Kinda along the lines of my last post, can RG-6 be cut with wire cutters live? I would think not given that even 3 volts (an assumption, maybe much higher) across a few mOhms would create a high current condition; however, I realize that at high frequency, the cable impedance can appear a lot higher (75 ohms to be exact), which does beg the question, can a guy get away with dead shorting a 100' (or much longer really) cable?

Unless the cable is carrying power for something like a downstream line powered amplifier or an LNB on a sat dish there should be nothing but micro volts of RF.

Even if carrying power the power supply is almost always short circuit protected. If you suspect line powering though be nice and disconnect it before you cut, but you probably won't cause a problem if you don't. There is certainly no problem with unpowered cable.

The only case that I could think of that could cause a problem is with the cable supplying an on premises extender amplifier that is line powered by the outside CATV plant. 60 volts AC and there are fuses out there someplace. This usually isn't done very often though.

-Hal

Speaking from experience, if the RG6 is connected to a powered multiswitch for a satelite, don't cut it live!!!

Yes, it depends very much on what is being fed down the cable.

If it's plain RF signals, then it depends upon the power level. I wouldn't want to cut coax live out of a transmitter as it may well damage the final amp stage.

As for cables with superimposed DC power, I know somebody who got so fed up with a cable-TV company that kept billing and wouldn't disconnect the service that he decided to disconnect it himself. It took out the CATV power to whole block!

So, Trumpy, did they disconnect him then?


(Edited to add: I thought I recognized the accent, but I was just a little, teeny bit off--I meant Paul.)

[This message has been edited by SolarPowered (edited 10-18-2004).]

No problem cutting coax live or not. What is important, at least in my industry, is to use special coax cutters as not to deform the coax.

Trumpy? I know we're both those Commonwealth guys with the funny accents , but I reckon that was aimed at me.....

Yes, they finally got the message!

"No problem cutting coax live or not. What is important, at least in my industry, is to use special coax cutters as not to deform the coax."
___________________________________________

What industry is that? Cut my coax when i am operating CW and you will light up.

LK, good point I should have qualified my statement with low power line level signals. I am in the Telco buisness, and we mostly deal with DS3, some micro and a lot of wireless telephone. Yes if you were to cut a coax with a transmitter on it you could get burned.

One place I was at had an prize of shame for the bigest mistake. I remember one guy got it for cutting a RG-6 for a home sattilate system. I guess it burned out the dish reciever.

Tom

Speaking from experience, if the RG6 is connected to a powered multiswitch for a satelite, don't cut it live!!!... I remember one guy got it for cutting a RG-6 for a home sattilate system. I guess it burned out the dish reciever.

Not that I disagree with you guys, but it is very common to short cables in these systems. You don't have to even cut them, simply connecting or disconnecting an "F" connector can short the line and it is not usually possible to shut everything down to do it.

Any equipment that I have ever seen is protected in this respect and most good sat receivers will even indicate a problem with the LNB power such as a short in the cable.

-Hal

You can probably get away with it but why would you? I think an attitude that 'it's a low power circuit so I don't have to worry' will get you in trouble some day when you encounter an unexpected fault.

You can probably get away with it but why would you?

Because it's not as easy as flipping a breaker.

If it's unpowered there is absolutely no reason to do anything other than cut it. What are you going to do, go to where the CATV service enters the house and disconnect it? Why?

On the other hand, you know that the cable in question MAY be powered if you see a dish and sat receivers. But here again, what are you going to do- go around the house and pull all the plugs on the receivers? Would you know what a powered multi-switch is? Sure, if you knew where the cable originated you could disconnect it carefully... or kill the main breaker, that'll do it!

-Hal

I guess you won't be doing any communications work in my house. It sounds like you are saying you don't know or care where the ends are and you'll hack it anyway. Would you know or care that a piece of coax in my house might have 1/4 kw of RF on it?
I'd have to know what it was for sure before I go hacking.

Darned good point Jim.
That's gotta ruin your sidey's!.