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Old TV caused village broadband outages for 18 months

bbc.com

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Re: Old TV caused village broadband outages for 18 months

#291

Post by fomine3 »

bayindirh wrote: post #12
Nextgrid wrote: post #7

Earlier quoted context omitted.

> running fiber to every home is not very wise, even for long term. Why not? Old copper will keep deteriorating and spending money repairing it is a waste. Fiber on the other hand is future-proof for the next ~50 years provided it's kept in good condition as you can increase bandwidth by upgrading equipment at both ends without replacing the actual glass.

> Old copper will keep deteriorating and spending money repairing it is a waste. Because until fiber becomes economical, you can use your existing infrastructure and keep it up for minimal expense. A carefully installed outdoor cable is extremely resilient to elements, even over long term. Then, after a certain point, instead of running two infrastructures, you can piggyback everything to even higher capacity fiber a…

How deploying fiber more becomes economical? I expect the cost won't decrease much unlike semiconductor. So If it won't be more economical, faster replacement is better strategy.

Re: Old TV caused village broadband outages for 18 months

#292

Post by nucleardog »

marcosdumay wrote: post #259
nucleardog wrote: post #240

Earlier quoted context omitted.

> All anyone has to do is screw up wiring an appliance with exposed metal parts, and the whole thing can be live at potentially lethal mains voltage Or for extra fun, the wiring in the house. Lots of people think things like changing a plug are "easy" (they are), but they're also really easy to screw up. Now you don't need some DIY'd appliance. Your Ikea stuff is now potentially deadly. The number of DIY jobs I've ru…

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body That would be illegal where I live, and I think in most of the world too. In fact, on a standard residential outlet here, it would immediately bring the house power down. Either the body is grounded or it's floating. It should never be linked to the neutral.

> on a standard residential outlet here, it would immediately bring the house power down.

How?

Re: Old TV caused village broadband outages for 18 months

#293

Post by nucleardog »

mturmon wrote: post #265
nucleardog wrote: post #240

Earlier quoted context omitted.

> All anyone has to do is screw up wiring an appliance with exposed metal parts, and the whole thing can be live at potentially lethal mains voltage Or for extra fun, the wiring in the house. Lots of people think things like changing a plug are "easy" (they are), but they're also really easy to screw up. Now you don't need some DIY'd appliance. Your Ikea stuff is now potentially deadly. The number of DIY jobs I've ru…

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body... Another commenter pointed this out, but I have to chime in as well: no. Not true. The neutral is NOT bonded to the exterior body of a metal lamp. Not even on old fixtures built in the 1960s. The old fixtures, if they were metal, were often not grounded, i.e. the lamp might not be connected by a 3-prong plug (hot, neutral, ground).…

Fair enough -- my mistake, just assumed this was kosher based off of finding a few cheap appliances with 120v on the body and finding them plugged into reverse-wired receptacles.

Re: Old TV caused village broadband outages for 18 months

#294

Post by nucleardog »

JonathonW wrote: post #269
mturmon wrote: post #265

Earlier quoted context omitted.

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body... Another commenter pointed this out, but I have to chime in as well: no. Not true. The neutral is NOT bonded to the exterior body of a metal lamp. Not even on old fixtures built in the 1960s. The old fixtures, if they were metal, were often not grounded, i.e. the lamp might not be connected by a 3-prong plug (hot, neutral, ground).…

> The thing that does happen when switching the neutral wire on a lamp is that doing so will energize the more-accessible "outer ring" of the Edison female receptacle rather than the less-accessible "center pin". This means that if you change the bulb with the switch on, you'd be more likely to contact the hot "outer ring". Also, in most cases, the switch is only across (the wire that is supposed to be) the hot lead-…

> This leaves a shock hazard exposed even when the switch is off

Yeah, comment kinda got downvoted into oblivion for a slightly off example, but this was kind of my point. There are a lot of appliances that become significantly less safe when you put the power into places it's not supposed to be. And the danger is non-obvious.

Re: Old TV caused village broadband outages for 18 months

#295

Post by marcosdumay »

nucleardog wrote: post #292
marcosdumay wrote: post #259

Earlier quoted context omitted.

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body That would be illegal where I live, and I think in most of the world too. In fact, on a standard residential outlet here, it would immediately bring the house power down. Either the body is grounded or it's floating. It should never be linked to the neutral.

> on a standard residential outlet here, it would immediately bring the house power down. How?

There's a circuit breaker designed specifically for that. In English I think it's called "residual current device".

Re: Old TV caused village broadband outages for 18 months

#296

Post by phone8675309 »

msla wrote: post #274
phone8675309 wrote: post #236

Earlier quoted context omitted.

The only thing to break the duopoly is some third option that requires no additional last mile infrastructure investment - either a common infrastructure that decouples provider from physical wiring or wireless Internet that isn't horrible.

Just because we want a technology to exist doesn't mean it's ever going to. Regulation deals with the here-and-now.

Fixed wireless internet and satellite internet do exist now - there have been barriers to deployment, some of which have been put up by traditional terrestrial ISPs.

There have recently been well funded pushes into satellite internet such as Starlink and Project Kuiper.

Re: Old TV caused village broadband outages for 18 months

#297

Post by mturmon »

nucleardog wrote: post #293
mturmon wrote: post #265

Earlier quoted context omitted.

> But that nice shiny metal lamp you've got? It's got the neutral bonded to the body... Another commenter pointed this out, but I have to chime in as well: no. Not true. The neutral is NOT bonded to the exterior body of a metal lamp. Not even on old fixtures built in the 1960s. The old fixtures, if they were metal, were often not grounded, i.e. the lamp might not be connected by a 3-prong plug (hot, neutral, ground).…

Fair enough -- my mistake, just assumed this was kosher based off of finding a few cheap appliances with 120v on the body and finding them plugged into reverse-wired receptacles.

Don't mean to be pushy, but: Are there really toasters, of any vintage, that can have an energized case due to a reverse-wired receptacle? I'm doubtful, but I don't know.

Re: Old TV caused village broadband outages for 18 months

#298

Post by nucleardog »

mturmon wrote: post #297
nucleardog wrote: post #293

Earlier quoted context omitted.

Fair enough -- my mistake, just assumed this was kosher based off of finding a few cheap appliances with 120v on the body and finding them plugged into reverse-wired receptacles.

Don't mean to be pushy, but: Are there really toasters, of any vintage, that can have an energized case due to a reverse-wired receptacle? I'm doubtful, but I don't know .

In the toaster case I was more referring to the heating elements inside.

Re: Old TV caused village broadband outages for 18 months

#299

Post by nucleardog »

marcosdumay wrote: post #295
nucleardog wrote: post #292

Earlier quoted context omitted.

> on a standard residential outlet here, it would immediately bring the house power down. How?

There's a circuit breaker designed specifically for that. In English I think it's called "residual current device".

In North America those are more commonly called a GFCI (ground fault circuit interrupter).

They wouldn't trip in this case just by plugging a poorly wired appliance in. They detect an imbalance in current flow between the hot and neutral wires. If they detect more current going out than coming back in, they recognize that the current has found another path (which is bad) and trip.

Unless you have a grounded lamp (which is certainly not common here; I've never seen one) there'd be no alternate path until you provided one by being shocked, so there'd be no immediate trip. It would, however, increase safety by tripping once you were being shocked instead of simply allowing you to continue being shocked.

Re: Old TV caused village broadband outages for 18 months

#300

Post by aaronmdjones »

nucleardog wrote: post #299
marcosdumay wrote: post #295

Earlier quoted context omitted.

There's a circuit breaker designed specifically for that. In English I think it's called "residual current device".

In North America those are more commonly called a GFCI (ground fault circuit interrupter). They wouldn't trip in this case just by plugging a poorly wired appliance in. They detect an imbalance in current flow between the hot and neutral wires. If they detect more current going out than coming back in, they recognize that the current has found another path (which is bad) and trip. Unless you have a grounded lamp (whi…

An RCD/GFCI would immediately trip if anything past it is bridging ground and neutral. As well as ground to line, or line to neutral of another circuit (on a different RCD), or line to line of another circuit (on a different RCD, in single-phase or multi-phase installations), or neutral to neutral on a different circuit (on different RCDs), etc etc.

For example, if someone did indeed have a metal-cased grounded desk lamp whose body was also connected to neutral too; it would trip as soon as you plug it in, whether you turn it on or not, and you won't be able to turn the RCD back on until you unplug the lamp [1].

In the US they're called GFCIs as you point out, but this name is bad, since it implies that it only trips on ground faults. In reality they trip on /any/ current imbalance, regardless of how it's happening, over which conductors, or in which direction it is occurring (after all, we are talking about /alternating/ current here). Among other things, this means that if you take a line conductor from a non-RCD-protected circuit, and borrow the neutral from an RCD-protected circuit to power a load, that RCD will still trip, even though the fault isn't on the circuit(s) that the RCD was installed to protect.

As to tripping should the neutral-connected case develop line potential, a circuit breaker will immediately ([1] Sometimes, depending on design, one can manually hold the tripping latch up to prevent it from disconnecting even when it detects a fault. This is extremely bad design in my opinion, and is not the case with UK RCDs; the tripping mechanism is entirely internal, and even if you epoxy or padlock the latch in the on position, it will still trip correctly. I've seen some circuit breaker designs that suffer this flaw too, but again not in the UK.

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