You are thinking of the ones that are still standing. Not the ones that fell down long ago.
Omission of overload protection for resistive heating elements.
- Thread starter EFLImpudence
- Start date
You are thinking of the ones that are still standing. Not the ones that fell down long ago.
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You are thinking of the ones that are still standing. Not the ones that fell down long ago.
... but, as I said, also "Yes, it increases fault currents, which may damage things other than the cable".
I don't really think that is often going to be an issue but, as I hope you understand, was merely wanting to indicate that there are often "other sides to the argument" which may need to be considered.
Kind Regards, John
If you have say 12 conductors in a trunking and the system will only ever have current flowing in any 6 of those 12 ( for example 6 pairs of strappers for 6 two way lighting circuits ) then could the derating be for 6 conductors instead of 12.
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It's a razor sharp line between correctly, over and under engineered.
Let's be honest an 8x2 joist is perfectly acceptable in most domestic houses, in many situations a 6x2 or even a 4x2 may be adequate and a 12x4 is plain simply way over the top. So if a 4x2 is adequate where is the cut-off between adequate and over engineered? there again where is the cut-off between adequate and under engineered? Is it when the floor feels springy or when it collapses? If it's when the floor feels springy is a sprung dance floor under engineered?
The fact an engine is still working 100 years beyond it's useful function possibly means it's over engineered, certainly it could possibly have been produced more economically.
But then we have to look at the victoorian properties/engineering which has failed so miserably, my first house (According to solicitor built 1891 but vendor claims it was built by his father in law as a wedding present in 1926) had only bricks laid on their side for foundations and one side wall was obviously lower than the other and it still had regular movement until I moved on in 1992. the adjacent road had a terrace of >50 houses built between 1888 and 1923 according to the plagues, the window and roof lines look quite bad with the subsidance.
Let's be honest an 8x2 joist is perfectly acceptable in most domestic houses, in many situations a 6x2 or even a 4x2 may be adequate and a 12x4 is plain simply way over the top. So if a 4x2 is adequate where is the cut-off between adequate and over engineered? there again where is the cut-off between adequate and under engineered? Is it when the floor feels springy or when it collapses? If it's when the floor feels springy is a sprung dance floor under engineered?
The fact an engine is still working 100 years beyond it's useful function possibly means it's over engineered, certainly it could possibly have been produced more economically.
But then we have to look at the victoorian properties/engineering which has failed so miserably, my first house (According to solicitor built 1891 but vendor claims it was built by his father in law as a wedding present in 1926) had only bricks laid on their side for foundations and one side wall was obviously lower than the other and it still had regular movement until I moved on in 1992. the adjacent road had a terrace of >50 houses built between 1888 and 1923 according to the plagues, the window and roof lines look quite bad with the subsidance.
You're probably not disagreeing as much as you think. You're really just saying that if one over-engineers things, they are likely to last longer - which is almost a statement of the (usually) obvious. The question relates to how sensible it is expend a lot more time/effort/cost, and use much more resources (trees, clay, steel etc.) in order to achieve a product which may last longer than an alternative which would probably last at least 50-100 years.
The "least material and labour costs" which constitute a reasonable compromise between cost and the other relevant considerations.
Of course, that's why the totality of my sentence indicated that I was talking about those who were "...knowledgeable, skilled or experienced enough to understand (or be able to determine) what is a reasonably 'adequate' compromise". If they were not knowledgeable/ skilled/ experienced enough to understand that then, yes, they could easily "come a cropper".
Kind Regards, John
Yes and I have no reason to disagree with you.
Exactly my point - and as would be confirmed by engineering calculations. The only sense in which 12" x 4" ones would lead to greater longevity of the building is if they suffered from very severe deterioration (rot, insect attack etc.), but I'm not sure that it's sensible to design on that basis. ... and similarly with the 2½" and 3" water pipes they installed in my ('domestic') house!
That's essentially the same as I just wrote to bernard. Marked over-engineering will very commonly result in increased longevity but, with some exceptions (like major civil engineering works), the question is whether the 'cost' (in the widest sense) of doing this is 'sensible'. Over-engineered Victorian machines might well still be working today, because they are over-engineered, but they very probably will be very 'technologically obsolete' by now. An extremely over-engineered (and very expensive) computer built in the 1980s might still be 'working' today, but what use would it be to anyone?
Kind Regards, John
No really, it's not only the current running in some of the conductors, it's also the lack of ventilation. Hence the difference between surface mounted and buried.
One has to remember bigger pipes are required for lower water pressure and that was an issue in yesteryear and from your descriptions you have a big house, potentially several floors and extra taps.
Good try, but I don't think you are getting them off the ('over-engineering') hook all that convincingly
The main supply pipe, to water tank which was on the second floor, was pretty modest (probably 1"). The 2½" and 3" pipes were, it seems, mainly those from that tank (and from the DHW cylinder, on 1st floor, apparently originally heated by an {Aga-branded} coal-fired boiler in the cellar) to taps on ground and 1st floors. ... and the pressure created by a 1-2 storey head of water was obviously no different in yesteryear than it is today!
This was obviously nearly all out-of-service (although a few of the large pipes were still in use) by the time I moved in (about 35 years ago) but many of the remnants (including the Aga boiler and a massive out-of-service water tank) still remained as 'reminders'!
Kind Regards, John
Are they definitely water feed and not heating pipes?Good try, but I don't think you are getting them off the ('over-engineering') hook all that convincingly
The main supply pipe, to water tank which was on the second floor, was pretty modest (probably 1"). The 2½" and 3" pipes were, it seems, mainly those from that tank (and from the DHW cylinder, on 1st floor, apparently originally heated by an {Aga-branded} coal-fired boiler in the cellar) to taps on ground and 1st floors. ... and the pressure created by a 1-2 storey head of water was obviously no different in yesteryear than it is today!
This was obviously nearly all out-of-service (although a few of the large pipes were still in use) by the time I moved in (about 35 years ago) but many of the remnants (including the Aga boiler and a massive out-of-service water tank) still remained as 'reminders'!
Kind Regards, John
I'd whip them out a sell the lead.
Yes, definitely. there was almost no wet heating - just a couple of small 'gravity fed' radiators on the ground floor. By the time I got here, there were electric storage heaters all over the place (which I immediately removed), but the traditional heating had clearly all been by open coal fires, with at least one fireplace in every room (and more than one in some), most of which still exist.
Nearly all iron/steel, not lead. Almost all of it (and the fairly small amount of {small} lead pipes) was sold (for a pittance) many years ago! The only bits left are those which would be a PITA to get out.
Kind Regards, John
in '86 I was loaned to London BT and elected to stay with a friend during the week to avoid the cattle run. it was also financially worth it. During the time with her she moved house and I stripped all the old gas and water pipes out and replaced with copper while installing a combi boiler and CH and a total rewire.
There was also some rotten ground floor joists and floorboards and little sand, cement, plaster etc. to brick up a couple of fireplaces.
I can't remember the figures but the scrap lead pipe more than covered the cost of all of the new pipe, fittings, rads and rewire. The final cost of all that was less than the VAT free price of the boiler.
Indeed. Lead pipe (or lead anything else) is certainly worth selling, but when it comes to iron/steel (which is mainly what I had) one almost has to pay people to 'take it off one's hands'!
Kind Regards, John
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