Why no AFCI for 230V? - Page 1
Forum section: electronics / general

author: Connoiseur
author_rank: Regular Contributor
timestamp: February 11, 2016, 09:09:30 am
content: I looked around the web but couldn't find any satisfying answer.I guess they are mandatory in the US for all households.Does Britain and other nations that use 230V mains don't care about arc faults or the wiring code somehow ensures that every joint is tight like a weld? OR, lower current per VA reduces the chance of getting an arc fault?

author: coppice
author_rank: Super Contributor
timestamp: February 11, 2016, 09:32:49 am
content: Quote from: Connoiseur on February 11, 2016, 09:09:30 amMy experience of faults in UK wiring which resulted in overheating is they don't usually involve arcs. Dirty contacts, or contacts with inadequate pressure usually result in excessive resistance, heat buildup and the melting of plastic fittings. Something usually gives before these problems result in a fire.I wonder how the rates of electrical fires compare between the US and Europe, how many US electrical fires can be traced back to an arcing connexion, and how much the difference in building materials might affect things?AFCIs aren't a panacea, as they can be troublesome, tripping on false alarms.

author: rob77
author_rank: Super Contributor
timestamp: February 11, 2016, 09:40:56 am
content: i think the major reason is the fact that 99% of buildings and houses in Europe are concrete or brick+mortar, no wooden houses over here. (except cabins ...etc... and some rare exceptions ).the risk of catching fire is almost non-existent if the wires are buried in the non-flammable concrete/brick walls.

author: coppice
author_rank: Super Contributor
timestamp: February 11, 2016, 09:49:46 am
content: Quote from: rob77 on February 11, 2016, 09:40:56 amHave you never watched the Towering Inferno?The plastic insulation, conduits and fittings for electrical installations are supposed to be flame retardant. However, there are:plenty of decorative materials in most houses to get a fire goingwooden upper floors and roof frameworks in most brick houses

author: rob77
author_rank: Super Contributor
timestamp: February 11, 2016, 09:58:08 am
content: Quote from: coppice on February 11, 2016, 09:49:46 ammy point was that if a broken wire arcs inside a concrete wall - there is nothing to catch fire... it will arc/burn itself to open circuit and then it's over. (e.g. wire broken due to thermal expansiion and contraction)

author: Cubdriver
author_rank: Unknown
timestamp: February 11, 2016, 11:53:19 pm
content: Their purpose is to protect against arcs that occur in devices that are plugged in, not to protect the wiring itself. Think for instance of an extension cord that becomes worn and develops an intermittent connection due to broken wire inside. It could begin arcing at the point of the break. The arc wouldn't trip a breaker (it's not drawing excessive current), but, being an electric arc, is very hot and could ignite the wire insulation. Another example would be an electric blanket - fine heating element wire in something that's folded and flexed a lot. If a wire breaks, you could have a nice hot arc that's literally buried in fabric. Poof, fire. Yes, I know, reasonably conscious people would figure out that the cord or blanket was bad and simply replace it, but unfortunately there are a lot who would ignore it or be too oblivious to notice UNTIL the house burned down, and we need to protect those people from Darwin's wrath.The earliest code in the US mandating them called for them to be used in circuits feeding bedrooms; that's the one I had to follow in my home rewire. The newer iterations may be more stringent and require them in more areas; I don't know as it's not something I currently need to worry about.That being said, they're a royal PITA when you're working - I need to plug my miter saw into another receptacle downstairs to use it (cutting trim and flooring for instance) unless I want to get a LOT of exercise running back and forth from the third level to the basement to keep resetting the damned thing, as it seems to trip off on every second or third start of the saw. My now ex found it hysterically funny to see me storming up and down the stairs swearing like a sailor and getting progressively more pissed with each subsequent trip until I finally got smart and plugged it into the bathroom receptacle (GFCI rather than AFCI protected).I suppose in the grand scheme of things they're beneficial, though at the same time it's annoying to be forced to install expensive devices that really are only rarely if ever going to save the day, but in the meantime can be an ongoing annoyance when trying to use power tools plugged into the receptacles that they feed.-Pat

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 12, 2016, 12:02:31 am
content: I wonder what the ratio of electric fires between Europe and America is.My fleeting suspicion is that Europe has much fewer accidents per capita and per kilowatt.

author: station240
author_rank: Unknown
timestamp: February 12, 2016, 12:24:50 am
content: It could be argued the US ~120V circuits have twice the current for a given power output. Hence arc faults have twice the fault current and more likely to start fires.The current if what does most of the physical damage to conductors in arcing.

author: Someone
author_rank: Super Contributor
timestamp: February 12, 2016, 02:36:04 am
content: I haven't pulled up numbers for Europe but there are good number for Australia to hand. From the wikipedia AFCI page it is claimed there were 40,000 house fires attributed to electrical faults in 1996, when the population was 270,000,000 and there was approximately 12EJ of production. For New South Wales (a large state of Australia) in 1998 the fire service had 540 house fires attributed to electrical faults, when the population was 6,300,000 and there was approximately 2EJ of production Australia wide (18,700,000 population).So we have a rate of electrical house fires as:US: 150/million population, 3300/TJAustralia: 85/million population, 800/TJ

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 12, 2016, 02:57:51 pm
content: I'm looking at European statistics but none so far seem usable.One gives the results in percentage, one does not distinguish electrical from others, one only lists accidents resulting in death. Completely useless so far.

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2016, 09:48:04 pm
content: Quote from: rob77 on February 11, 2016, 09:40:56 amUmmm… that may be true for most modern construction in continental Europe (for sure it is here in Switzerland), but there's plenty of old wood construction (for example, brick and mortar exterior walls, but all wood for the floors and interior walls), farmhouses, etc. And in some places (like the UK and northern Germany) you see plenty of wood frame construction. (In fact, it's making a comeback here, as a supposedly ecological/sustainable construction option.)The wood frame construction style commonly used in USA is derived closely from English construction, primarily.

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2016, 09:49:23 pm
content: It would also be really interesting to see what Japan's electrical code requires, since they build their houses literally out of wood and paper (with design lifetimes of <30 years), and use 100V power, so potentially even higher currents than American 120V.

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2016, 09:53:42 pm
content: Quote from: Connoiseur on February 11, 2016, 09:09:30 amDifferent countries adopt guidelines at different rates, it's not necessarily indicative of relative hazard.In any event, they do exist. I found them at the local electronics distributor without much fuss. Here's one:http://www.distrelec.ch/en/arc-fault-detection-element-1mw-16-230-vac-siemens-5sm6011/p/11030400

author: XOIIO
author_rank: Super Contributor
timestamp: February 13, 2016, 03:00:55 am
content: Quote from: tooki on February 12, 2016, 09:49:23 pmI'm not sure if it was just because they were far away but even in the smaller towns/communities that farmed rice or other things the houses seemed somewhat modern, and what was really cool is that there was loads of solar power, sometimes just the water heaters on the roof, but also a lot of proper solar panels, and man it would be the perfect climate to do that in, I bet that you could go entirely off-grid quite easily.edit: Vietnam would be one to check up on, the wiring there is just... well it's something else, it's probably all been added in later on, let me see if I can find a picture of the "outlet" that was in one place I stayed, it's amazing. Basically like a big breadboard. And this is 220v too.

author: IanB
author_rank: Super Contributor
timestamp: February 13, 2016, 03:07:32 am
content: Quote from: Connoiseur on February 11, 2016, 09:09:30 amI think AFCI's are an unnecessary waste of time and money. I can only think they are mandated because someone, somewhere, is getting rich on the deal.

author: XOIIO
author_rank: Super Contributor
timestamp: February 13, 2016, 03:15:19 am
content: Here it is, I was going to post a whole thread about it but totally forgot when I came back lol. The wires behind the back section were a complete mess from what I could tell, but the burn marks really did it lol. Had to use tape to try and get the fan to stay plugged in properly.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: February 13, 2016, 03:09:26 pm
content: Quote from: tooki on February 12, 2016, 09:48:04 pmI'm actually more surprised by that than I should be, but that's probably because my particular corner of the UK has traditionally used stone brick construction due to easy access toa relatively decent but easy to work building material.Given its price premium though red brick is pretty much the standard for all but the highest end new builds now though. For some reason timber frames haven't caught on around here for the most part and if the walls aren't load barring (only common in newer* homes) we use steelBut if I look at older houses from other parts of the country and compare that to the common representation of a traditional American house the similarity is much more apparent.*Though newer around here is probably old by a lot of places standards, but that seems to be true for a lot of Europe.

author: langwadt
author_rank: Super Contributor
timestamp: February 13, 2016, 04:26:25 pm
content: Quote from: Mechanical Menace on February 13, 2016, 03:09:26 pmafaiu much of the reason why places like London is mostly brick is because after the great fire houses had to be made from fireproof materials

author: IanB
author_rank: Super Contributor
timestamp: February 13, 2016, 05:00:22 pm
content: Quote from: langwadt on February 13, 2016, 04:26:25 pmThat was 350 years ago. I don't think it is quite relevant to how modern houses are constructed.The truth is that timber framed homes are generally erected by the large companies like Barratt who want to put them up quickly and move on. Homes with all brick construction need more skilled labour and take longer to build and are generally put up by smaller builders.There's nothing actually fireproof about brick buildings since the furnishings, floors and roof joists are all made of wood.

author: Ian.M
author_rank: Super Contributor
timestamp: February 13, 2016, 05:41:45 pm
content: That's why building codes require firewalls between terraced or semi-detached dwellings. Older dwellings have the actual firewall protruding from the roof between it and the adjoining property.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: February 13, 2016, 06:15:53 pm
content: once the room contents are fully engulfed then no material will stand up to it.think about the energy content of something like wood or a couch.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2016, 11:19:27 am
content: No materials? Firewalls can send do protect adjacent buildings. A couch doesn't have enough energy to melt bricks.