Quad-shield RG6 and electric wire

[iammike]

My mother is having a sun room added on to the back of her house and will be using a Dish network 722 receiver in the room. I asked the electricians to run 3 runs of coax and one cat5e to each potential TV location in the room. I also asked them to try to keep it separated from the electric wiring they placed in the room. They kept the electric in separate holes in the room, however on the long run (around 100ft.) from the new room to the electric panel in the garage they ran the cables essentially in a bundle. Not only are they not separated, but they're actually touching most of the way.

They did use quad-shield RG6, but I'm concerned about the potential for interference on such a long run. Should I make them go back into the attic and tack the coax and ethernet to the rafters, or am I making too much of it? She'll have the feed from her satellite dishes, her attic antenna, and the TV2 output from the receiver running on the coax.

Thanks for any suggestions!
Mike

 

[nelson61]

Why don't you connect up and make a temporary hookup with a receiver and tv and test reception. Be sure to have the electrical line live also. You will know immediately if you are going to have interference

 

[iammike]

Why don't you connect up and make a temporary hookup with a receiver and tv and test reception. Be sure to have the electrical line live also. You will know immediately if you are going to have interference

I could hook up the coax, but the electric wires won't be energized until the walls are closed up. Thanks for the idea though.

I did talk to one of the communications guys here at work this morning. He didn't think there would be a problem, but wasn't totally sure. He runs ethernet and phone lines not coax.

 

[AllieVi]

You have a couple things going in your favor. Quad-shield coax does a good job of rejecting interference and the 60 Hz power-line frequency isn’t likely to cause serious problems with MHz/GHz signals.

Any induced signals would be directly related to the current in electrical circuits. If they are lightly loaded, little effect will exist.

Having said all that, mixing signal and power cables is generally not a good idea. Keeping them separated eliminates the (very remote) possibility of 110-volt power getting on the signal cable (e.g., a mouse chews through the insulation on adjoining signal and power conductors).

 

[iammike]

You have a couple things going in your favor. Quad-shield coax does a good job of rejecting interference and the 60 Hz power-line frequency isn’t likely to cause serious problems with MHz/GHz signals.

Any induced signals would be directly related to the current in electrical circuits. If they are lightly loaded, little effect will exist.

Having said all that, mixing signal and power cables is generally not a good idea. Keeping them separated eliminates the (very remote) possibility of 110-volt power getting on the signal cable (e.g., a mouse chews through the insulation on adjoining signal and power conductors).

Thanks for the info! Sounds like you really know your stuff. Your mention of lightly loaded circuits not having much effect kind made think of something else going on at my mother's place. When she runs her microwave, the picture on her kitchen TV can get a little flakey. I know the coax in her kitchen is also running parallel to electric wire, and I'm pretty sure it's not quad-shielded. Would that be a heavier load causing interference or just the fact that it's a microwave?

 

[AllieVi]

Thanks for the info! Sounds like you really know your stuff. [Fooled ya'! ] Your mention of lightly loaded circuits not having much effect kind made think of something else going on at my mother's place. When she runs her microwave, the picture on her kitchen TV can get a little flakey. I know the coax in her kitchen is also running parallel to electric wire, and I'm pretty sure it's not quad-shielded. Would that be a heavier load causing interference or just the fact that it's a microwave?

Microwave ovens heat food by generating MHz frequencies that can interfere with cell phones, wireless networks and other electronic equipment that operates in those frequencies (the innards of TV’s do). Even though the current load in the microwave circuit would be high, the culprit is more likely microwave energy escaping the oven.

 

[iammike]

Microwave ovens heat food by generating MHz frequencies that can interfere with cell phones, wireless networks and other electronic equipment that operates in those frequencies (the innards of TV’s do). Even though the current load in the microwave circuit would be high, the culprit is more likely microwave energy escaping the oven.

Well, now you've fooled me twice. That sounded like a pretty reasonable explanation to me. Thanks again!

 

[cparker]

Power and signal wires should be separated in parallel runs. Quad shield will *probably* be fine, but why tempt fate? The ethernet runs should be separated from the power runs as well. Rule of thumb is to keep parallel runs 24 inches apart (keep signal runs 24 inches from power runs) and when you DO have to cross a signal line past a power line, you do it at right angles.

Can you get away with not separating them? Maybe. ... but again I'd ask, why tempt fate? If you DO have problems they can show up in very odd and seemingly random ways and can make you pull your hair out. I am refurbishing a house that has a low voltage lighting control system. Geeky and fun, but if not done properly you can actually have lights turning on and off seemingly by themselves.

Rule of thumb. Separate power and signal runs. An electrician should know better than to group them like that.

 

[AllieVi]

... An electrician should know better than to group them like that.

Good electricians do, but the temptation to save time by drilling only half as many holes sometimes gets the better of them...