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Old 12-03-2008, 12:55 PM   #16
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Will reverse polarity trip breaker??


Sounds to me like current leakage to the coax sheild somewhere along the line, and now the new TV is more sensitive to this and is causing the breaker to trip. I would say as a TEST, wire the outlet back to normal (black to brass [to save your a**] and white to silver) use a 2 prong to 3 prong converter and plug the tv in with that. It effectively "lifts" the ground on the tv; your old tv didn't have a ground in the cord. I suspect that if it works this way, you have an issue with the coax cable. Could be as simple as a bad or no ground at the grounding block on the outside of your house.

To check for a difference in potential between the Coax ground and your electrical ground, use a known good grounded extension cord to a know good grounded outlet (check the outlet ground with a meter) then reference the coax ground to the outlet ground and see what you get. If you get a high reading, go track down that ground block outside your house and see if its got a good ground wire attached to it.

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Old 12-03-2008, 01:15 PM   #17
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Will reverse polarity trip breaker??


A bad, insufficent or improperly wired ground is what I am thinking also, just didn't think about it maybe being in the TV cable. I will try the 3-2 prong adapter test on the TV. Actually I had thought about doing that the other day but already had the heavy as..ed TV cabinet pushed back in place. I will check the cable ground, or maybe even add a new one just to be sure. Thanks so far for all of your suggestions/ideas on this. It's been a real head scratcher. As I get more test information or I find out what the problem is, I will report back here for everyone's future reference.
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Old 12-03-2008, 01:17 PM   #18
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Will reverse polarity trip breaker??


Yes, reverse polarity can both trip the breaker and cause electrical shock. This is much more common with newer equipment as well. Here's why:

In the newer equipment, the connectors are often wired to the neutral wire. In fact, its probably the case that all metal parts on your new TV are directly connected to the neutral wire. I'm not too familiar with TVs, but this is how amplifiers, DVD players, etc are wired. You can easily check this with your multimeter: With the TV unpluged and no where near a socket, and your multimeter on ohms or continuity, connect the multimeter to the big prong of the TV's plug (the neutral). Now try touching metal parts on the outside of the TV. If the metal is painted, you may have to find spots like screws or holes without paint. See if they're connected. The metal might be connected to ground instead.

However, the ground of the connectors are almost for sure hooked up to neutral. Try the same test, with the multimeter connected to the big prong on the TVs cord, and then put the other end on the outside of any connector, like the cable TV input you got shocked from, or the outside of the RCA audio/video connectors. It should show that there is 0 resistance.

Now, the cable company has the outside of their cable connected to earth seperate from the wiring of your house. So with the cable itself connected to ground, when you plug the TV into the wall and plug the cable into the TV, you are connecting neutral with earth, which is okay. Now, if your outlet is reversed, you are making a direct connection from hot to earth through the cable TV connector. Thus, the circuit will be thrown.

Also, when you are going to hook the cable up, if you touch the cable connector on the cable and on the TV at the same time with your hand, the TV is hot and the cable is earth, just like sticking your fingers in the socket - you will get shocked.

So essentially, with a reversed outlet, when you plug that TV in you are making all the metal on the TV (or just all the connectors, depending on the TV) hot. They are just waiting to find any connection to ground, through you touching it through your body, or through a connection like the cable line. Another example is if you have something connected to another outlet that is wired correct. Say, for example, your DVD player is plugged into a different outlet that is wired correct. The audio/video connectors on the DVD player are now correctly tied to neutral. Your TV audio/video connector's outsides are hot because of the reversed outlet. Hook an audio wire between the two, and bingo, a direct connection from hot to neutral. Or, instead of a wire, touch the TV metal and DVD player metal at the same time, and discover a shock.

Older TVs often were not wired this way (and were also less safe when connected to a properly wired outlet).

Lastly, there are many circumstances that can cause a single outlet to be reversed on the whole circuit, some of which were touched upon here. Remember, every outlet (except for the last one) is going to have 4 connections, not just 2. 2 are the connection coming in from the circuit box/previous outlet, and the other 2 are the connections going to the next outlet. If the incoming connections are wired wrong, that outlet will be reversed. If the outgoing connections are wrong, the NEXT outlet will be reversed even though when you look at that outlet, it appears to be wired correct. Also, unless you rip apart the walls, it can be very difficult to see where every single wire goes and it can be easy to miss an outlet on the circuit. Also, you don't know if there's any junction boxes completely inside the walls where the wires are wrong. Even having a schematic of the house doesn't mean the installing electrician didn't screw up, or some previous owner changing things didn't screw things up. Keep looking and examine all 4 connections of every outlet. You also need to know what order they are in, which is difficult as well.
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Old 12-03-2008, 01:23 PM   #19
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Will reverse polarity trip breaker??


Look at it this way... the things you mentioned do not have a ground in their power cords and they are not hooked up to an unwanted energized tv coax ground. This means that when the old tv was plugged in it did not have equipment ground in the power cord and there was not a means for the voltage on the coax to seek a ground path and thereby allowing a current flow that trips the breaker. However you did have an energized chassis...you just didn't know it. You never new because you can't come in contact with it. Now with the new tv you have a connection with the metal chassis of the tv and a connection to the ground of the coax. Their is a potential on the coax which now has a direct connection to the grounded conductor through the chassis of the new tv to the equipment ground of the new power cord. If the coax is energized from the branch circuit serving the tv somewhere this becomes a ground fault that is no longer hidden and the circuit breaker will now trip out once you plug the new tv in to the grounded outlet.
The continued mystery is why changing the wires hot to neutral and neutral to hot or vice versa seems to have hidden this ground fault once the new tv has been plugged in. There seems to be a different things going on either you have a floating ground on the coax that is allowing a potential difference to occur and as soon as you connect it there is current flow or you have an energized ground in the coax . What I'm trying to do is to begin a process to eliminate possible causes that may lead us to the solution.
One thing is certain it is not the new tv but an issue with the premise wiring. If it wasn't then the new tv would not have been tripping breakers you would simply plug it in and go on your merry way.....
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Old 12-03-2008, 02:18 PM   #20
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Will reverse polarity trip breaker??


BoBear and Stubbie:
Thanks for the great input. This is maybe starting to make tracking things down a little easier. Just so I understand, if it is a problem with an ungrounded or improperly grounded coax, if I install a proper ground wire, will that solve the issue? If I use a 3 prong to 2 prong adapter for the TV with the wiring put back to the correct locations on the outlet as Theatretech85 suggested, what does tell if anything about a ground problem? Stubbie - what is a "floating ground"?
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Old 12-03-2008, 03:23 PM   #21
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Will reverse polarity trip breaker??


"Floating ground" simply means ground is not connected to anything. You have all the ground wires in your TV, etc, but they are not actually connected to the earth.

The purpose of the ground wire is almost always protection against a malfunctioning product. The chasis of the TV will be connected to the ground wire (or possibly the neutral instead, as indicated in my previous post). Under a normal operating TV, this means nothing. If for some reason your TV malfunctions and shorts out so that it connects the hot to your TVs chasis, then this is where the ground completes the connection causing the circuit breaker to shut off, thus protecting you from the dangers of a hot chasis as I detailed in my last post.

If everything is wired correctly, and you simply don't have a ground wire on that outlet, then it should not make a difference at all. The only difference it would make is if the TV malfunctioned and shorted out.

The suggestion to use the adaptor and therefore 'float' (disconnect) ground is if for some reason the ground has a voltage on it, or is somehow wired weird into the rest of the system.

Do you have a outlet tester? These are cheap (usually < $10) little devices at the hardware store that you plug into your outlet. Here's an example:
http://www.amazon.com/Gardner-GRT-50...8338878&sr=1-4
This device can quickly tell you if an outlet is wired correctly without having to remember which hole means what and how to stick a multimeter in the socket. I'd suggest getting one of these and walk through your whole house sticking it in every socket, and see what problems arise.

How is your outlet currently connected? Remember, the big slot is neutral, the small slot is hot, and the round bottom hole is ground. When the TV works, what is the voltage from neutral to hot, hot to ground, and neutral to ground? (these correspond with the 3 lights on the tester)
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Old 12-03-2008, 06:52 PM   #22
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Will reverse polarity trip breaker??


Update - When I got home tonight I decided to do some checking on this. I took the switch to the TV outlet out to examine the wiring in the box. Found loose connections under the hot wire nut that opened the circuit when wiggled. Twisted those tight and re-nutted. Also did the same with the white wires. All blacks were hooked together, all whites hooked together and ground wires cut off (geesh!!). Completely unhooked the switch and capped the wire. Re-wired the TV outlet correctly (black to brass "to cover my ass"!!!) Tested with multimeter and outlet tester. Both showed correct wiring but open ground on that outlet. Checked the ground with an extension cord plugged into a known grounded and correctly wired outlet on another circuit. Put a 3-2 prong plug adapter on the TV cord and plugged it in. Happy to report that the TV works OK and does not trip the breaker. That apprears to be telling me that something was/is screwy with the switch setup or ground setup or the catv cable. It was dark when I got home so wasn't able to check for proper ground on the TV cable box outside. Also haven't checked continuity, etc. on cable itself inside the house. Any guesses at this time on what the problem was/is??
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Old 12-03-2008, 07:07 PM   #23
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Will reverse polarity trip breaker??


Just to confirm - you used to extension cord to test the polarity, right?

It's not possible to check polarity via this manner with an open ground.

Also, if you have open ground, then the 3-2 prong adapter doesn't really do anything. (FYI, open ground = floating ground).

You should try without the adapter again. If that causes things go bad, then this ground isn't really open (and that's just scary).
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Old 12-03-2008, 08:05 PM   #24
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Will reverse polarity trip breaker??


Yes I used an extension cord to check for proper connections and ground. With the multimeter in the outlet (without extension cord use) the hot to neutral reads 118 v, the hot to ground reads 0 v and the neutral to ground reads 0 v. Using the extension cord from a known correctly wired and grounded outlet I get: hot on outlet to ground on ext. cord = 118 v, neutral on oulet to ground on ext. cord = 0 v. I will have to try the TV cord without the 3-2 adapter. I thought about that - after I aleady pushed the heavy mother back in place. I also used the little circuit tester on the TV outlet and it shows floating ground.
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Old 12-03-2008, 08:23 PM   #25
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Will reverse polarity trip breaker??


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Originally Posted by Duane 70 View Post
Yes I used an extension cord to check for proper connections and ground. With the multimeter in the outlet (without extension cord use) the hot to neutral reads 118 v, the hot to ground reads 0 v and the neutral to ground reads 0 v. Using the extension cord from a known correctly wired and grounded outlet I get: hot on outlet to ground on ext. cord = 118 v, neutral on oulet to ground on ext. cord = 0 v. I will have to try the TV cord without the 3-2 adapter. I thought about that - after I aleady pushed the heavy mother back in place. I also used the little circuit tester on the TV outlet and it shows floating ground.

How about ground to ground on extension cord?

Test voltage and resistance.
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Old 12-03-2008, 08:31 PM   #26
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Will reverse polarity trip breaker??


Removed the 3-2 prong adapter and plugged TV cord directly into outlet. TV works OK and does not trip breaker (thank you God!!) Does this lead you guys to any conclusions now?? I will still check ground on the catv cable when I get some daylight and time. I don't think I checked the ground on the outlet to the ground on the ext. cord. Will do that also.
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Old 12-03-2008, 09:11 PM   #27
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Will reverse polarity trip breaker??


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Test voltage and resistance.
Of course, make sure you test voltage first. If voltage is 0, then you can test resistance. If you get a voltage, don't test resistance.
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Old 12-03-2008, 09:17 PM   #28
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Will reverse polarity trip breaker??


What should the resistance be?
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Old 12-03-2008, 09:23 PM   #29
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Will reverse polarity trip breaker??


I'll give you my best guess. You say you had an open ground at the outlet or maybe you still have I'm not sure if you corrected that or not. You had a ground fault in that outlet box to the metal box (if it was metal) or metal yoke of the receptacle. It could not clear because of the open ground. Your old tv had no ground wire so the fault could not travel to the tv chassis and ultimately to the tv coax where it then would follow the grounding path to the utility transformer to clear the fault. When you changed to the new tv with a ground wire in the power cord this path was completed to the chassis of the new tv. But it still would not trip the breaker as the fault path back to the source still wasn't completed. When you connected the tv coax the fault path was then completed and the fault current used the coax to return to the source tripping the breaker.
Somewhere in your work you corrected the ground fault and now things are fine.
Thats the best I can do without seeing the situation .
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Old 12-03-2008, 09:24 PM   #30
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What should the resistance be?
Depends...should normally be about 0-1 ohms.

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