and depth, float conditions, and cycles.

In the end "We pays our money and takes our chances."
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  #19  
03-23-2022, 05:39 AM
vikinagy97 vikinagy97 is offline
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Which UPS do you recommend?

The wiring will be renovated in the near future. Then I would like to use the JVC VCR to record some TV shows in S-VHS. So, again: which is the best UPS with Surge Protector that you would recommend?

Thank you in advance.
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  #20  
03-23-2022, 07:16 AM
RobustReviews RobustReviews is offline
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Quote:
Originally Posted by vikinagy97 View Post
Which UPS do you recommend?

The wiring will be renovated in the near future. Then I would like to use the JVC VCR to record some TV shows in S-VHS. So, again: which is the best UPS with Surge Protector that you would recommend?

Thank you in advance.
My opinion - basic UPSs make fairly middling surge protectors, they're no better or worse than a reasonable power-strip with surge protection as they're all using the same method. The 'surge protection element is a pretty basic circuit, there's nothing smart about a basic UPS' surge protection. The modest APC units as one example don't have any 'secret sauce' for handling surges.

I'm going to try and explain, I'm painting broad brush strokes here, and there are obfuscations I wholly admit. This is not aimed at SMPS experts, which I do not consider myself for one moment to be, but let's actually look at a schematic rather than just guessing.

We're dealing generally with SMPS' here, and you're in luck, the JVC units have their own effective surge protection built-in by design like most 'modern' designs. I've attached the schematic of the standard JVC SMPS, note the two MOVs, they will shunt the supply instantaneously once they reach their clamping voltage (for this discussion, the maximum voltage permitted).

This is sometimes referred to as the 'crowbar' technique: it's the same as throwing a crowbar between Line & Neutral, under this condition the effectively 0Ω short will cause the device to try and draw 'infinite' current, with a fuse in the way with a rupture current of 1.25A this obviously is not going to survive the ordeal and die a rather spectacular death very, very, very quickly and isolate the device from the supply. Let's replace the fuse and off we go again.

This is exactly the same technique used by modest UPSs.

Now, 'dirty electricity - again, we're dealing with SMPS, this isn't your Grandad's linear PSU, this is a switching power supply, it basically 'doesn't' care' within the bounds of any realistic events - two reasons:

Firstly, note the two-caps and choke immediately on the input, this is neatly rejecting common-mode noise (that's the noise that appears in both the L and N conductors and is the same technique used by SMPS) - basically, any energy that appears in L and N at the same time with be ignored, which is a very effective method of fundamental power-line filtering (it also counters CM-Noise and HF generated by the device. Without getting into reactance, the capacitors are also removing high-frequency components.


Secondly, this is switching methodology, we need to get into DC to do anything useful and you'll notice that immediately after surge and filtering is the rectifier bridge... For the purposes of anything that's likely to happen on a general service power-line it's not fussed at all about the waveform shape it neither knows nor cares about sine-waves.

Also, this is an isolated SMPS, the primary (the mains side) and secondary have no physical connection, beyond a spark event making its way between the primary and secondary side they live in electrically separate worlds. There is no realistic way for the primary voltage to ever find itself appearing on the secondary. Note two separate 0V points on the schematic.

'Undervoltage' is also for all intents and purposes nonsense in this scenario too.

I'm happy to be questioned on this, but please, with reference to the schematic and electrical principles in mind.

----
Now, if you want to go 'belt and braces' and you're having a rewire then if they're available in your market I would suggest a panel type surge-protector for your whole house if you're really concerned, they offer far better protection than a modest UPS and they'll protect everything in your home, set & forget.

If you think a UPS is a proper strategy, stick with a known quantity like APC and keep it as far as practicable from AV devices (a good few metres). UPSs can be absolute hell when it comes to broadband emission, and they're notoriously noisy buggers.

Takeaway points:

- This device deals with surges effectively;
- The 'dirty electricity stuff isn't really relevant here unless it's gross;
- Nothing inhernent about aluminium wiring generates noise or over-voltage conditions;
- SMPS are by design, pretty tolerant to general power-line issues.


Hope that helps, schematic is attached.


.


Attached Files
File Type: pdf JVC PSU.pdf (152.6 KB, 4 downloads)
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