Coax Grounding question -- Help!

[ktalley]

(I had originally posted this question at the end of the LONG thread "Okay to not ground coax feed from dish...", but decided to move to a new thread instead -- I posted a follow-up to that effect in the other thread. Sorry for the confusion!)

Sad to report that my two DP301s were apparently "zapped" a couple of days ago by a severe electrical storm. The receivers power on, menus look okay, etc., but neither sees the satellites now -- AND Check Switch on both receivers now reports "no switch found". I tested with a borrowed DP301 and check switch runs fine on it, so it must be receiver(s) problem -- not a problem with dish/LNBs, or cabling. I removed covers to take a look inside, but don't see anything obviously "wrong" (charred or bubbled!). Obviously, that still doesn't mean that some component didn't get zapped -- which must be the case here.

This is a relatively new house, and yes I originally purchased the grounding blocks (etc.) for my dish install, but just HAD to go ahead and wire everything up (to watch TV) until I could find the "few hours" for my "proper grounding" project. One week led to one month -- one month led to a few months -- you get the picture. Time passed, and I never grounded my dish(es). Now, I'll pay the price (two DP301 receivers, two wireless routers, HDMI input on my 4-week old 42" plasma TV, power supply on my Media Center computer, and probably some yet-to-be-discovered things).

Lesson Learned. Now I must ground, and ground CORRECTLY!

Both of my dishes (Dish 500s) are 200-300' from point-of-entry at my house (I am surrounded by tall trees). One dish (single cable) enters the house thru same access "hole" as phone line (which is right beside my electrical main/meter). FWIW, I also have an outdoor wireless (802.11b/g) antenna that must be grounded (I have an arrestor block for this also) -- it also enters the house at this location. So I have 2 cables here that must be grounded. Can I simply attach these ground blocks (using #10 solid copper wire & a bolt clamp/connector) to the thick (#6?) copper wire (visible -- partially in a conduit) that runs down the outside wall from my electric meter/box into the ground (the phone box ground wire is already connected to this -- at topsoil level)?

The other side of the equation is that my other Dish 500 (2 cables - dual LNB) is on the other end of the house. Those 2 cables currently enter my crawlspace/basement on THAT end of the house. I had originally intended on driving a grounding rod (at least 4' -- this is very rocky red clay...I've read that clay is very conductive and shorter rods will work okay) on that end and using a dual grounding block -- then just let it run on thru the crawlspace/basement to my cabling "hub" (where the other cables enter the basement). But now I'm reading all of this about "you must connect all earth grounds", so I'm thinking I'm about to do something wrong? Must I connect my grounding rod to the other end of the house? If so, can I just run a long piece of #10 copper wire along with my 2 coax runs and connect it to the ground on the other end of the house (basically, go in the basement and come out the other end of the house)? Or should I just run the 2 coax cables straight under the house (no grounding block at point of entry) THEN out the other end of the house, ground them (along the 2 mentioned above), and then BACK into the basement (for connection to various TVs etc.)? On the surface, that approach sounds a bit dangerous ("inviting" the lightning charge to run thru the length of the basement and hope that it will exit nicely!).

My questions may sound a bit confused -- if so, it's because I'm NOT an electricity/lightning expert!!

Basically, it boils down to two questions -- (1) can I connect to the electric meter/box copper ground wire (using the wire clamps) and accomplish proper grounding? (2) how is the best way to ground the 2 coax cables coming into the opposite end of the house?

THANKS MUCH!!!
Kevin T.

 

[Van]

Per NEC guidelines any additional ground rods must be atached to the structures primary ground source by way of a #6 gauge wire.

A ground must be 8 foot in the ground, not 4 foot or 6 foot ( rules you know ).

Each grounding wire must have its own grounding device/clamp.

You could run the 2 wires straight through the crawl to the opposite side where the ground is and the switch is and ground the coax before the switch.

 

[ktalley]

Thanks for the info, Van...

If I can *safely* run the 2 coax cables thru the crawlspace (and ground them once they exit the house on the other end), then I really don't need the grounding rod, so that takes care of that situation.

Is it acceptable to attach all 4 of these grounds (3 dish coax, 1 wireless coax -- each one individually attached w/cable clamp) to the exposed #6 copper wire running down from my electric box/meter (as my phone box is currently doing)? Most of it is inside a conduit, but there's about 6-8" above the ground that is exposed (the phone clamp is right at soil surface level).

Thanks again for your help...

 

[miguelaqui]

When I worked in cable....

I saw lightning hit, then was black at every clip all the way to the ground block. Then, melted the ground block...

After that...we had to ground before entering the home.

I REALLY NEVER UNDERSTOOD THIS.....
Most ground blocks only ground the shielding....what happens when the overload is on the center conductor?

 

[Van]

If you have 3 foot of the copper structure ground wire accessable then you can have a clip for each inch of the wire.

As long as the coax is not within 4 foot of a source that could allow the current from the lightning to arc then it shouldnt be a problem. A house that I worked on 2 years ago took a hit to the utility pole outside and the strike came down the phone wire and electrical into the house, it did an arc of 2 foot from the phone nid outside to the coax at an ungrounded block and followed in to a splice and then arced over 6 inches to the coldwater main and out.

 

[harlanba]

No Grounding Block Was Not the Cause of All That Damage

I would bet money that all of that equipment damage described was not caused because the satellite coax was not grounded. More than likely it was a surge thru the main eletrical power that could have been much better prevented by isolating all the sensitive electronics including TV on a UPS. I use two UPS's in my home theater and nothing even blinks during storms or power outages. I actually fixed my VIP622 from dropping signals and the check switch errors by removing the coax ground block. Its probably a good idea to use a grounding block if its doesn't cause other issues but its not going to save anybody from a lightning strike.

 

[SmityWhity]

I agree that a surge protector may have saved the equipment, especially a combination UPS/surge protector.

However, backing up and trying to sort through the scenario.... It's been several years since I found a NEC booklet laying around and read it (a mind is a terrible thing to waste), and I am not a licensed electrician, so here is some thought for what it's worth.

I thought the NEC says the cable should be grounded as close as practical to the point where it enters the building.

I wouldn't think that means to go through the house to the other side. And I'm sure there are a few exceptions.

I believe the theory behind a grounding block is the current will jump from the coax to the ground conductor.

Possible Option?: IRT the 2 dishes on the other end of the house, is there a metal water pipe/faucet there that these 2 dishes could be grounded to?

 

[ktalley]

harlanba:
Well, in this particular case, it HAD to be the coax, because I had unplugged the TV (AC) before the storm started! Having said that, I *do* already have all home entertainment pieces plugged into a high-end UPS/Surge box. But I would hesitate to make the statement "it's [grounding block] not going to save anybody from a lightning strike." -- do you know this for a 100% certainty? I had grounding blocks at my old house (500 yards away) and NEVER had issues (over 3 years). I (because of laziness) did NOT install grounding blocks at my new house and have been hit twice in the past 3 months (each time suffering major circuit damage to my plasma TV -- the second "hit" wiping out both DP301s -- and I'm confident the culprit travelled via coax).

SmityWhity:
Yes, I tend to agree -- I just couldn't get a "warm & fuzzy" about letting the cable run thru my basement and then out the other end for grounding. I ended up simply driving an 8' grounding rod on the opposite end of the house and grounding the two coax cables from dish #1 to that rod. And, no, it's NOT connected to the main ground rod (80' away at the other end of house) per NEC recommendations, but this is the best I can do (for now). Maybe someday (soon) I'll order another 500' spool of burial-grade cable, rent a trencher, and re-run both of those cables AROUND the house to the primary ground point. Unfortunately, moving the dish is just not an option (due to line of sight).

There's thunder rumbling in the distance (as I type). I just got my 2 new DP311s activated last night, so the true test may be coming soon!!!

Here's a question -- does anyone have any experience with those high-end APC surge protectors with the coax ports (clearly labelled Cable/Sat) and ethernet ports? I bought one of those a few days ago (thinking it might give me an added layer of protection), but couldn't get the receiver to "see the birds" correctly until I bypassed the surge protector. It would partially work -- sometimes I'd run Check Switch and it would look fine, and then 3 minutes later I'd lose signal completely. Since I bypassed, everthing has worked perfectly. Bummer -- I guess this is going back to the store (although the ethernet part is working fine -- perhaps it's worth $50 to have more protection at my point-of-entry for home network from my outdoor 802.11b/g wireless antenna).

Thanks for ALL of the input on this issue!
Kevin T.

 

[Mike500]

harlanba:

Here's a question -- does anyone have any experience with those high-end APC surge protectors with the coax ports (clearly labelled Cable/Sat) and ethernet ports? I bought one of those a few days ago (thinking it might give me an added layer of protection), but couldn't get the receiver to "see the birds" correctly until I bypassed the surge protector. It would partially work -- sometimes I'd run Check Switch and it would look fine, and then 3 minutes later I'd lose signal completely. Since I bypassed, everthing has worked perfectly. Bummer -- I guess this is going back to the store (although the ethernet part is working fine -- perhaps it's worth $50 to have more protection at my point-of-entry for home network from my outdoor 802.11b/g wireless antenna).

Thanks for ALL of the input on this issue!
Kevin T.

There is a difference between a cable and a satellite surge protector. A very high end cable surge protector will not pass more than five volts DC. A satellite rated surge protector will pass up to 27 volts.

I'm not familiar with the APC surge protector, but I am almost sure that it is not passing the lnb power voltage or switching signal.

 

[bhelms]

...I'm not familiar with the APC surge protector, but I am almost sure that it is not passing the lnb power voltage or switching signal.

Or it simply might not be suitable to 2150MHz (too lossy at the higher end of that down converted band, or whatever)...

 

[harlanba]

Grounding Block Not Going To Save You

A typical lightning bolt contains 1 billion volts and contains between 10,000 to 200,000 amperes of current. How long is that 8 ga ground wire going to carry that kind of load before it melts and then the load proceeds down the coax anyway? Probably less than a second. A grounding block is useless against a direct strike. Period. I've had satellie dishes for 25 years and have never had a grounding block nor a problem. Besides why would you need to worry about a grounding block now for. Lightning never strikes in the same place twice.

 

[bhelms]

Yez rolls the dice, yez takes yer chances...

Agreed there's not much that a consumer can economically install that will protect from even a modest direct strike. But there are quite a few "close" strikes that might cause damage that just might be avoided with correct grounding. It's cheap insurance against those eventualities. Speaking of insurance, what will YOUR homeowner's insurance company say when you file a claim for lightning damage that apparently entered through your antenna/dish system and the adjuster finds that you did not have the system grounded ?? (You might want to ask them before it actually happens...!)

Besides - a properly grounded system is protected against other potentially damaging or performance-degrading phenomena such as static and induced emf.

Ask someone with offices in the Empire State Building how many times a year it gets struck - I'll bet it's a bunch more than twice! (I realize you were joking about that.)

YMMV...

 

[bhelms]

...I REALLY NEVER UNDERSTOOD THIS.....
Most ground blocks only ground the shielding....what happens when the overload is on the center conductor?

Something I've wondered about as well! Actually, the answer is obvious. The real question is what can be done about it, as discussed here...

http://www.satelliteguys.us/showthread.php?t=68719&highlight=spark+gap

BRgds...

 

[cali_installer]

i have worked for dish network going on four(4) years now and atleast once a month we argue over grounding, which is a losing battle since i have worked for an electrical contractor for ore than 10., lightning thru a number #10 or #6 wire on a direct strike to the dish would fry your electronics and melt the wire,the grounds we use for satellite isnt for that its because the dish sits outside and pics up a static charge in the wind and for a surge in your home electrical wiring,it you were grounding to stop lightning most of us would never get satellile just because the cost of the wire needed ... i have seen direct strikes in georgia and indiana and both times the sat boxes was burned the the coax/dish destroyed and the 7 foot poles they were mounted on were melted..., our office didnt start complaining about grounding til a insurance company denied a claim to a customer when his home caught fire and was blamed on electrical when was then pushed off to us by the dish/lines not being grounded the fire started by his tv

 

[Mike500]

i have worked for dish network going on four(4) years now and atleast once a month we argue over grounding, which is a losing battle since i have worked for an electrical contractor for ore than 10., lightning thru a number #10 or #6 wire on a direct strike to the dish would fry your electronics and melt the wire,the grounds we use for satellite isnt for that its because the dish sits outside and pics up a static charge in the wind and for a surge in your home electrical wiring,it you were grounding to stop lightning most of us would never get satellile just because the cost of the wire needed ... i have seen direct strikes in georgia and indiana and both times the sat boxes was burned the the coax/dish destroyed and the 7 foot poles they were mounted on were melted..., our office didnt start complaining about grounding til a insurance company denied a claim to a customer when his home caught fire and was blamed on electrical when was then pushed off to us by the dish/lines not being grounded the fire started by his tv

That's why I always ground everything to code.

 

[shodobe]

I recently had my system upgraded to the 1000. The tech took out the sw-21 switches, said I didn't need them anymore and the system is now without being grounded. I noticed he did ground the coax dual wire directly to the dish. It doesn't seem to go beyond the next spliced in wire that goes directly to the house. I am in the process of moving my dish to get better reception due to a large tree that has leafed out very well. The 500 dish had no problems with this tree but this 1000 seems to be very sensitive to obstruction. My reception on most transponders are sometimes below 50% and I loose reception alot especially during the day. How would I ground the dish? I thought driving a grounding rod next to the post and running a large gauge wire to it would be helpful. I live in NorCal and might get a thunderstorm once a year. Thanks

 

[Van]

Dish got into the big push on grounding after an apartment complex caught fire during a thunderstorm in kansas city back in 01 and there was a dish on the building, investigators determined it was a wiring problem in the laundry room but dish went monkey nuts on grounding since then though I know of some management in california, florida, georgia and michigan that will look the other way and will tell techs to not ground a system such as when there is a big deadline looming just to name a few, live in an building that doesnt have readily accessible grounding and your in one of the above locations then your system will get installed without grounding.

 

[webbydude]

Yes, that's pretty much the "unofficial" policy here in Ohio as well. If it's an apartment install, the RSP will turn the other way with regards to grounding. But we still have to document it and have it placed in E-connect notes

 

[cali_installer]

ok since the topic is now on apartment grounding how would you do it if your in a apartment as many here in california your only option may be grounding to the A/C condenser which can be on a central electrical feed and on a seperate circuit per unit and not connected to your panel do u ground to it knowing al the A/C's have a electrical panel dedicated to them?

 

[Claude Greiner]

Speaking of that, I just repaired an old model 4000 the other day that got zaped during an electrical storm.

The only thing bad was the power board, which I was able to swap from an old ISD 2300.

Switched the board and the old 4000 works as good as new!