So, a friend told me today of his weekend experience. Apparently the renters in the bottom part of the house blew the dryer breaker. When the landlord came over to check, he noticed there were more breakers that had popped. So he reset them all, and again when the dryer started, not long after, its breaker popped again. Shortly after this, as I understand, my friend noticed a burning smell in his part of the house, upstairs, and soon discovered that the power bar where he had his smart TV hooked up to burned! I saw the picture, there was a black streak on the wall where it's mounted (the power bar) and a big, 1 inch hole in the back of it. His guess was that the MOV or whatever protection device did its job, but seriously, the thing could have practically caught on fire...
Does anyone have an idea if this is a surge of some kind? There was no lightning or bad weather when this happened...
Does anyone have an idea if this is a surge of some kind? There was no lightning or bad weather when this happened...
I would like to agree with the theory of the power bar, but the synchronicity between the two events was more than coincidental, I think... That chinese power bar did save his tv... Gosh, I'll have to ask him for the picture. He's gonna have to repaint that part of the wall, it's nasty
If the ground wiring is a problem, and a cause of the issue, then it's the landlord's responsibility to repaint and fix the electrical.
The landlord is apparently going to get an electrician in. But gosh, I wouldn't want to be in his shoes now. Unless I'd be the house owner, and could debug the problem with my knowledge...
In a USA type AC power system with 120/120V and 240 Volt. A lost Neutral can cause that type of problem. The lost Neutral or more likely a high resistance Neutral can cause the 120V legs to divide the 240V unevenly. With say one leg at 80V and the other at 160V.
My thinking, and my money, is on what Speedskater said.
A lost neutral will not pop a 240 volt breaker given a 240 volt load with a starting cap/centrifugal switch combo. However, a lost neutral will cause quite a few breakers to pop due to higher voltage, exactly what speedy stated.
The power bar hopefully saved the TV and anything attached...by throwing itself on the grenade.
The real question is where it is disconnected. In the two cases I have witnessed, it was the messenger wire (neutral steel wire) that broke supporting the two hots from the pole to the house. If between the pole and the house, it is the electric company's responsibility. If in the house, the landlord.
For safety, have the electrician also examine the bonding from the panel to the water main entering the house, and the run to the grounding electrode. The water main connection (historically speaking) has been a the safety net for plumbers for a century now, but is subjected to a compromising environment in the basement typically.
The OP doesn't detail where he lives...east coast has a one bushing power delivery system, west coast uses two....so grounding is a tad different.
The powerbar did it's thing. I am not happy it burned the sheetrock behind it, but it could have been worse. I must admit, the Monster powerbars I inherited from my mom were massive metal things that would not have had a hull breach, so something could be said for that.
John
A lost neutral will not pop a 240 volt breaker given a 240 volt load with a starting cap/centrifugal switch combo. However, a lost neutral will cause quite a few breakers to pop due to higher voltage, exactly what speedy stated.
The power bar hopefully saved the TV and anything attached...by throwing itself on the grenade.
The real question is where it is disconnected. In the two cases I have witnessed, it was the messenger wire (neutral steel wire) that broke supporting the two hots from the pole to the house. If between the pole and the house, it is the electric company's responsibility. If in the house, the landlord.
For safety, have the electrician also examine the bonding from the panel to the water main entering the house, and the run to the grounding electrode. The water main connection (historically speaking) has been a the safety net for plumbers for a century now, but is subjected to a compromising environment in the basement typically.
The OP doesn't detail where he lives...east coast has a one bushing power delivery system, west coast uses two....so grounding is a tad different.
The powerbar did it's thing. I am not happy it burned the sheetrock behind it, but it could have been worse. I must admit, the Monster powerbars I inherited from my mom were massive metal things that would not have had a hull breach, so something could be said for that.
John
Here is the only power strip I use unattended:
https://www.amazon.com/dp/B000BVC0WO
All steel all around (I have others with plastic backs). Some surge protection (mostly to evade NFPA technicalities). Usually OK build quality. While it looks like standard duplex outlets they are actually custom-- you can rebuild the case with better receptacles. I had six in my old workshop, two in this house, no trouble.
I use this on the back of my rack: https://secure.sayal.com/STORE2/View_SHOP.php?SKU=250296
And one of these for the computer/desk, another under the television: https://secure.sayal.com/STORE2/View_SHOP.php?SKU=223146
I have one that's diamond plate under the shop desk: https://www.lowes.ca/product/power-...p-power-strip-built-in-circuit-breaker-223771
And a couple of these by the shop desk, too: https://www.canadiantire.ca/en/pdp/mastercraft-8-outlet-contractor-power-bar-0527261p.html
The last one is the only one I've had to fix. The neutral fell off inside. I soldered it properly and it's been fine since.
You would think with 74 "outlets" in a 12x18 foot room, there'd be more than enough places to plug in, but nope.
OH I almost forgot I have a 6 outlet one I found in the garbage and fixed by bypassing the surge/breaker.
That makes 80...
I've never has a melt or fire with any of them. Am I lucky? No. I just don't plug a space heater or air conditioner into a power bar 🙂 I use contractor grade #12 for that.
And one of these for the computer/desk, another under the television: https://secure.sayal.com/STORE2/View_SHOP.php?SKU=223146
I have one that's diamond plate under the shop desk: https://www.lowes.ca/product/power-...p-power-strip-built-in-circuit-breaker-223771
And a couple of these by the shop desk, too: https://www.canadiantire.ca/en/pdp/mastercraft-8-outlet-contractor-power-bar-0527261p.html
The last one is the only one I've had to fix. The neutral fell off inside. I soldered it properly and it's been fine since.
You would think with 74 "outlets" in a 12x18 foot room, there'd be more than enough places to plug in, but nope.
OH I almost forgot I have a 6 outlet one I found in the garbage and fixed by bypassing the surge/breaker.
That makes 80...
I've never has a melt or fire with any of them. Am I lucky? No. I just don't plug a space heater or air conditioner into a power bar 🙂 I use contractor grade #12 for that.
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It is all in the numbers and in the cheap section there are cheaper ones and cheapest ones. I used to work in a branch were many Schuko power strips were used. Schuko on itself is well designed.
These power strips were sold by the company I worked for and these were high quality industrial versions. However some customers had chosen to use consumer grade power strips. I have witnessed various times that these had the plastic casing turning brittle/cracking and/or contacts to loose spring force leading to bad contacts and burn marks. Also these often have power switches that are simply unreliable. After a few times being alarmed by customers and/or fire monitoring systems we decided to ban all consumer grade power strips.
We realized that these were a liability. There is no substitute for quality. How such unreliable stuff passes tests I don't know.
After having witnessed a few cases of fires (or near fires) all I can say is that switching off power strips after use/at night is simply a wise choice.
These power strips were sold by the company I worked for and these were high quality industrial versions. However some customers had chosen to use consumer grade power strips. I have witnessed various times that these had the plastic casing turning brittle/cracking and/or contacts to loose spring force leading to bad contacts and burn marks. Also these often have power switches that are simply unreliable. After a few times being alarmed by customers and/or fire monitoring systems we decided to ban all consumer grade power strips.
We realized that these were a liability. There is no substitute for quality. How such unreliable stuff passes tests I don't know.
After having witnessed a few cases of fires (or near fires) all I can say is that switching off power strips after use/at night is simply a wise choice.
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It’s not the MOV’s “job” to deal with sustained overvoltage. They are intended to deal with short term events. Even a 6000 joule one, the biggest they make in that form factor, would have eventually caught fire.
Hopefully the open neutral is some place where they can get to it to fix it. If it’s on the pole you will have a hell of a time convincing anyone that there is even anything wrong, let alone take responsibility. I lived with one for years and the only solution was to install a 10kVA pad mounted trafo and run a sub panel for all the critical 120V stuff off of it. Until the neighbors house nearly burnt down,then. TECO finally took the repeated complaints seriously.
Hopefully the open neutral is some place where they can get to it to fix it. If it’s on the pole you will have a hell of a time convincing anyone that there is even anything wrong, let alone take responsibility. I lived with one for years and the only solution was to install a 10kVA pad mounted trafo and run a sub panel for all the critical 120V stuff off of it. Until the neighbors house nearly burnt down,then. TECO finally took the repeated complaints seriously.
Just wanted to thank you guys for your input! There's loads (pun intended) of good info here, which I will pass on to my friend.
Watch out for power strips with unfused MOVs in them, I've seen them on a couple of occasions and they can be really dangerous. A varistor tends to fail short circuit, so it should always be connected through a fuse or circuit breaker to the ciruit it protects. For a short duration voltage spike, the fuse will hold long enough for the MOV to do its job. When the MOV fails due to the energy absorbed, it shorts out and the fuse blows.
To wg_ski and jneutron, regarding the neutral between the pole and the house, this is what concerns me. How can you even determine this easily? You'd have to check for continuity between two points that are at least 20 meters apart! I know it can be done, but having Hydro whatever test that for something that isn't yet a problem seems like it'll never happen...
He said their washing machine was the one tripping the breaker... So, not 240V. Either way, it's a serious thing when the power bar self-destructs like it did... He lives east of Winchester, to be more specific.
He said their washing machine was the one tripping the breaker... So, not 240V. Either way, it's a serious thing when the power bar self-destructs like it did... He lives east of Winchester, to be more specific.
At the place where I work, we had a problem somehow with on overvoltage on the mains. - who knows how? At the time, the computers were using power supplies with switchable input range (doubler or FWB for 115/230). My computer was plugged into an outlet strip with MOV - the MOV took the hit and blew the breaker on the strip, so my computer survived the surge. One of my colleagues had his computer plugged directly into the wall, so he wasn't so lucky - his power supply got lunched. All I had to do was replace the outlet strip.
I was getting my folks' house ready for sale in 2021.
So I stayed in the empty house a bunch of times during the first half of the year.
I noticed that when I took a shower in the master bathroom, occasionally I would get a nice hard tickle if I touched the
hot or cold spigots. I brought my DVM with me on one of these visits, and found that with the water off, there was no voltage measured between either
spigot and earth ground. But if the water was RUNNING, 80 Volts AC appeared on the spigots!
I called in a local electrician, who informed me that the neutral line was not connected, but he could
not find anything wrong in the house wiring. He advised I call the electric company to troubleshoot.
Well, the guy who came out to the house found that the neutral line was disconnected under the street somewhere.
Couple of hours later, it was fixed.
I had another friend years ago who had a lightning strike hit near his house.
It took out every electrical appliance in the house! TV, refrigerator, everything.
The electric company came out to take a look, and found that the neutral line was not connected, and probably had not been connected for years.
So I stayed in the empty house a bunch of times during the first half of the year.
I noticed that when I took a shower in the master bathroom, occasionally I would get a nice hard tickle if I touched the
hot or cold spigots. I brought my DVM with me on one of these visits, and found that with the water off, there was no voltage measured between either
spigot and earth ground. But if the water was RUNNING, 80 Volts AC appeared on the spigots!
I called in a local electrician, who informed me that the neutral line was not connected, but he could
not find anything wrong in the house wiring. He advised I call the electric company to troubleshoot.
Well, the guy who came out to the house found that the neutral line was disconnected under the street somewhere.
Couple of hours later, it was fixed.
I had another friend years ago who had a lightning strike hit near his house.
It took out every electrical appliance in the house! TV, refrigerator, everything.
The electric company came out to take a look, and found that the neutral line was not connected, and probably had not been connected for years.