When this place was rewired (about 23 years ago) the RCD was tested. It went at 30mA so I asked for 25mA and it tripped. It didn't go at 20mA, which was a relief. Never had a false trip on it in all that time but it's still OK.
are potatoes fruit?
It was also a gross simplification because the original plans were to specify in more detail what the 5 must be - i.e. less than half to be fruit, and potatos don't count at all, but that got dropped for being too complicated.
At the time, there was the strong belief that eating lots of anti- oxidants would mop up the free radicals which cause damage to cells and DNA in particular. However, although a reasonable hypothesis, no one has ever managed to show any such effect operates at all, in spite of many attempts to do so. So the next hypothesis was that the health benefits come from the nutrients in the fruit and veg. That too is proving elusive, at least at the levels of consumption recommended. A study in New York showed that nutrient deficiency doesn't start kicking in until you get down to the level of around
3 portions of veg per week. There is no question that a higher fruit and veg diet is beneficial, and it's now looking like the benefits appear to be caused by eating more fibre and less meat, for which real evidence does exist.
That would be difficult to replicate in Glasgow. It would be hard to find a control group eating more than 3 portions of veg a week.
Owain
I don't drink potato-derived alcohols.
Vanilla is definately a fruit, and I had two portions of vanilla cheesecake last night.
Owain
Stem tubers.
Again not a certainty. If you apply 50mA of leakage to both devices, they will in practice trip in the same time. (this is the reason you need a time delay in the upstream device when you need cascaded RCDs).
The only situation that the 10mA device will trip sooner on is on a slowly increasing leakage current, or a step change to a leakage current above its threshold, but below that of the 30mA device.
That is within normal spec for a 30mA RCD. The normal test procedure for a RCD is:
Check no trip at 50% of operating current.
Check trip at 100% within 200ms
(or for devices with a time delay (type S models) then 200ms + the time delay).
Check trip at 5 x trip current happens in 40ms or less
Note also the specs often allow for the device to trip from anything about 66% of the stated trip current. So a 30mA device tripping at just over 20mA is "ok"
In reality they are usually better than the spec suggests - you will normally get a trip under 40mS for any tripping test current, and frequently under 20mS
In the context of electrocution, almost certainly true (excluding lightning strikes). However, I'm pretty sure the older bakelite phones have been used as a very effective club as well as employed to garrote an assailant or victim.
75 volts rms, afaicr.Your'e thinking of the -52v dc line voltage wrt earth.
These days, you'd use a DECT handset in preference to a wired in telephone instrument. No electric shock hazard whatsoever (typically
2.4v NiMH battery pack). A DECT phone is a safer option when using the phone line during a local thunderstorm, particularly when the line is an overhead dropwire from a street pole and especially so when you're on the end of a long rural run of overhead cable!
The British & American military did experiments on their own soldiers too. Somebody (military? I can't recall) did a bunch of nasty experiments specifically on black men in the USA too.
Therefore electricity is safer if you're not clean.
A 30mA RCD is allowed to take up to 200ms to trip with a 30mA imbalance. The
40ms time limit applies at 5 x 30mA.
I think there was good evidence in the 1970s in the USA that there would be big benefits to public health from getting people to eat less meat & dairy, but promoting that idea was politically unacceptable so it got turned into "eat more fruit & veg", which effectively meant "eat more".
Most people would retch if given a bowl of double cream to eat and then a bowl of sugar to eat. However, mix them together ( = cheesecake), and very few people have a problem eating that! Cheesecake is a strange effect...
No, it's the "perfect mix" of fat and sugar in the confection. The processed food industry have known and used this basic knowledge for nigh on a century to pander to our tastes and turn us all into food junkies.
This perfect mix of sugar and fat never existed in nature until cooks and chefs invented new recipes using raw cane sugar that was being imported in meaningful quantities sufficient to interest the fledgling "Food Industry" during the late 19th century (circa 1880).
I could say more (indeed, I've just snipped 3 or 4 paragraphs), but I'll save you the bother of reading any more 'tripe' regarding the food industry and the nation's obesity / diabetes epidemic and the 'blame-game' between consumers and the food industry over the profligate use of sugar in recipes not normally associated with 'sweetness' as a flavouring concept (not forgetting to blame HMG for a complete absence of moderating regulation which could so easily have mitigated the consequences we see today).
That's not been my experience. The general problem in the US is loose wirenuts. US wall boxes are not that easy to wire IME, the space tends to be a narrow rectangular slot and a lot of wire finger pushing is necessary in order to get the sockets positioned relative to the front cover plate so that the job looks clean. Add in that often the wiring is in "flexible" steel conduit and has box connector pieces which take up space. Ceiling junction boxes are very shallow and not all lighting circuits are wired as radials, even if the spec requires it!
The arc fault detectors fitted in some circuit locations can be a real problem with false triggering due to lightning or switching spikes. I dislike US plugs and sockets from a wire connection viewpoint, but quite a few UK wiring products are equally bad.
That might be "cheesecake" but it's not cheesecake. There's no cheese in it.
That's freedom for you. Or is it profit. Banning some foods wouldn't work anyway.
NT
If I had to make a guess, I would say an average of approaching zero per year.
The RCD I tested today whilst doing an EICR did not work.
The test button on the RCD failled to trip the RCD and nor would the 300mA I eventually tried on the 30mA RCD make it trip. Installed in January 2008 and this was a reasonably good installation (I found a few snags).
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