I was called to work on some sewage pumps; the plumber told me that the customer was insisting on "an electrician who was familiar with and an expert on such systems" Ohhh Kayyy....
Being Nevada, this entailed a trip halfway across the state, into what we call the 'cattle counties.' Well, it was a perfect day for a drive in the countryside. The directions were simple: keep going untill you gas gauge drops below view, then turn left
I arrive, and within seconds I am able to identify (from the panel) one bad float and a bad pump. Replacements were procured, and the installation repaired.
Only then did I learn that the 'customer' in this case had an engineer for a husband, some technical training herself, and that both their fathers were on site. One had retired from NASA as a pump and control engineer.
The extreme rust on the old piping was a shock to the engineers; they had never realised sewage was so nasty. Expressing surprise that the Myers pumps did NOT have a fifteen year warranty - I'm not aware of any sewage pumps with more than a three year warranty - they paid for new pumps.
I went on to explain how the floats operated the pumps; this was a mystery to them. the wiring diagram - conveniently intact in the panel after 15 years - made as much sense to our engineers as a Chinese phone book, so I explained the symbols to them.
It seems that they had all tried to 'figure out' what the problem was, and had been baffled. The visible sparks within the 'ice cube' relays as they operated worried the customer. They were worried that they might need to replace a $1000 panel (they didn't).
Well, it's nice to be appreciated. I was also amused when the NASA guy explained to his daughter that I was not 'hindered by an engineering education."
BTW: I'd be very disappointed in any journeyman who would not have been able to identify the problems.
To the casual observer in a typical French bar, eavesdropping on the conversations of the ubiquitous British Expats propping up the latter, it would seem that there are only 3 subjects of conversation. The exchange-rate pound to euro, the extortionate price of ferry tickets to Blighty for the essential supplies of Hienz baked beans and back rashers, and the French Sewage System: Lack Of. One would have to live in a pretty remote and ramshackle hovel in England which did not enjoy the benefits of a mains sewage works and sewers, loving laid at 1 to 100 falls, for the Victorians just loved digging gurt big 'oles and laying bricks and pipes.
To comply with new environmental laws, [ essentially the crazy idea is that the French have to make a passing stab at treating sewage and not pour it into the nearest ditch- at least that was an improvement on chucking out of the window! ], we had a new system put in in 2005, which cost me half the price of a new car. It has two pumps, one on the exit from the 4000 litre septic settlement tank, to pump settled water to the sealed vertical filter bed [35 cubic metres of sand], and one to lift the filtered water from the filter base and.....er.....pump it into the nearest ditch!
All approved by the highly compensated Engineer lady from the Prefecture, of course, who stomped round inspecting stuff and pontificating over her drawings, while our installer muttered vieled oaths under his breath in patois.
In 3 years, the sewage had eaten right through the support chains on both the expensive immersed pumps, 1/4" thick hot-dipped galvanised steel. The septic tank pump failed at the same time, the raw sewage had got past the seals into the armature and eaten it too. I baulked at the price of a new pump, and got an all plastic pump, capable of handling solids, in the UK for a fifth of the price. System over engineered, you see, by folks with lots of brains but little practical know-how. There was no need for giant pumps capable of hurling the entire contents into the filter in minutes. We only use 150 litres of water per day, so a 500W pump will eat the job. Yes it takes half an hour and not 5 minutes but so what?
We got two neat little battery powered gizmos that whistle if the pumps fail, BTW.
Every time I get together with some of my old college friends who went on to become engineers it takes me 2 or 3 hours of speaking intelligently to remind them I'm not a knuckle dragging moron just because I didn't go into engineering.
The looks on their faces when they realize I can comprehend what they are talking about is hilarious. You should have seen the reaction when they found out I knew what a Class 1 Div 1 zone was. And even funnier is that THEY didn't know what publication called out the classes! I have no idea where they found out what it was, it was something they needed to know to design certain sensors they were building. And I have to go through the same routine every year or so!
I'm sorry I was thinking about the other topic sorry.
I suppose they say 20% is OK because that is the tolerance of a cheap resistor. I knew guys who put pots in the circuit, adjusted them until things worked then took them out, measured them and replaced them with a fixed resistor. Anything not to do a little math I guess. That was before the calculator tho.
In Austria everything flows into a big tank which is pumped regularly by some nice guys in a big truck, the contents are taken to the nearest sewage treatment plant. Beware if the cesspool overflows... i know a house where the basement was closed off for months after that happened, don't know how they cleaned it in the end.
Cost estimating: Sum up everything you might need in a project, add 20% safety, double that figure and add another 50% secret factor. The end result is likely going to be close enough. That's how they did it where I used to work. The HVAC planning guys 2 floors above didn't even bother to sum up everything they considered reasonable, instead they made something up that sounded good for the customer but in fact had no idea what they were doing until final planning stages when they did all the calculations.