Possible lightning danger with inverter welder

[NicheFab]

[QUOTE=westom;5965681]Telco $multi-million equipment is connected to wires all over town. That CO will suffer about 100 surges with each storm. So why do they not disconnect? It’s not so much about the gap. Protection is about what the gap (and now semiconductor type protectors) connect to.QUOTE]

k, so the post is old. I'll give my 2c anyway.. There is also lightening protection fuses on the cable pair side of a 5ESS frame that protects incoming cable pair before being manually cross connected to the switch itself.

Attachment 1133421

MANY layers of grounding protection in the belly of a Telco network. Electro-optical isolators on SAT and terrestrial RF connections. At this point in the game, a lot of offices are further isolated due to antiquated cable trunks haven been replaced by optical metro mux systems before being converted back to copper just before hitting a neighborhood. If you live in a big city that has fiber deployment, you have an optical home run back to the office.. don't ask me how I know.. just saying..


I believe that the TA 211i's rear switch is a Siemens breaker if I'm not mistaken, but I could be wrong. I still throw the breaker in my breaker box. I'd rather fry a Square D breaker from lowes than the one in my machine.

-Niche

[farmer37]

Dont know why old posts show up but they have good info in them often.The silicon diode started to be used around 1960.It had one major flaw,lightning strikes destroyed it.When lightning storms moved in mid summer the tv shop got busy replacing silicon diodes.Fence chargers got hit often by lightning.By the way lightning strikes happen year round.I had fence chargers in the shop in winter with major lightning damage.Welders left plugged in often get lightning damage.Check out the old posts when the new posts get boring...

[7A749]

Actually, farmer. You commented on this post first, which was two years old at the time.

No matter, it's relevant information. Power surges kill inverter welders. It's a fact. In every one I've repaired with damage from a power surge, the input rectifier was the first thing to go, which is more or less an SCR.

[westom]

There is also lightening protection fuses on the cable pair side of a 5ESS frame that protects incoming cable pair before being manually cross connected to the switch itself.

Fuses disconnect (a millimeters gap) when current is excessive. Fuses disconnect AFTER damage has occurred.

Fuses take tens of milliseconds or seconds to open. Surges are done in microseconds. Nothing that disconnects will protect from destructive surges.

Will that millimeters gap in a fuse stop what three miles of sky could not? Of course not. Protection is provided by what connects surges 'low impedance' to earth. Same applies to any surge protection even inside every home. Protectors without that low impedance (ie less than 10 foot) connection to single point earth ground do not claim to protect from destructive surges. Somehow, those many times more expensive protectors will somehow absorb or block a surge? Only when advertising and hearsay promote them.

A protector is only as effective as its earth ground. That even applies to welders. A welder is damaged once a surge is all but invited inside to go hunting for earth, destructively, via that welder.

BTW, those early 1960 diodes were germanium. Easier to damage than silicon diodes.

[dbstoo]

NicheFab used the term "fuse" when he might have more appropriately said 'carbons and heat coils". The coil acts as a fuse, the carbons are lightning arrestors.


The carbon is just what it sounds like. It's a carbon block connected to ground separated from a metal electrode by a very small gap. The electrodes are connected to the phone wires. In the event of a high voltage on the wires, it arcs across the gap. If the surge lasts more than a split second it melts the solder that holds the electrode and a spring pushes the electrode against the carbon permanently. At the same time, it opens the circuit on the equipment side.

The coil (works as a fuse) is part of the same device. The coil is part of the phone's electrical path. The coil surrounds the electrode mentioned above. If there is a high current situation the coil heats, melts the solder and the electrode grounds out the wire while interrupting the path.

In my 10 years working in the AT&T switchrooms, I replaced thousands of coil/carbons and less than 100 pieces of burned control equipment. In short. It works.

Dan

[Willie B]

Lightning struck a television antenna. It was mounted on a massive chimney. I'd estimate 4x6' 6' tall from the lowest point it came out of the roof. It brought the chimney to below roof line. No two bricks were still stuck together.

A direct strike will do damage. Most of the anecdotes you hear of are not direct strikes. They are shared strikes. Grounding is your best defense, other devices will help in shared situations.

[Oscar]

I hope a lightning bolt strikes the underground wires running to my house and smokes my HTP 221 DV. I have it outside (where it's been since December '13), and it's always plugged in. This way I can have a reason to go shopping for a Dynasty 280DX.

[NicheFab]

Thank you for clarifying that for me Dan. I was getting ready to respond and saw you beat me to it. I have 16yrs in the field with a competing company. I used to visit POP sites and talk with all sorts of AT&T and other inter-lada guys on a day to day basis. Howdy from the other side of the fence!

For what it's worth, there are many layers to a large telco's grounding and power isolation/backup scheme. The coils are only the first line of protection. Most everything in a large Telco's legacy plant is powered by 48v DC and is buffered from the outside world by rectifiers and battery bays the size of most peoples living quarters. Todays modern "mission critical" networks are buffered from the outside world by UPS systems. Granted it is a two fold advantage to use a UPS, as it provides hold-over till the generators kick in, but also delivers a clean, conditioned wave before it even gets to the equipment.

To be honest, it has been a while since I worked in a CO, at least 8 years, and ensuring TDM data gets from A-Z was my primary focus. I never worked in the outside plant. Now just a network monkey who they bury in the belly of the beast to keep things running smoothly. Happy shiny people everywhere!

-Niche

[dbstoo]

Thank you for clarifying that for me Dan. I was getting ready to respond and saw you beat me to it. I have 16yrs in the field with a competing company. I used to visit POP sites and talk with all sorts of AT&T and other inter-lada guys on a day to day basis. Howdy from the other side of the fence!

back. We may have talked. I worked in the Salinas 1A-HiLo (local and toll (long distance) switch for a few years before the 1984 divestiture, then spent another few years working on Northern Telcoom DMS200 switches in the inter-lata group for Pacific Bell. Oddly, I got my training in computer science when we were learning to maintain the processors for the switching equipment. They were made up of discrete components, so we learned the design inside and out.

Great times.

Dan

[Willie B]

Our local telephone company engineers once had us replace the grounding system in one of their C. O.s. The expensive project consisted mostly of rerouting ground cables with sweeping radius bends along with better terminals where these cables bolted to the buss bars. Theory is, like a race car, lightning surges follow a conductor better if the turns are gentle. At lower voltages this isn't as important.

[7A749]

I hope a lightning bolt strikes the underground wires running to my house and smokes my HTP 221 DV. I have it outside (where it's been since December '13), and it's always plugged in. This way I can have a reason to go shopping for a Dynasty 280DX.

I can give you some information on an easy way to replicate an inverter blowing power surge, then you'll be all set!

You can just thank me later

[westom]

Our local telephone company engineers once had us replace the grounding system in one of their C. O.s. The expensive project consisted mostly of rerouting ground cables with sweeping radius bends along with better terminals where these cables bolted to the buss bars.

Turns are not gentle so that electricity flows straighter. But that is what so many believe due to hearsay. Relevant term was repeated: low impedance. A ground wire from a homeowner's electric box, up over the foundation and down to earth, is good enough for code. And insufficient for earthing surges. Wire is too long. Sharp bends further increase impedance. That quarter inch, solid copper ground wire is not separated from other non-grounding wires. Code does not require this. But those who actually make direct lightning strikes irrelevant learn why low impedance (not resistance) is critical.

Coils and carbons do not do surge protection. Coils melt due to something else called a 'follow through' current that occurs long after a surge is done. Carbons have long been replaced by something superior - semiconductors. And still, that protector does not do protection. A protector only connects energy on a low impedance path to what does all protection - single point earth ground.

Some COs suffer damage. Eventually management concedes. Then engineers upgrade the only reason for that damage. Create low impedance (long sweeping turns) connections. Or better, connections without any bends and, of course, no splices. Best for a homeowner is a bare, solid copper quarter inch wire that goes through his foundation and down to earth. Then it does not have excessive impedance (such as two sharp bends over the foundation.

Protection is always about where hundreds of thousands of joules harmlessly dissipate. Any recommendation that ignores where energy dissipates is, at best, suspect. Defined previously was best protection even for every home - 'whole house' protection. That is only 'secondary' protection. No protection layer exists after that layer because every protection layer is defined only by what absorb energy - earth ground.

'Primary' surge protection layer should be inspected by every homeowner. A picture demonstrates what to inspect - where energy harmlessly dissipates in a 'primary' surge protection layer:
http://www.tvtower.com/fpl.html

Anything that would claim to stop a surge (ie melting coils) is not for surges. If the 'primary' protection layer is compromised (as in that picture), then a more destructive 'follow through' current can exist.

Best explanations of surge protection discuss 'low impedance', 'follow through current', equipotential, single point earth ground, and can always say where hundreds of thousands of joules harmlessly dissipate.

Why was a chimney destroyed? Lightning found an electrically conductive path to earth. But the chimney (like Franklin's wooden church steeple) is not a superior electrical connection- will therefore create a higher voltage. 20,000 volts times that higher voltage means high energy that destroys the chimney. Franklin's solution is obvious. Connect lightning on a path that is more conductive. Then 20,000 amps times a near zero voltage is near zero energy. Nothing destroyed. Same concept also applies to effective 'whole house' surge protection for appliances. Then a high current creates a near zero voltage - no appliances or welders damaged.

Protection is always about where energy dissipates.

[Fab54]

I went decades without ever having an issue. Live in a neighborhood with underground wires. Was away last summer when we had massive thunderstorms. Came home to a fried iMac, router, and two access points. Not sure what happened. The computer hurt the most.

Installed this whole house surge protector:
Leviton 51120-1 Panel Protector, 120/240-Volt ($185 amazon) and surge protectors at every outlet that has electronics. The cost was painful but I felt cost effective in the long run. Worst part is you never know how many times these devices save you. Silent protection from surges but not every type of event....

[Sandy]

Don't be getting power protection, lightening protection and surge protection all garbled together and use big broad general statements all at the same time. That's why some posts make no sense sometimes. Leave the mumbo jumbo to the marketeers who claims to have one magic gizmo that protects anything from everything.

BTW DC = resistance, AC = impedance. Otherwise same thing for general conversation but when the details matter the difference matters.

[Willie B]

Don't be getting power protection, lightening protection and surge protection all garbled together and use big broad general statements all at the same time. That's why some posts make no sense sometimes. Leave the mumbo jumbo to the marketeers who claims to have one magic gizmo that protects anything from everything.

BTW DC = resistance, AC = impedance. Otherwise same thing for general conversation but when the details matter the difference matters.

Would you explain the statement. My 45 years of ongoing education, coupled with experience still has gaps. At no time have I heard this concept, enlighten me. Are you referring to inrush current as compared to impedance found in AC coils?

[rick9345]

And if your welding during the day and a storm comes with lighting, should one stop and unplug? Does lighting only affect unattended shops/equipment?

[Bluewelders]

Resistance is the same for a AC current or a DC current, Impedance is a magnetically induced opposition to current flow that is primarily dependent on frequency .
Though at extremes of high or low frequency they will tend to slop over.

[Sandy]

Would you explain the statement. My 45 years of ongoing education, coupled with experience still has gaps. At no time have I heard this concept, enlighten me. Are you referring to inrush current as compared to impedance found in AC coils?

"Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude."

http://en.wikipedia.org/wiki/Electrical_impedance

A low resistance joint (when measured with your simple DC powered VOM) yet may well be a high impedance joint due to other factors. That difference may be negligible at low freq's and increasingly wider difference at high freq's. Lightening (called that because of the light) includes high freq's. In short a sharp corner in a low resistance (measured with your ohm meter) wire can and does at times present an abstacle to linear travel by lightening. Lightening might very well blow out there looking for a shorter/better path to ground. Amy times that blow out does not result in a better path but still happens none the less. On-and-on. Many low resistance low resistance conductors do (or not) present high impedance issues with various AC circuits. A dent in a microwave wave guide is a good example also (think skin effect at high freqs). This type of discussion is huge and never ending is why I seldom get involved. Two guys could easily set down with a cool drink and discuss way more than could be covered with a weeks worth of typing.

[farmer37]

This one is bs.Lightning protection devises do work.A well pump was hit by lightning.the new pump had a surge protector on the power line.A second strike cooked the protector ,the pump was ok,Ive worked on many fence chargers that had the fuses and mov,s destroyed but no damage to the charger circuit.I know that lightning protection works after doing tv repair since 1955.Again your statement is BS and dead wrong.

[farmer37]

You should stop welding and unplug the welder.Lightning can strike the power line miles away and destroy your welder.I have a friend who has been stuck by lightning twice and survived.I know of 3 boys who didnt survive strikes here.I have had some close calls with lightning over the years.Lightning strikes happen year around,no off season.Your shop tools should always be unplugged when you are not in the shop.

[westom]

Lightning protection devises do work.A well pump was hit by lightning.the new pump had a surge protector on the power line.A second strike cooked the protector ,the pump was ok,Ive worked on many fence chargers that had the fuses and mov,s destroyed but no damage to the charger circuit.

Protection is about earth ground. A plug-in protector or 'protector in receptacle' might connect to earth via a <0.2 ohm (resistance) wire. That same wire can also have 120 ohm impedance. What happens when a plug-in or receptacle protector tries to earth the typically destructive type surge? A tiny 100 amp surge would put attached appliances at something less than (100 amps times 120 ohms) 12,000 volts. Impedance (not resistance) is critical when discussing surge protection. Impedance is why effective protectors are connected as short as possible (ie 'less than 10 feet') to earth ground.

Professional citations define properly earthed protection at 99.5% to 99.9%. Yes, those other plug-in protectors also do work. And then we add numbers. It does maybe 0.2% of the protection for maybe ten times more money. And does almost nothing without the other and properly earthed solution.

Second, appliances (ie pumps and welders) contain robust protection. What happens when a destructive surge approaches a protector and attached appliance? A surge too tiny to overwhelm protection inside an appliance (TV, welder, pump) will also destroy a grossly undersized protector. Again, read spec numbers. How many joules does that adjacent protector claim to absorb? Hundreds? Electronics will routinely convert a hundreds joule surge into low voltage, stable, DC voltages to power its semiconductors. Tiny surges that can damage tiny plug-in protectors also do not damage electronics.

Protection is always about where hundreds of thousands of joules harmlessly dissipate. Proven protectors (completely different from plug-in protectors) remain functional even after direct lightning strikes. The informed understand why a failed protector provides ineffective protection. And why proven protectors remains functional after all surges - including direct lightning strikes.

And finally, why is a protector damaged? A hundreds joules protector tries to absorbs too much energy. So a thermal fuse must disconnect protector parts as fast as possible. Leaves a surge still connected to attached appliances. In rare cases, that fuse does not blow fast enough. Then a house fire occurs. Just another reason why a properly earthed 'whole house' solution is so important. Even APC recently announced some of their protectors are so dangerous as to be removed immediately.

Ineffective (and expensive) protectors fail and can threaten human life. Effective protectors (properly earthed) must not fail even with direct lightning strikes and other just as robust surges. Why is impedance so important? A protector is only as effective as its earth ground. That connection to earth is ciritical. But even that concept, well proven over 100 years ago, somehow is difficult.

A protector is only as effective as its earth ground. It is that simple.

[7A749]

[MinnesotaDave]

Hahah! Subtle

[Willie B]

"Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude."

http://en.wikipedia.org/wiki/Electrical_impedance

A low resistance joint (when measured with your simple DC powered VOM) yet may well be a high impedance joint due to other factors. That difference may be negligible at low freq's and increasingly wider difference at high freq's. Lightening (called that because of the light) includes high freq's. In short a sharp corner in a low resistance (measured with your ohm meter) wire can and does at times present an abstacle to linear travel by lightening. Lightening might very well blow out there looking for a shorter/better path to ground. Amy times that blow out does not result in a better path but still happens none the less. On-and-on. Many low resistance low resistance conductors do (or not) present high impedance issues with various AC circuits. A dent in a microwave wave guide is a good example also (think skin effect at high freqs). This type of discussion is huge and never ending is why I seldom get involved. Two guys could easily set down with a cool drink and discuss way more than could be covered with a weeks worth of typing.

I agree. You coming to VT anytime soon?

[Sandy]

I agree. You coming to VT anytime soon?

wished I could, but nope .