Weird open ground issue?

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  #1  
Old 06-15-15, 04:49 PM
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Weird open ground issue?

Hi so I have an outlet in my room with an open ground, my tester says open ground and the light on my power strip that says grounded is not on. I have various things plugged into this power strip my computer, router, monitor, HDTV, etc. (i know an open ground is bad but i dont have much of a choice i will try to fix it soon)

So the weird thing is that when i plug in my HDMI cord from my computer to my HDTV the grounded light comes on and my tester also reads that the whole power strip is grounded from me plugging in my tv's HDMI cord, if i unplug it the light on the power strip goes off and the tester says it's not grounded. This absolutely baffled me i have scoured the internet to no avail. Anybody have any ideas?
 
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  #2  
Old 06-15-15, 05:11 PM
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I assume your TV is plugged into a different outlet (not the power strip?). The shield in the HDMI cable is connecting the ground of the TV to the ground of the computer...it's like a wire tying the two grounds together and substituting for the missing ground connection on the one outlet.

But fix that outlet!
 
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Old 06-15-15, 05:57 PM
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Remove the power to the receptacle, pull it from the wall and see if the grounding wire is attached? Do you have metal boxes or conduit, or is it NM cabling? If that receptacle is grounded, you'll have to back check every receptacle on that circuit until you find it. Often I have found broken grounding wires in porcelain light fixtures. Electricians choose to clip the wires or not bother to twist them (if pass through), making the ground open.
 
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Old 06-15-15, 06:20 PM
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Yes the TV is plugged into a different outlet but that outlet also has no ground. I will check if the grounding wire is attached when i get home tomorrow and get back to you. Its just one room in the house that has an open ground on the two outlets inside of it.
 
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Old 06-15-15, 08:38 PM
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Your TV is picking up a ground from the cable company and when you connect the TV using the HDMI cable that is extending the ground.

Everything will show ok but you'll still want to find the problem as drawing a system ground thru the HDMI cable is not good.
 
  #6  
Old 06-16-15, 08:34 AM
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Okay well bad news, there is no grounding wire going to the three prong outlets in my room (which really pisses me off) I do not even remotely have enough money to call in an electrician and get my house re wired. I have read that a GCFI outlet is better than nothing would it be worth putting in gcfi outlets on the ungrouned outlets?
 
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Old 06-16-15, 08:46 AM
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It is better for safety, but will not improve the the surge protection or the function of electronics that require a ground to operate correctly. You only need one GFCI receptacle per ungrounded circuit, provided it is installed as the first device on the circuit with LINE and LOAD terminals connected correctly. Code allows installation of a retrofit ground wire without a full re-wire of the circuit, but is impractical unless you have access to a basement/crawl below or attic above the room.
 
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Old 06-16-15, 08:51 AM
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Putting GFCIs in would at least improve the safety of having ungrounded outlets since they shut of current flow if you are about to be shocked. So it's worth doing for that. But they don't provide a ground connection to the equipment. That can cause various issues like electrical noise and interference, and things like surge protectors that require a ground to work will be ineffective. So eventually you should address this.

Did you have the home inspected? This should have been caught. If it's only this room, it seems a bit unlikely that your whole house is wired without grounds.
 
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Old 06-16-15, 09:01 AM
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Did you have the home inspected? This should have been caught. If it's only this room, it seems a bit unlikely that your whole house is wired without grounds.
That depends on the age of the home. It was normal in the 60s (and earlier) for houses to be wired without a EGC in the 120 volt branch circuits.
 
  #10  
Old 06-16-15, 09:39 AM
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At first i thought it was just my room that was ungrounded, but i checked all the outlets in the house and they are all ungrounded, besides the outlets in the kitchen they are grounded.

I did read that an ungrounded outlet can "chrage" my computer case if something were to go wrong and kill me if i touched it. So hopefully the GCFI will protect against that.

The only equipment i am worried about is my computer, i built it myself and its not cheap. The power supply in it is very good and has excellent voltage regulation and every safety and protection feature they can put in a consumer computer power supply. But im not sure thats enough.

Do you guys know anything about UPS (uninterruptible power supply) they look like big power strips with battery backups and are supposed to protect against voltage spikes. Might consider getting one of those for the computer.

I can probably get an electrician in here at some point but like i said money is seriously low at the moment.
 
  #11  
Old 06-16-15, 12:13 PM
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It's not really that the ungrounded outlet will charge the computer case, but if the computer (or any other appliance with a metal case) was to have an electrical fault inside which allowed an energized wire to touch the metal case, the metal case will then also become charged. In a grounded circuit, the ground wire will clear that charge safely and cause the circuit breaker to trip. In an ungrounded circuit, your body could clear the charge instead by shocking you. If there is a GFCI protector on the circuit, that will prevent you from being shocked in that situation by very rapidly disconnecting power when shock conditions develop.

There are a variety of types of UPS, from simple power strip and battery with no power conditioning up to full online converting power conditioners with advanced capabilities. In either case however the surge protection features cannot work without a good ground. The other features may not work or may not work well without a good ground.
 
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Old 06-16-15, 12:23 PM
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True, but they weren't wired with 3 prong outlets. That's what should have been caught in an inspection...3 prong outlets with no grounds. It's a safety issue and a code violation to have 3 prong outlets without grounds, unless they are GFCIs, or supplied by GFCIs, in which case they should be labeled NO EGC.
 
  #13  
Old 06-16-15, 02:15 PM
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Ok thanks for all the help guys. I think i will put in GFCIs on the ungrounded circuits and label them for the time being, hell maybe i will even run an extension cord from a grounded outlet in my kitchen to my computer so at least that can have a ground. Then call an electrician when i have the money.

Any idea why I have 3 prong outlets with no ground? Lazy electrician maybe? The house is pretty old so im assuming it was built when we didn't use grounds on every outlet and then somebody came in and replaced the two prong outlets with three prong but didn't hook up a ground? I dont see the point in that.
 
  #14  
Old 06-16-15, 02:19 PM
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Previous homeowner wanted different color receptacles or wanted to avoid the hassle of using 2 prong adapters, and was ignorant of the safety problem they were creating by replacing two prong receptacles with three prong.

Grounds were not routinely included in branch circuits until about the 1960s. Houses built prior to that likely do not have ground wires assuming they still have original wiring.
 
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