True or false?
link (Original hebrew article) .

And what from that?
Improperly maintained electrical systems causing home fires? Happen way too often, it is the major cause of home fires...
So periodic qualified checks are quite vital to prevent most of them. Because the major problems make their signature way before the disaster breaks out, so could be rectified way in time.

Aged circuit breaker not switching OFF when it should? I've not heard about real problem of this kind here, but when remember opening a few of them, I have seen a few scenarios to fail in this way. But there is no safe test capable to detect this problem approaching, so an advice to replace the breaker as a matter of prevention may work.  But more often they fail in the way, than they trip at lower than rated current. Well, that may "inspire" someone to bypass it and then the fire is nearly unavoidable.
What should not be underestimated is the self-overheating, when inn er springs loose their force and so contact get more resistive.
Other source of fire may be a dust accumulated in the arc quenching chamber. Not only the resulting flame just prevent the arc being quenched in time, it could ignite all the dust around...

Generally dust contaminating the electrical devices in the breaker box: If an arc seep out of the breaker, it could ignite this dust, with quite quick disaster as a consequence...

Fires from loose screws? Very common, mainly in installations using aluminum wires. One of the causes I do fear a lot, because there is no protection device on the market capable to detect it and disconnect the faulty circuit in time. In the US the AFCI's of the second generation's should be able to do that, but I've seen no such device offered for 230V/50Hz.

Quite "popular" are fires officially blamed on Christmas tree lighting.  Well, I doubt it really happened as often, if at all (I more suspect the sparklers igniting the decorations, but as there is usually nothing remaining from the tree and the sparkler would cause no money from the insurance company, the lights are blamed). But what happen if one bulb fail? It's bypass device activate, short it out, so the rest could still work. But there is one lamp less in the chain. If that would be kept ON for long time, another lamp burn, increasing the voltage for the rest further. So a chain reaction could be started. But how it stop? Could it really short out the mains?

Addressing the article points :

Whats right :

Bad circuit breakers - Seen those. Its not much about their age, but some are simply made too bad - they were unreliable to the same extent when they were new. My friend had a breaker that did not trip once after a short circuit (tripped the main but not the branch). I did not like it. Plugged in a test lamp, flipped the breaker off, but it did not feel right (like the handle is doing nothing). lamp still on. Hit the side of the breaker with the screwdriver, then there was a click in it and the lamp went off

Bad RCD (GFCI's) - seen this too. But their claim for "limited life" of the breaker is debatable - Its pretty simple lectromechanic device, and as such supposed to last forever. In all 30+ year old RCD's from reputable manufacturers i seen, when i pressed Test they tripped. Some cheaper RCDs did not trip even though they are not that old. OTher thing, i seen such cheap RCD's fail with arcing switch (internal) contacts (and melted enclosure) which menas that they mighthave started a fire in their own right rather than protecting from a fire

(RCD's are meant for protection in case of electric shork and not for fire prevention, but in fact they do prevent some fires by tripping in
"stray curent" cases where the small leakage current can go through pretty dangerous path ie wet drywall etc)

Load on the system - well he is right. There are many issues, see below

Now what i call BS :

"The electric blanket" is listed along with heating appliances as a "heavy appliance" - Hey eletrician, go and look before you write. Most of them are less than 100W powre consumption. Yes, the blanket can be dangerous in its own ways but as a cause of overload

"The surge protector regulates the current going to the appliance" - Hey electrician, did you open one ? Its just 3 MOV's between L/N/E. It does not "regulate the current". If anything, it is only ANOTHER fire starter when you have open neutral - most surge protectors sold here are just MOV's no thermal protection, and they are rated at like 275-375V. Perfect for that bad neutral incidents

And what could be better :

"arcing sockets" - Basicaly he is right, but i vcan imagine that some folks will be eating video when they see that their laptop PSU is making a spark every time it is plugged in. Would be good idea to say that sparks are to be expected with stuff like this and it is normal. But look further. "Noises coming from power strips (transformers)". Hey electrician, power strips are NOT transformers

"power strips" - Basically he is right, but worth mentiomning that power strips rated to 16A usually begin smoking at about 10A. Thats rihgt, our standards institute is busy with efficiency ratings of lamps instead of sotring out the consequences of that "16A mistake" from the 80s




And if i would write it i'd address this :

Heating appliances : Keep clearance in front of them. dont put them to dry stuff except radiators and A/C. The IR heaters and the heat fans have magic powers like IR and hot air. Stuff subjected to those things gets WAY hotter than you might think, especially the IR. You might think it is ok to put some clothes at 1m from th heater (cmon, its 1m, far enough), next thing they are on fire. Also dont use them on carpet. They can be tipped face down and thats it

Sockets : They can be loose, especially old ones. If you insert hte plug and dont feel that it goes tightly into the contacts, it means that it cannot hold much load. Ok for a cell phone charger, bad for a lamp, unacceptable for bigger electronics and any big appliances

Splitters and cables : They can be bad, loose, too thin. Open hte plugs and sockets and inspect that every screw is tihgtened well, isolation is complete etc. Dont load anything above 10A. Dont load switched power strips above 8A. I know its written 16A on them but trust me on this one

Mess behind the computer : All too often i see a stack of splitters and adapters in htere, which is so big that it is mechanically unstable. Dont let it be. Replace all that splitters to one or more power strips. The ampacity is unchanged ut nw you can be sure that all plugs are tightly inserted in the sockets. And dont let htat corner be dirty

Wiring in old homes : It is usually done with 1.5mm^2 in branches, yet most breakers are 16A. Check out which rooms each branch covers (its usually like this in old flats : living room+1 bedroom, bathroom+other bedroom, washing machine, water heater, kitchen).Dont load any such GROUP at above 12A continuous for 1.5mm^2 wiring

Wiring in old homes : Often badly comnnected. Especially common with wire nuts - They were used here untill hte 70s (and few contractors used up the stock even in the 80s), yet looks like NOBODY knew how to use them properly, so its common to find several glowing connections in every flat wired with 1.5 and wire nuts. Go and find out

Upgrades : Often bathroom permanent devices like heaters and electric showers are wired to existing wiring. Now thats BAD. Electric shower takes over 20A which should go on 4mm^2 (not even 2.5), but i seen electricians who tap it from the 1.5 wiring that used to be for the water tank (whose idea it was to use 1.5 for hte tank in the 1st place ). I even seen some that tapped it from the light fixture!!!! (1.5 too) Anyway it can survive like that, mostly due to the fact that current is drawn briefly. But what, you open the ater for a bit longer and get a fire ?

Bypassing the main breaker : If you are in an old flat in Israel just try this : Flip off the main breaker, and try to switch on the shower, the water heater, the A/C. The older the flat is, the higher chance that one of them will work with the main breaker off. And here is why : The main breaker in old flats is usually 25A. The shower alone takes 20+A. Few lights around the home 1-2A. Electronics 2-3A. Room heater 10A. Together 33-35A. Now look at the trip curve for "C" breakers - That'd trip exactly few minutes into the shower, when you are all over in soap. The user complained to the electrician. Now the correct thing to do is to order service upgrade from the electric company, which is expensive. What cheap electrician does is move the shower to take its power from before the main - so that the shower is on is own breakre and thats it. Nevermind the hack is usually done with 2.5's..

Besides, electric shower powered from before the main means that there is no RCD protection to it. So if there is 240 in the shower head the RCD is nowhere to protect you



Medved :

Breakers not wswitching off - sen that actually happen to my friend

Dust in panel devices - seen it hasppen the other way - building debris gets into the contacts preventing them from closing well, and the switch is heating and arcing as it is used. But what yoiu say is possible too, esp. if the dust is really dust and not small concrete debris which is largely unflammable (which was the case in the incident i seen)

Loose screws - Common in copper too, since electricians dont tighten the screws in the first place (or worse, using wire nuts without hte slightest idea how to install them correctly), or use inappropriae wiring (using stranded wire without crimped ends to carry 25A to circuit breaker ? Really ?)

Xmas tree - I think it is supposed to let enough of a short current to trip the 16A breaker. But some chains use really scary thin wiring and bad connections, that may have just enough resistance to limit the current a bit.... And if it limit enough to prevent immediate tripping of the breaker then there can be fire

I think the "transformers" instead of splitters, "surge protector regulate the current" and similar came from the Google (it is apparently some hebrew article translated by the Google without any correction), I don't expect Google to make the correct translation...

For the limited life of protection devices: RCD's have the "test" button (it inject a "fault" current, so the normal functionality is expected to respond and shut down), so they are quite easy to test. But overcurrent only circuit breakers do not have anything to test the complete system, while their mechanics could degrade too. There the only defense is to use known good brand products and really replace them in time.
Testing them by actually creating an overcurrent would for sure verify the breaker, but it would load the wiring and that could already be a source of fire - so it is an unsafe method...

The electric blankets may be of rather low current, but they are notoriously known to overheat by itself and cause quite serious fires. The problem is, they are usually rather large sheets, but they have thermal sensors only in some places. Now when the blanket become only covered in the area where is no sensor, that area could easily overheat and ignite the fire. And as pillows and blankets are involved, the fire have quite good material to eat...
There is no technical means to avoid this problem, so the only safety guard here is the user awareness of the problem. Well, I better heat up a l;iter of hot water in the kettle, pour it into the rubber hot water bottle and heat myself by this bottle. No electricity invoolved, the temperature can not be over 100degC (what already tell me there is something wrong), but it can never ignite a fire (I usually do not have any Nitroglycerin at home, nor anything similar, what could ignite from the hot water...)

Christmass tree: I really do not believe the tree illumination is the cause of the fire. As I wrote, the most likely scenario in my eyes is careless manioulation with sparklers and other open flames.
It become quite common, than when the real source of the fire could not be determined (because there is e.g. nothing left to give the clue), fire investigator usually write into the report "electrical fault" as the fire cause. And if the tree just burned down (taking some curtains with it), what evidence do you have to determine the real cause?

No Google. I read the original article as is, not the Google translation. Its all th there

The article tells about aging of RCDs, Not  word about aging of breakers

Blankets as i know them dont have sensors, they rely on limited power (through their predefined resistance) to limit the heat dissipation, to reach the wanted temperature under the expected thermal isolation conditions. There are many ways to make a fire with a blanket, none of them is overloading the home wiring with it.. Yet hte article ONLY says about overloading the wiring with blankets

Xmas tree : Can be verified if filaments in lamps are intact or not even after the fire. Many blown filaments = tree canbe thought of as hte cause. Intact filaments = look for something else. But cant a very bad string (with very thin wiring and some bad connections) reach ~12 ohm when all lamps shunt out ? If yes, there you have ~20A on the string wires, more than enough for a quick ignition but would take too long time to trip the C16 breaker

"The surge protector regulates the current going to the appliance" - Hey electrician, did you open one ? Its just 3 MOV's between L/N/E. It does not "regulate the current". If anything, it is only ANOTHER fire starter when you have open neutral - most surge protectors sold here are just MOV's no thermal protection, and they are rated at like 275-375V. Perfect for that bad neutral incidents

So this means that I need to disconnect my Supco GPT SC9L surge protector, which my UPS is connected to (To increase the weak surge protection of my UPS [Advice PRD650]), and connect the UPS directly to prevent or reduce the chances of fire?

@dor123: The surge protectors have to contain a fuse in series with each MOV to make sure the fire would not start in case the MOV fail.
The MOV tend to lower their voltage, when severely overheated and in that way they are supposed to blow their fuse.
The maximum fuse rating is given by the size of the MOV element, so above some size the 15A B breaker is supposed to work reliably as the MOV fuse, but these are really big and for sure they won't fit into any "extension cord" or "plug-in" protectors (they would require a box of at least PC PSU size). But even these have the required circuit breaker installed within the case, only it is in the line input, so it disconnect the load, rather than keeping it unprotected.
So all these plug-in or extension cord protectors have to have the fuses and the fuses have to be properly rated, with sufficient current breaking capability (so no glass 20mm jokes). The problem is, when the overvoltage happen, the fuse blow and keep the equipment unprotected. Therefore the MOV's have ~100kOhm resistor in parallel and parallel to the fuse is a neon indicator (include it's ballast resistor) ion order to provide a visual indication, than the protector is not protecting anymore.
So if the protector have all these things properly made, it won't start a fire. If it would protect anything, it is debatable, but it should be at least fire-safe.
Now I've seen many units sold, which do not have any such fuses, yet they were in very small boxes. These are the fire disaster really waiting to happen...

@Tree fire investigation:
But there is usually nothing left from the bulbs as well, the heat from the dry tree use to be so intense, they all burst on the thermal shock, so that evidence is destroyed too...

Have a look at "one of the most recommended by electricians" surge protectors sold here. MOV's are rated 275V AC. The specs claim "excessive oltage protection" at 275V. The relay card is for the low voltage - Yep they used the 4 comparator chip yet instead of implementing OVP and UVP on the chip they just left half of the chip unused. Many chaper protectors dont have the relay cardat all - only the one with the 3 MOVs

http://postimage.org/image/3w2cywtc5/

At first: Quite small MOV's and no fuses at all: I think I do not have to comment on that anymore...
At second: The relay is slow, so it can not be used for fast overvoltage response. Maybe the smaller, but steady overvoltage, dangerous for electrolytics and transformers, could be treated by the relay section well. But it does not replace the required fuse for the MOV's...

The undervoltage cut out is normally not as necessary with IT equipment, undervoltage should be handled well with the equipment itself.
Where it may become handy are the devices with an induction motor inside (like coolers, fridges,...), because if the motor loose it's torque, the slip in the rotor increase and may overheat it.

Open neutral with its 300-400V won't damage stuff "instantly" - not even IT stuff (main limit there is the electrolitics, the primary silicon is usually 600V+). Sufficient time to open a relay

That is the mild overvoltage, where the relay have the chance.
But it is true, than the open neutral could first demonstrate itself as an undervoltage, in such case the board have the chance to disconnect the relay before any overvoltage actually appear.
But then you loose the capability of the computer PSU's to cover for voltage dips (e.g. caused by the starting AC compressor).

Well, what I'm missing there at most are the fuses, as that is, what make this thing very dangerous. There should be two, one in the phase and one in the neutral...

That for one, but other thing i dont htink is right is why the MOVs are rated so low ? Put in 450V MOV's, thats just above the reach of open neutral (so it very reduces hte chance that the MOV will ever be subjected to continuous overvoltage), yet low enough to save the silicone as far as MOV's have a chance to do that at all

Their prime functionality is to protect the electronics from high voltage, high current, but short time spikes. The 275V (it mean the maximum rms AC voltage before it activate, so the current start to flow above 400V of the actual, instantenous voltage) MOV is already barely able to keep the peak voltage below 500..600V during the event, what is the limit, when many of the components could survive as a single shot event.
450V MOV's would overshoot to more than 1kV, what mean they won't protect anything.

@Christmas tree : "t would take too long time to trip the C16 breaker"
Well, for home wiring the correct characteristic is the "B", the "C" is too slow to protect against wires overheating. Don't forget, the wires have to always have enough temperature margin to safely handle the short circuit current before the breaker really open the circuit, even when they are preheated to any point just before the breaker open on the thermal trigger.

The "C" is intended to protect lighter electromagnetic components (about 1 second, so ballasts, transformers,...), so which have at least some thermal inertia to swallow overloads and which could cause short ovecurrent surge in few mains cycles on turn ON.
The "D" is intended for long inertie devices with quite long turn ON surge, like electric motors (many seconds) and so on.
These are then unable to protect the wiring, so the wiring should be made according to the upstream protection device.

Since I can't upload pictures, I will put the pictures of my Supco GPT SC9L surge protector here:

Is this surge protector a ticking time bomb that can explode at any time?

For sure these MOV's would not suffice with the upstream B16.
And I do not see there any fuses.
Maybe there is an attempt to create "fuses" using tracks on the PCB, but those would be more resistors and inductors, than reliable fuses...

So with what I know, I would count this as another "ticking bomb"...