EMP or CME vs Flashlights

aznsx

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Hmmm. I have a problem. My electric ground is on the back of the house, and my fiber optic box is on the front of the house, and when they installed the fiber optic box, the crew drove a ground rod into the ground there, and grounded the fiber optic there in front--not tied to the rest of the house ground. Sounds like this could be a major problem. Yes?
Funny that I used to work at/for fiber network equipment mfgr., but never dealt with and don't know anything about residential FTTH CPE. I was going to ask if you had a link to info or photo of what's installed at your house, but this is probably even easier / better...

What type of physical network connection is it that actually brings the signal(s) into the house from the device they installed at the front of the house; is it fiber of some type, or metallic cable / wire like twisted-pair Ethernet cabling, coax, or the like? That'll tell me what I should be thinking about - assuming I can still think, which can be dicey.
EDIT: P.S. ....and is that device powered from your house?
 
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IMA SOL MAN

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Funny that I used to work at/for fiber network equipment mfgr., but never dealt with and don't know anything about residential FTTH CPE. I was going to ask if you had a link to info or photo of what's installed at your house, but this is probably even easier / better...

What type of physical network connection is it that actually brings the signal(s) into the house from the device they installed at the front of the house; is it fiber of some type, or metallic cable / wire like twisted-pair Ethernet cabling, coax, or the like? That'll tell me what I should be thinking about - assuming I can still think, which can be dicey.
EDIT: P.S. ....and is that device powered from your house?
Two fibers into a terminal box mounted on the house. Only one is connected, the other is for backup purposes in case the other fails. It contains a NiMH backup battery. From the box, a hole is drilled through the wall, and CAT5E Ethernet cable is run through. It connects to the WIFI router, which is plugged into the 110v AC wall outlet. Also, a 110v line from the outside box is run through the hole in the wall and plugs into the wall outlet--that keeps the backup battery charged as I recall. I was not observing when they connected the ground rod, so I don't know how it is connected.
 
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aznsx

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Two fibers into a terminal box mounted on the house. Only one is connected, the other is for backup purposes in case the other fails. It contains a NiMH backup battery. From the box, a hole is drilled through the wall, and CAT5 Ethernet cable is run through. It connects to the WIFI router, which is plugged into the 110v AC wall outlet. Also, a 110v line from the outside box is run through the hole in the wall and plugs into the wall outlet--that keeps the backup battery charged as I recall. I was not observing when they connected the ground rod, so I don't know how it is connected.
I'll cogitate on that when my cogitator's working well. Good description.
 

bigburly912

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Two fibers into a terminal box mounted on the house. Only one is connected, the other is for backup purposes in case the other fails. It contains a NiMH backup battery. From the box, a hole is drilled through the wall, and CAT5E Ethernet cable is run through. It connects to the WIFI router, which is plugged into the 110v AC wall outlet. Also, a 110v line from the outside box is run through the hole in the wall and plugs into the wall outlet--that keeps the backup battery charged as I recall. I was not observing when they connected the ground rod, so I don't know how it is connected.
Is your outlet grounded?
 

jtr1962

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If it isn't a #4 bar (1/4") of solid copper driven minimum 10' (and has 25 ohms or less resistance) it may not withstand a lightning strike. The utility companies usually use a pencil road at 2' or less deep. Eh's that's better than nothing but not much.

Traffic signals, bridges, radio antenna's and such use a series of #4 bars usually driven 30 feet or more to obtain that 25 or less ohm resistance. I've seen them driven as much as 110 feet before getting a good ohm reading.

They use 10 foot sticks and drive it to near ground level. If more is needed the next 10 foot stick is added via weld and driven. Every so often they hit what's called absolute refusal where you time it in minutes vs inches. An inch per minute, keep driving. An inch (or less) per 5 minutes, yeah close enough.
Would underground water mains qualify as a good ground? I've heard of people grounding to their plumbing.

Our house is 1952 vintage. I don't even know where or if there's a real ground. I do know that the outside line connected to the breaker box passes through a ~2" conduit which is a few feet underground. That seems to be the common ground for the entire system. NYC requires BX cable. Whenever I've done wiring, I make sure the jacket of the cable has a screw from the outlet box touching it.

No idea if this entire system is adequate or not.
 

aznsx

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If it isn't a #4 bar (1/4") of solid copper driven minimum 10' (and has 25 ohms or less resistance) it may not withstand a lightning strike. The utility companies usually use a pencil road at 2' or less deep. Eh's that's better than nothing but not much.

Traffic signals, bridges, radio antenna's and such use a series of #4 bars usually driven 30 feet or more to obtain that 25 or less ohm resistance. I've seen them driven as much as 110 feet before getting a good ohm reading.

They use 10 foot sticks and drive it to near ground level. If more is needed the next 10 foot stick is added via weld and driven. Every so often they hit what's called absolute refusal where you time it in minutes vs inches. An inch per minute, keep driving. An inch (or less) per 5 minutes, yeah close enough.
That's interesting. Making a proper connection to the Earth isn't as easy as most might think. I'm not typically involved in making that connection myself, but there's a lot to it, and, that's interesting insight!
 

aznsx

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Would underground water mains qualify as a good ground? I've heard of people grounding to their plumbing.

Our house is 1952 vintage. I don't even know where or if there's a real ground. I do know that the outside line connected to the breaker box passes through a ~2" conduit which is a few feet underground. That seems to be the common ground for the entire system. NYC requires BX cable. Whenever I've done wiring, I make sure the jacket of the cable has a screw from the outlet box touching it.

No idea if this entire system is adequate or not.
I wouldn't know either, but if it's a year older than me and still works, it must be OK;-)

As you likely know, from our usual perspective, while ground quality is an issue, multipoint grounding with ground loops between them is usually when things really go sideways.
 

jtr1962

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As you likely know, from our usual perspective, while ground quality is an issue, multipoint grounding with ground loops between them is usually when things really go sideways.
Yep. Same principle applies to laying out circuit boards. Ultimately you want all the grounds in the individual portions of the circuit to directly connect to a single ground point, which in turn goes to the negative terminal of the battery or power supply. When you don't do this, strange things can happen.
 

aznsx

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Yep. Same principle applies to laying out circuit boards. Ultimately you want all the grounds in the individual portions of the circuit to directly connect to a single ground point, which in turn goes to the negative terminal of the battery or power supply. When you don't do this, strange things can happen.
Yeah, see? All you have to do is mention the phrase "ground loop", and it'll make any sparky guy of any discipline wretch;-)
 

aznsx

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I'll cogitate on that when my cogitator's working well. Good description.
@IMA SOL MAN

I ran that mental diagram through my cogitator, and the little red light in my head did not come on. Neither did the yellow one. Those lights are pretty reliable. I'm used to having to bet my life on them at times, and I'm still breathing. Based on that, I think it's very unlikely that the setup you describe is an issue to be concerned about, and I would not be if I lived there. That's my simplest / shortest answer - appropriate for a holiday weekend.

Cheers (with an extra helping for the holidays;-)
 

aznsx

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Would underground water mains qualify as a good ground?
Water pipes can make a good grounding point in many situations, and I've seen them used often, and connected system / equipment grounds to them / the grounding bus bars which are connected to them. My primary power exposure has been commercial / industrial, and I've not worked with residential electrical service. I have, however interfaced with it when dealing with communications equipment. Telecom systems / equipment concerns frequently involve grounding. By definition they're often not only sharing common electrical service / grounding, but are also often interconneced by other means as well; thus opening the door for all sorts of the dreaded 'ground loop' issues. I don't know jack about plumbing, but clearly PVC or the like wouldn't work too well - might as well stick a coat hanger in the dirt;-)
 

jabe1

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Plumbing only works well if the service line is copper or steel. Many older homes still have lead lines which don't work.
You also need to use a cold water line because unless a bonding jumper is installed at the water heater, the hot pipes won't be grounded well.
Best is to just have a ground rod installed just outside of where the panel is. A 6' copper coated 5/8" steel rod driven into the ground with #4 bare copper run from it to the ground bar in the panel.

There have been quite a few threads over the years covering potential emp damage to lights I think the general consensus of each has been that it really isn't a concern, as the electronics are generally shielded pretty well anyway. Not to mention the fact that after a true strike you'd have a bit more to worry about than flashlights.
 

IMA SOL MAN

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I have a lot of old coaxial cable that I've been wondering about using for grounding work. Some RG-58, RG-59, RG-8, and maybe some RG-6. All copper braid, I believe. Would connecting the center conductor to the braid be worth doing, or not, due to the skin effect? I'm especially wondering about using the cables for grounding my ham antennas and equipment. I know there are books available on grounding, I just haven't gotten around to acquiring any.
 

aznsx

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I have a lot of old coaxial cable that I've been wondering about using for grounding work. Some RG-58, RG-59, RG-8, and maybe some RG-6. All copper braid, I believe. Would connecting the center conductor to the braid be worth doing, or not, due to the skin effect? I'm especially wondering about using the cables for grounding my ham antennas and equipment. I know there are books available on grounding, I just haven't gotten around to acquiring any.
Well, you done gone went and did it now. You succeeded in making that little red light come on.
 

PhotonWrangler

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An LED bulb and associated driver circuitry are subject to EMP damage, but will usually survive being dropped. An incandescent bulb is resistant to EMP but might not survive a drop. Ask yourself which one is more likely to happen to you.
 

Flynn's Arcade

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Coming from a long line of ham operators, a faraday box is normal. In some aspects looked at much like a fire extinguisher , in that it's monitored, maintained, occasionally upgraded, and hopefully never used :)
FoxFury has a light that is being marketed to address the EMP concern.
Would like to open one up, but at the current price, that's unlikely. Appears to be a simple direct drive type of light engine, but can't be sure.
 
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