Neighbors house blows up
- Thread starter n8huntsman
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CCTVCam
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- Sep 25, 2017
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Can't really see an issue. I guess cables are probably routed through holes in the metal struts lined with grommets, and the metal frame is probably earthed as a precaution. Don't know what electrical safety standards you have in the US, but in the UK, all newer installations and rewires are on safety breakers,so sensitive they trip at milliamps and so fast, you can't get electrocuted. In fact they're so sensitive there have to be 2 standards as lights would trip out mains breakers when switching on.
tangent
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- May 12, 2016
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In the US most things are on AFCIs now which help prevent fires and in some cases might prevent a shock. Generally though GFCIs are what's needed for shock safety and we don't require those on most things except outside, kitchen, garage, and bath.
The split/dual rail distribution board (consumer unit) is set up to have RCD only covering the mains power outlets and so trip quickly in the event of a leak to earth etc. The lighting isn't RCD protected but covered by the master breaker only, so that you don't get left in darkness when a fault happens that trips the RCD on the power side. It's not the turn-on surge on the lighting that trips the breaker anyways but more when an incandescent element fails, causing a big surge current draw.
Never had that happen, when you walk into a room, turn on the light and get a brief flash of light accompanied by a plink sound and then all the lights go out?
Incandescent bulbs (tungsten filament type) are in effect a resistance wire, heat and thereby light is the by-product of the current passing along the wire. When they fail, depending on the failure mode, they sometimes will draw a larger than usual current at the moment the element burns out and breaks, as its resistance drops lower than at manufacture time. That momentary current surge is what blows the fuse/trips the breaker on the circuit.
It's nothing to do with RCD protection, I've had places pre the dual rail distribution boards where the whole house was covered by RCD including lighting, as well as dual rail. Same results, only time you get a RCD trip is on a short/earth issue as you'd expect, or a bulb blowing which usually only takes down the local circuit breaker and not the main RCD. Probably become less of an issue in current days tho as most of us have moved to LED or other low energy solutions, never had a circuit trip since doing that, yet...
CCTVCam
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Not the way mine was done, which was done to code (at the time). I have a split distribution consumer board - 1/2 half has breakers for mains, the other 1/2 breakers for lighting.
They really are fast though. I made a mistake a while ago by not disconnecting live and neutral whilst repairing something and the breaker kept tripping. Never felt a thing. It was only when I worked out why - ac - travels both ways, I realised my dumb mistake, but the breaker saved any shock.
BTW tungsten bulbs can trip certain MCB's even if not faulty. I believe it's something to do with the way they switch on and certain types of breakers sensitvity.
As for LED lighting, my whole house is on LED. Far superior to tungsten and the savings are huge. An 8W LED bulb has an output exceeding a 60W tungsten and you can get them in any colour from ice white to traditional tungsten yellow.
I wouldn't recommend anything other than LED and they're ideal for CCTV as you can get daylight matching bulbs with a high CRI.
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that sure doesn't look like a dual rail setup but a single with the RCD protecting the entire single rail. Dual rail units tend to have a separation between the 2 rails. As for breakers yes there are some more sensitive fast-trip types just as there are slow and fast blow fuses. For homes you'd not normally fit fast trip ones (other than the RCD itself that is) to avoid false trips, all classic incandescent bulbs are fairly low resistance when cold with resistance increasing as they heat up, much the same as switch-mode PSU's are, so high wattage and some bulb types may well pull more current at power on.
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On a dual rail board you'd normally have the main switch and a group of lighting breakers, then a small gap before the RCD followed by the main power rings, kitchen and shower that it protects.
adding:
On a dual rail board you'd normally have the main switch and a group of lighting breakers, then a small gap before the RCD followed by the main power rings, kitchen and shower that it protects.
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Yes, I've seen this with high-wattage stage/theatrical lighting. 575W and 750W halogen bulbs will sometimes go bright blue or red for a few seconds before popping (which can sometimes sound like a gunshot).
Bradmph
Pulling my weight
tangent
IPCT Contributor
- May 12, 2016
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It's actually worse today than it used to be. Open floor plans, more particle board and chip board in the build and furnishings, thinner flimsier doors = houses engulfed in flames much faster
After watching a number of house fires on YT (my 5yo is into that right now), it always strikes me how people react while the fire is still small - and appears manageable. I know with popping ammo and fuel-supplied fires, it's hard to make a dent from a distance, but still... When the door first blew out, if the girl that ran up and started dancing had simply grabbed a garden hose - well before the black smoke and massive fire - would that not have provided some relief? At a minimum, it may have delayed the spread and bought more time for fire rescue to get there.
MMQBing is easy, I know. But I can't help but think if that was to happen to me, and I was a witness from early on, I would try to actively suppress the fire.
MMQBing is easy, I know. But I can't help but think if that was to happen to me, and I was a witness from early on, I would try to actively suppress the fire.