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Running phone line thru UPS

T

TwoBills

Senior member
I was just talking to an associate regarding some pros and cons of UPS devices. Bottom line, and he got this from a very informed source, running your phone line thru your UPS can cause more problems than solutions.

It goes something like this: If you take a major spike on your AC, and your phone line is plugged into the UPS, the spike can arc to the phone line, on the wrong side of the clamp. Not to mention it's on the wrong side of the phone company's movs.

Something to think about. Just thought I'd pass it along.
 
I've never plugged my phone into my UPS/surge protector anyway. Aren't phone lines separate from power lines and therefore don't need "surge protection"?
 
Many a modem has been toasted by lightning pulses coming in over the phone line often along with other parts. I use the phone line protection on my surge protector - just one more line of defense. But you should do your own tests. If you get just as good connections thru a protector as direct to the wall, then use the protector. If worse connections, skip it and just unplug the phone cord from the wall when you'll be away and when lightning storms are in the neighborhood.
..bh.
 
Originally posted by: RaiderJ
I've never plugged my phone into my UPS/surge protector anyway. Aren't phone lines separate from power lines and therefore don't need "surge protection"?
Click to expand...

Yes, but:

they still come off the pole, so the lightning could take the phone line;

if the phone or answering machine is plugged into power that gives it access to the electrical lines;

related to the first point, if a phone line is going direct to your modem (either dialup or DSL), those are both connected to your computer. This also applies to cable--i.e. it still is plugged into a cable modem or your TV, so you need to protect that possible path as well.

I've seen in a house that had underground utility service, a lightning strike a block away take out a garage door opener (melted), a couple of NIC cards, router, and cable modem (fun to troubleshoot that 🙂 ).

And everything there was properly grounded (well, phone & cable were grounded to electrical which appeared to be done right).

Have also seen the aftermath of direct hits, RE boxes blown off walls, exploded pipes, fried electronics, basically not good things. I unplug my computer from the wall and unplug the cable from the cable modem when a thunderstorm comes in.

EDIT:
Oh, and insurance is your friend. I'm working on getting renter's insurance at this point.
 
Jeez, you guys missed the whole point. I was talking about running your phone line thru an Uninterupted Power Supply!

Let's see if I can make the point: Lightning spikes the UPS, well your going to lose the UPS, but probably save the computer. And let's say the phone line is coming into the "house" by a totally different path, underground for instance. Well, it might not be spiked, unless it's plugged into the UPS. That's where the phone line is hit. At the worst place possible. On the "south" side of the mov's that the phone company provides (had yours checked lately?) and on the "south" side of the surge protection you were trying to take advantage of, if you ran your phone line thru the UPS. Nothing between the spike and your computer, and possibablly your ear. Same goes for running your cable thru the UPS or a combo A/C and cable surge protector.

Grounding is a very funny thing. Connecting to the electrical ground can cause an antenna/lightning rod effect. Same with running UP to a cold water pipe. The only proper ground is down, no more than 10', with gently radiused turns, attached to the incoming cold water pipe or it's own grounding rod. No ground is better than an improper ground.

That's it. That's all I've got.
 
Telephony/data VSP on consumer grade UPS' is nothing more than an eight position modular jack connected to a PCB with a few MOV's across the lines! Take one apart and see for yourself...

IF a surge is strong enough to overwhelm your NID and (in the case with electric delivery) the average breakdown between planes (~4.5kV) you have much more to worry about than your precious computers and big screen tv's.

Yes folks, I've witnessed the direct hit to the line and it isn't pretty. Enormous amounts of energy are delivered at once and it has to find a path to ground. In severe cases, it blows the faucets off your kitchen sink, shears the hands off an electric wall clock and blows out the tires in your car that's sitting in the garage due to the reinforcement wires in the concrete slab! You know what that does to people? We call it getting the new look. Luckily it doesn't hurt too much.

Cheers!
 
The phone jacks on the UPS are separately surge protected with their own set of MOVs or perhaps Transorbs (even better) or both. They have nothing in common with the rest of the UPS circuitry except for connecting to the same earth ground internally. It's the same with most surge protectors - the AC and the phone jacks are separately protected circuits.
. Most UPSs will have the equivalent of a good separate surge and RFI/EMI noise protector built into it on the AC input (wall) side of the unit. There is none on the AC output side - the regulator circuitry is supposed to take care of that.
. Some with a "belt and suspenders" mindset will add extra surge protectors to either or both sides of a UPS...
.bh.

:moon:
 
It's the common ground, inside the UPS, that I was talking about. That's where the problem lies. A hit on the AC, not a direct hit, all bets are off then, can be transfered to the phone line, thru the common ground, and hit the computer before it can be clamped.
 
Lightning energy (static) takes the least resistance path to earth. The least resistance path is NOT back thru the MOVs into the phone jack contacts. IAC, it doesn't matter as ALL grounds in a house are the same unless you run a separate wire to a "metal into the ground" cold water pipe or ground rod.
.bh.
 
correct, electricity is not "smart" it takes the path of least resistance, which is straight to ground.

its not going to magically pick to go in the phone line since there is resistance in that path (phone itself)

now if the entire system is not properly grounded, then you would have problems before a strike would have the chance to cause trouble.

side note: i lost my dsl modem to that dam seperate 45V power source that phone companies use =(

$100 down the drain, and I dont even use old time phones that use that voltage.
 
No, the electricity is not smart. It takes all the paths, and will flow with different intensities on different paths. The intensities varies with the inverse of the resistence.

Calin
 
Originally posted by: Calin
No, the electricity is not smart. It takes all the paths, and will flow with different intensities on different paths. The intensities varies with the inverse of the resistence.

Calin
Click to expand...
Exactly, and given the UPS has a solid connection to ground, an insignificant amount of current will take any path other than that one.

If you're in the habit of cutting off the third prong on your plugs, you'll have issues 😉
 
Thankfully in NYC our POTS lines run underground. I used to (pre-broadband) run my phone line thru my UPS but would always hear a hum when I was on the phone so I took it off. When we had the blackout last year the only thing working was the phone. I never trusted running a phone line thru the UPS as I have seen phone lines actually trip the ups because when you get a phone call the voltage is quite high during the ring than it is when idle. I have several friends whos UPS' tripped constantly when they received calls. Then again they had so much connected to the ups the a phone call would push it over the edge.🙂
 
Originally posted by: TwoBills
I was just talking to an associate regarding some pros and cons of UPS devices. Bottom line, and he got this from a very informed source, running your phone line thru your UPS can cause more problems than solutions.

It goes something like this: If you take a major spike on your AC, and your phone line is plugged into the UPS, the spike can arc to the phone line, on the wrong side of the clamp. Not to mention it's on the wrong side of the phone company's movs.

Something to think about. Just thought I'd pass it along.
Click to expand...

so, you are saying a UPS has less surge protection than a cheapo surge protector? too bad, I was going to get an UPS to guard against both surges and brownouts...
 
I've often wondered why they don't use optocoupler circuitry to isolate the phone line from the modem circuitry, I guess it's just too expensive...
.bh.
 
Zepper, interesting point. Now that you mention it, I thought that was required. Pretty much all of the (older) modems that I've looked at, have the PCB divided, with all of the phone-interface analog on one side, and digital/computer stuff on the other, connected together with this one larger 4-pin DIP device. I thought that was an optocoupler, myself.

My personal belief on this matter of UPSs and cable/phone lines - what if the lightning strike is nearer to the phone or cable lines, than the AC? I would much rather that such a strike, attempt to be shunted to the earth ground of the AC line if possible, and that's one thing that a good cable/phone/AC surge or UPS should do.

If you directly connect your computer to cable/phone, but have your AC protected by a surge/UPS, what good does incomplete surge protection really do?

And if it's a "direct strike", there's really not much you can do in that case anyways, it's well known that UPSs cannot and do not protect from direct lightning strikes, that's what those warranties are for. So that is a non-argument for not protecting your cable/phone connections like your AC connections.

I'm curious about who this "very informed source" was. I'll have to bounce this question off of some EEs and see what they say. My gut feeling is that complete-but-imperfect surge protection is better than incomplete-but-imperfect surge protection. (And if anyone knows how to achieve "perfect" surge protection - protection from direct lightning strikes without ever taking any damage - I'd certainly like to hear it. 🙂 )
 
I'm curious about who this "very informed source" was. I'll have to bounce this question off of some EEs and see what they say. My gut feeling is that complete-but-imperfect surge protection is better than incomplete-but-imperfect surge protection. (And if anyone knows how to achieve "perfect" surge protection - protection from direct lightning strikes without ever taking any damage - I'd certainly like to hear it. 🙂 )[/quote]


This info. came from Wade Moose (Hickery, NC), who is one of the leaders in grounding and lightning protection, as far as I am concerned, in the private security industry. He was the manufacture of Moose Z1100 security controls, that was considered one of the best in the industry, as far as advanced lightning protection technology. I've seen a Z1100 take a direct hit (with a "proper" ground) and still operate (after a reboot). The grounding plane was blown out but the system still worked.

I've been following his advice for over 15 years and it's never failed me. Basically it's "no ground is better than an improper ground". Following this advice, I have solved numerous ground related problems over the years, when so called experts were blindly following their "educated" paths to no avail.

I'm just an old dog, in the trenches for over 30 years, and maybe I can't convey my instintive knowledge very well, but if I put it out there, you'd be best served to close your books and pay attention. And if it comes from the desk of Wade Moose, now the manufacturer of Elk security systems, it goes double.
 
Perfect protection from a direct hit can be had via a Faraday cage, battery power only and optically isolated communication connections. Of course lining and bonding the entire perimeter surfaces of your house with heavy copper mesh migh be impractical... 😉
. A similar effect can be had in an Airstream travel trailer or any space with a cotinuous metal shell - a typical metal-bodied vehicle (others like Corvettes are another story) offers excellent lightning protection as long as you don't touch any metal during the strike(s). That's why no one in most airplanes will die from a lightning strike unless it causes the plane to crash...
.bh.
 
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