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Bizarre Home Electrical Problem (Pic Heavy)

Sigurthr

Sigurthr

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MarioMaster said:
I have never heard the theory on incandescent bulbs causing floating grounds. This makes no sense to me and I'd like to hear their reasoning on how this happens.
Click to expand...

Let me just clarify here... it is NOT MY THEORY. That is what I was told by the licensed electrician I called to my house to find out why when turning off a breaker and there being 0V between Hot and Ground I still got shocked when touching Neutral and Ground. He said:
Licensed Electrician said:
"it is because of the lighting circuits, sometimes when lighting circuits are tied in with outlets they pass on an ac signal between neutral and ground. It is very dangerous and causes a lot of injuries and deaths every year. It can't be fixed in your case because I would have to gut your walls and remove all the existing wiring and rewire the house. Just hit your mains breaker and work by flashlight when you have to change an outlet from now on."
Click to expand...

Let me also add that inside the electrical box the neutral buss is bonded to the ground buss and the ground buss is bonded both to the water pipes and to an additional 8ft ground rod I installed. All the grounds are continuous throughout the house, but not all of the house has grounded outlets (2 prong).
 
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MarioMaster

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Yeah I know, I was just saying that it made no sense to me. Lightbulbs are a resistive load and should have the least effect on electrical circuits.
 
Sigurthr

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Aye, I have no idea. The fillament's reactance (inductive) at that frequency should be negligible considering the hundreds of feet of wiring lol. I suppose if the neutral line was discontinuous and nonlinearly connected to adjoining circuits... but then how would you get current flow at all... I don't know.
 
n2stuff

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As you guys know a light bulb is a dead short. Also any lighted wall switch uses this to illuminate its indicator lamp. It does sound like it's the power supply.
 
T

Things

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Lightbulbs aren't dead shorts, they still have a few ohms or resistance. For example, a 60W 240V light bulb should measure around 960 ohms once fully heated. Inrush can be a fair bit more.
 
n2stuff

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Things said:
Lightbulbs aren't dead shorts, they still have a few ohms or resistance. For example, a 60W 240V light bulb should measure around 960 ohms once fully heated. Inrush can be a fair bit more.
Click to expand...

True. But to a digtal meter that doesn't put the circuit under a load it will look like one.
 
Cyparagon

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I saw this and thought of you:

5RzaP.jpg
 
Tech_Junkie

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I had a simular problem, but very low shock, and a hum in the audio equipment (stereo, TV. and PC). I find out the I had everything connected in one way or another, but had some plugged into the other room because of limited outlets. This cause a small bridge somehow between the 2 mains coming in the house.

Could it be possible that you have a simular situation?
 
Hemlock_Mike

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Could the pole transformer have a bad neutral connection to ground?
This could cause a lack of balance between L1 & L2.
Like they say, Check your Neutral to ground (pipe) voltage. This looks like bad news
to you and equipment. Add a ground if needed.
HMike
 
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n2stuff

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Hemlock_Mike said:
Could the pole transformer have a bad neutral connection to ground?
This could cause a lack of balance between L1 & L2.
HMike
Click to expand...

That is a very bad problem. I have had customers with that and it does some wierd things. You will see lights getting brighter in one part of the house and dimmer in others. Without a ground/neutral A & B phase don't have a reference to earth and they float. I have seen a voltage difference from 50 to 170 volts on a outlet. I do still think the power supply is at fault.
 
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Seoul_lasers

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Hey... this is a common issue in korea as well, except for the fact we are 220/240V
and 110-115Vac between hot and ground.
I got a **very nasty shock** off the back end of a computer case in a school because the ground was floating. Lack of electrical safety here is incredible in older buildings!!
I'd check the ground on your socket with your DVM and see if you actually have a ground there. After you determine OK for ground, ground the case of your PSU.
I've had the same issue with an older car battery charger in Canada before giving a stinging 60v shock. I just wired the case to ground... shocks no more.
 
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Fiddy

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In Australia we have a MEN link that bonds the neutral to earth.
 
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