HDMI Cable tripping my circuit breaker

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  #1  
Old 08-23-18, 06:28 PM
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HDMI Cable tripping my circuit breaker

Hi all,

First post here. I recently bought a 25ft HDMI cable (https://www.monoprice.com/product?c_...seq=1&format=2) to use from my computer to my TV.

I went to plug it in, and as soon as metal touches metal, the circuit trips. I've tried a series of combinations and it's always the HDMI cable that's the trip.

What's causing this? Is it the cable itself? My TV? Computer? Everything else works fine.

Thanks for any help/suggestions!!
 
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  #2  
Old 08-23-18, 06:41 PM
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Welcome to the forums.

Ultimately.... it's most likely the TV causing the problem. You WILL need a meter to check for the problem. I would highly recommend not trying different combinations to see what works. It is not the HDMI cable causing the problem.

Do you have cable TV hooked up to the TV thru a set top box ?
Is that working ok ?
Are you trying to connect a desktop computer or a laptop that uses a power cord with three prongs into the wall ?


The sparks you are seeing is live power where it shouldn't be and the connection to ground thru the HDMI cable and computer.
 
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Old 08-23-18, 06:46 PM
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Hi,

The cable TV is hooked up through a shaw cable box.
The TV/cable box/computer all work fine with the HDMI cable disconnected.
Yes, it's a 3 prong plug.

When the circuit tripped the first time, neither the TV nor cable box were plugged in, so I plugged the HDMI cable into the powerless TV and it tripped. It's still the TV causing it?

When you say meter--what do you mean specifically?

Thanks!
 
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Old 08-23-18, 06:51 PM
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Yes..... the computer has a three prong plug...... correct ?
That means the computer is grounded as well as the end of the HDMI cable.

That also means the problem is with your cable line since you had the TV unplugged. The cable line is supposed to be at ground potential. Apparently yours is not. You would need a voltmeter to check for 120vAC between the cable line and ground. You could check from the metal connector to the ground pin on the receptacle.

Another problem could be that the ground pin on the receptacle where you plugged the computer in is not grounded and is live. I'd check the cable line first.
 
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Old 08-23-18, 06:57 PM
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Yes, the computer has a 3 prong plug

The cable line, you mean the HDMI cable?

The voltmeter is the same meter you were referring to earlier?
 
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Old 08-23-18, 07:12 PM
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By cable line...... I mean the cable TV line that goes to the cable box.
Yes..... meter and voltmeter are the same thing.

You could probably use one of those non contact testers if you have one.
 
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Old 08-24-18, 05:23 AM
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A word of CAUTION.

A word of CAUTION. It's possible your electric service has a compromised neutral. IF that's the case, a properly grounded CATV cable could be providing at least part of the return path for your house. This condition may be accompanied by some incandescent appear bright.


While return voltage on the CATV cable should not dangerous (or your CATV box would be fried), use caution.
 
  #8  
Old 08-24-18, 06:16 AM
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If the circuit is tripping, you've got a fair amount of amperage, which is worrying.

I've had a similar problem where a coax tv cable passes through a pine tree. Eventually the insulation wore away and the tree touches the metal shielding in the cable. Howver, the pine tree was tall enough to occasionally brush against the local power supply lines. Not a problem on a dry day, but enought to give you a shock when it rained.

Question- Does your coax cable ALSO supply your interent service?

First, I'd go outside and look where the coax cable comes off the pole, does it pass through any trees that ALSO touch power lines?

Follow the cable tv coax cable into the house, looking for where the cable is grounded. You're looking to see if the coax cable is grounded to something that could be hot


Are there any OTHER devices connected to the TV? VCR, DVD/Blueray player?
Because if any of those are plugged in, then the various cords between the boxes could create a charge.
 
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Old 08-24-18, 02:51 PM
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I'm in an apartment building that was rewired in 2016. So, I can't dig into walls too much lol

My internet comes via coax cable to my modem.
My TV comes via coax cable to my shaw cable box.
Both come from the same source via a splitter. Those were installed like 2 weeks ago. All of that works no problem.

I have a TV that had a HDMI cable to my cable box and another to my roku.
I unplugged my roku HDMI cable, and plugged in this new 25ft HDMI cable. No problem.

When I plugged that cable into the HDMI port on my computer, it tripped. I have two HDMI ports on my computer, one on my video card, another on the mother board. Both trip the circuit.

So, I'm not following how my coax cable is involved in this scenario?
 
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Old 08-24-18, 04:29 PM
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If you don't understand then you will probably require the services of an electrician.

Your cable line is supposed to be 100% grounded. There should be NO voltage measured or present on the shield. Since you are only connecting two prong powered devices to the system..... you won't see any problem. Now.... you are trying to connect a computer that SHOULD be grounded thru the third pin on the power plug. If you connect two devices together that are grounded there will be absolutely no problem. That means you should be able to connect the GROUNDED computer to the GROUNDED (thru the cable line) TV.

However..... in your case..... one of the grounded devices is not grounded. It is LIVE. This is a deadly problem. I come across this routinely. Many times it can be from a short in the TV power supply to the metal frame. As others have mentioned..... the cable line which should be grounded is not and is picking up a live voltage from somewhere.

Without a voltmeter...... this can only be a never ending discussion.
A meter MUST be used to determine where the problem lies.
 
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Old 08-24-18, 06:09 PM
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Originally Posted by vanwalden
So, I'm not following how my coax cable is involved in this scenario?
I see 2 likely scenarios. First doesn't involve the coax. Second does.

#1 is that the outlet at the TV is reverse wired, i.e. the "hot" and "neutral" are swapped.
Your TV, Roku and cable box couldn't care less if they are plugged into an outlet that is reversed wired; they use ungrounded 2 prong plugs, (and IIRC those are unpolarized plugs)

In plain english, these devices convert ANY 120 V difference into DC power to run the device, they work equally well hooked up forwards or backwards. But, if you hook them up to something that is wired correctly, you blow a fuse.

#2 Is that the coax cable is not connected to ground. This lets a dangerous voltage build up in the TV equipment, but connecting the HDMI cable suddenly relieves the pressure and causes a high flow of current which trips the breaker to prevent damage to you and your TV equipment. .
A circuit breaker is the electrical equivalent of those gas station fuel line disconnects; they automatically shut off the connection if the flow rate is so hight that it indicates that something is wrong.
 

Last edited by Hal_S; 08-24-18 at 06:50 PM.
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Old 08-27-18, 05:59 PM
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Ok, I borrowed my buddies volt meter. I'm not sure how to use it properly. There are a ton of videos online but none seem to be about my issue? I tested the outlets, but how to do you test the actual tv or hdmi outlets or the coax cable?
 

Last edited by vanwalden; 08-27-18 at 06:30 PM.
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Old 08-27-18, 06:35 PM
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Using the AC volts setting just over 120vAC or auto AC. You need to check from any metal on the TV...... like the F connector or any jack location to a known ground.

A known ground is a cold water pipe, faucet, baseboard heat pipe, A/C-heat register, etc.
You could try checking from the TV to the round ground slot on a nearby receptacle or the plate screw.

Check receptacles too.
From the large slot to the small slot should be 120vAC.
From the large slot to the ground pin or plate screw should be 0v.
From the small slot to the ground pin or plate screw should be 120vAC.
 
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Old 08-27-18, 06:51 PM
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Ok, I tested the TV with the round ground slot as the ground. Checked every metal surface I could find, there was never any reading....what does that mean?
 
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Old 08-27-18, 07:46 PM
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I'm assuming the TV was plugged into the wall and the HDMI line to the cable box was attached.

Is your computer nearby ? Check carefully from that metal case to the TV. Don't touch the computer and Tv at the same time with your hands. Use the test probes.
 

Last edited by PJmax; 08-27-18 at 08:09 PM.
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Old 08-27-18, 08:42 PM
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The TV was plugged in, but not the HDMI cable. If I plug that to the TV and computer, I lose power. So, I couldn't test it with that plugged in...?

I will try from the metal case to the TV--so in that case the metal computer case is the ground? What's the difference between testing the TV from the outlet ground in that case?
 
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Old 08-27-18, 08:55 PM
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You need everything plugged in like you had it before the bang with the computer HDMI cable. You have to determine what is hot. The cable is connected to the cable box and the cable box is connected via the HDMI cable to the TV. That makes the TV connected to the cable line.

You can also check from the cable TV F connector to ground.

Did all the concerned receptacles check out like I outlined ?
 
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Old 08-28-18, 08:38 AM
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The first thing I'd do is set everything up the way it was, but don't plug in the HDMI.

Check
From the metal end of the HDMI cable to the TV HDMI in. It should be 0v AC, (but probably isn't)

After that, you want to get a cheat sheet

TV outlet
From the large slot to the small slot should be 120vAC.
From the large slot to the ground pin or plate screw should be 0v.
From the small slot to the ground pin or plate screw should be 120vAC.

HDMI to TV outlet
From the metal end of the HDMI cable to the round plug. Should be 0v
From the metal end of the HDMI cable to the large slot. Should be 0v
From the metal end of the HDMI cable to the small slot. Should be 120v

Cable Box
Unscrew the Coax cable from the cable box and check

HDMI to Coax
From the metal end of the HDMI cable to the center coax wire. Should be 0v
From the metal end of the HDMI cable to the coax metal nut. Should be 0v
From the center coax wire to the coax metal nut. Should be 0v AC

TV outlet to Coax
From the coax metal nut to the round plug. Should be 0v
From the coax metal nut to the large slot. Should be 0v
From the coax metal nut to the small slot. Should be 120v



Computer outlet
From the large slot to the small slot should be 120vAC.
From the large slot to the ground pin or plate screw should be 0v.
From the small slot to the ground pin or plate screw should be 120vAC.

Unscrew the coax cable from the modem and check the voltages-

Modem Coax
From the center coax wire to the coax metal nut. Should be 0v AC

Modem coax to Computer
From the coax metal nut to the computer case. Should be 0v AV

Modem coax to Computer plug
From the coax metal nut to the round plug Should be 0v
From the coax metal nut to the large slot. Should be 0v
From the coax metal nut to the small slot. Should be 120v
 

Last edited by Hal_S; 08-28-18 at 09:07 AM.
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Old 09-04-18, 09:41 PM
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Ok I tested the coax connections on my shaw cable box and it registers 10v. So unplugged from the TV and the coax unplugged, just the coax connection on the back of the box. That's not good is it.

I've got shaw coming to look at the box next week---anything else I could do?
 
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Old 09-04-18, 10:30 PM
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Where did you have the two probes when you measured 10v ?
That would not be enough to cause the breaker to trip.
Was this the cable TV wire to ground test ?

Unfortunately most cable installers will not understand your problem. You can try to explain to him what happens when you connect the computer to the TV. If he has a meter he may know how to use it to test here.
 
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Old 09-04-18, 10:48 PM
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It was from the cable box coax to ground.
 
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Old 09-05-18, 01:52 PM
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Ok we know who has way too much time on their hands lol, but I thought a little picture might help and it keeps me out of trouble (for a little while). But only helpful if itís correct. Not sure it is.

So unplugged from the TV and the coax unplugged, just the coax connection on the back of the box.
Sounds like you just checked a connector on the cable box not the actual cable coming into the box (i.e., not cable end 4). Is that the right thing to do? Maybe I misunderstand.

But anyway, the 10v you mentioned rang a bell. I remember a post somewhere where a guy was seeing 10v on his Comcast cable. A Comcast tech online told him that when he switched to digital(I think he said digital ) they should have removed a shunt from a tap and they probably didnít. So he told the guy to call Comcast and they would take care of it for free.

He said something like the shunt added 10v for some legitimate purpose ( I canít remember what) but after the conversion to digital it wasnít needed and it should have been removed. Iím pretty sure he said conversion to digital but not 100% sure.

Anyway maybe that 10v shunt is a kind of a standard thing in cable and would explain the 10v you are seeing, especially since you just had an installation in the last few weeks. Just a thought.

But as PJmax says that 10v wouldnít trip the breaker.
 
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Old 09-16-18, 05:59 AM
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Good picture - I've done a quick edit to highlight ground to coax versus ground to ground wire.
Do you see the potential ground-loop between #1 and #15 created by connecting the HDMI?

Modems usually have ungrounded DC-in power, BUT Ethernet doesn't t have a ground wire, so Modem is grounded to #1 as well.
Most Cable Box, TV, and Roku/DVR use ungrounded 2 prong plugs, they are not grounded to #18,
their "grounding" would be back through HDMI and coax to #1.

Computers DO have a grounded polarized plug, grounded at #15.
If the coax has a bad ground (they usually do) then connecting the HDMI to the Computer provides a new grounding route for Modem, Cable Box, and TV. If there's a loose neutral in the outlet, or a reverse wired outlet, the HDMI cable becomes the preferred ground current/return current route.
 

Last edited by Hal_S; 09-16-18 at 06:56 AM.
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Old 09-16-18, 10:54 AM
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Good explanation. Wish vanwalden would come back here and tell us what happened. It's like not hearing the end of a good mystery story . Keeps you hanging - lol!
 
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Old 09-16-18, 10:59 AM
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The coax is connected to the cable box. The cable box is connected to the TV with an HDMI cable. That would put the cable shield and the TV chassis at the same potential. If the cable was grounded like it should be..... then the TV chassis would also be grounded. If the cable was not grounded..... then it and the TV chassis could become live.

Since connecting a desktop computer plugged into the wall with a three prong plug would ground the computer case... an HDMI cable connected to the computer should be grounded. When that grounded cable was connected to the TV there was a short.

The biggest problem in a situation like this is...... you need to make voltage measurements to a KNOWN good ground. Something in this system has voltage on it that it shouldn't.
 
  #26  
Old 09-16-18, 05:08 PM
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Originally Posted by PJmax
Something in this system has voltage on it that it shouldn't.
Or some current is looking for a better route.

I think anyone who's done DIY electric work remembers their first (and hopefully- last)
time taking a shortcut and working on a lightfixture that was "TURNED OFF" but getting a tingle from the neutral wire that was "hot" because it was carrying current from something else on the circuit that was still turned on.

Example, somebody in our office fried a Laptop when their papershredder jammed. Although Laptop was plugged into one outlet, and Shredder was plugged into different outlet, their Printer was plugged into the same outlet as Shredder and the Printer was connected to the Laptop by a cable.
Shredder jammed, motor stopped, voltage dropped, current spiked. Current flowed through the outlet ->cable-> outlet and actually melted the cord and fried the laptop.

It's not the voltage that kills electronics, it's the amps.
 

Last edited by Hal_S; 09-16-18 at 06:57 PM.
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