Hi list,
Someone told me that it is normal for devices (TV's etc) to put a current on the shielding of the TV-cable. Is this true? Is this also true for certified devices?
Halfgaar
-- To send me, Halfgaar, email, remove remove from my email address.
Huh? I must be missing something, because I can make no sense out of your post.
Do you understand how a coaxial cable functions?
Harry C.
post.
Leakage current from the equipment, flowing to ground through the shield of the coaxial cable.
-- Michael A. Terrell Central Florida
Appliances should never put current on coaxial cables. For example, the TV antenna input is typically galvanically isolated. Only the high frequency signals - trivial current - should pass between TV and cable.
However leakage currents can exist. Currents > Someone told me that it is normal for devices (TV's etc) to put a
No, it is not "normal", it may occurr more often than desired, but it is NEVER inentional. In some circumstances, it is actually LETHAL.
If you have a specific situation you are dealing with BE VERY CAREFUL. If you are looking for responses to something that is happening in real life, by all means ask specific questions rather than dancing around the theory. Else you may end up more knowledgable, but dead.
post.
I did a building-to-building link for GenRad in the late '70's using RG8... there was only a hard ground on one end and a high value resistor on the other end to ground, with transformer-coupling and DC-restore. There was about 15V difference in ground potential between the two buildings (300' apart).
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
This be Arizona... there is no "earth" ;-)
Touch-grounding the far end and drawing sparks caused me to choose the method I did.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
coax grounded to the same earth as AC by code? I don't think that's the case here, I wouldn't know where. The cable doesn't enter the house near the breakerbox. There is a difference of almost 0 ohms between coax ground and AC ground, but I suppose that's because there's grounded equipment connected to the TV-cable.
Halfgaar
-- To send me, Halfgaar, email, remove remove from my email address.
Not to worry, I haven't been shocked by the cable here. The TV-cable here is grounded to the AC ground, but I don't see how (see my reply to w_toms's message).
Halfgaar
-- To send me, Halfgaar, email, remove remove from my email address.
National Electrical Code makes these demands for human safety: Article 820.33
Article 820.40A Grounding conductor
Clearly, without visual > coax grounded to the same earth as AC by code? I don't think
As I said, I can't see that's it's grounded, so it probably isn't. I'll see if I can ground it. Thanks for your help.
Halfgaar
-- To send me, Halfgaar, email, remove remove from my email address.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.