rjbrown2

Are we in Handrail and Guardrail territory with this porch ? If I count correctly, we have six risers on the Stairs and the Elevation change of at least the Right side (as we view it) appears greater than 30 inches. <bb

I believe I live in the same GA county as Jim. This WH was installed in 2007 in one of the corners of my basement. Notice the TPV drain line eventually goes vertical and ultimately has 4 (maybe 5 if there is one on the outside wall), 90 degree bends (one at the top out of sight) <bb

Methane is not going to be the issue from an explosion in this set up. Methane (Natural Gas) is CH4 whose molecular weight is 16. Air has a molecular weight just over 28 (since it is mostly N2) The Methane is so much less dense than air it it will proceed straight out the vent. The culprit in any explosion in this rig would be Hydrogen Sulfide (H2S) whose molecular weight is 34. This gas is more dense than air and if it makes it up the vent to the fan 'junction' it could back spill into the bathroom. That being said, the explosion concentrations in air for H2S are from about 4.5 to 45%. This is so much higher than the allowable limits that if you started getting any serious H2S concentrations in the area, it would run you out from the irritation of your eyes, mucous membranes and lungs before there would be any explosion. Still wrong though. <bb

"As a rare householdeR WHO still has a landline...." There, I fixed it for you. <bb

Times change. A few decades ago we were having several near strikes per year taking out consumer electronics. Talked to the EMC (maybe there's the diff) and they installed a whole house surge suppressor for no extra charge or rent. Have no idea about the Joule rating though. GWTW I guess... <bb

"It is named after Tarhe (whose nickname was "The Crane"), an 18th-century chief of the Wyandot Indian tribe." from Wikipedia. And "vee-(slight space) HICKLE" is a common Southern pronunciation of 'vehicle.' Don't need no 'Lantic Trench...<bb

Thanks

Marc: I said it clumsy. Since the skin depth is almost total at 60 Hz (current flows across the whole cross section) that means that conductor resistance is dominant like you said. The resistance of the squashed area is proportionally higher than the wire gauge. Is there (a) NEC citation(s) that back up the need to do anything ? It looks like ©rap, but absent a 'violation' what ? How do we justify it ?

Actually when you cold work soft copper, you raise its tensile strength but lower its ductility. The problem it would face is vibration or frequent handling over some period could further work the interface between the soft and hardened sections leading to a brittle failure there. This seems low probability in a residential situation. An electrical question is that the skin depth of the current for 60Hz is significant. Reducing the cross section of the wire does what in near capacity conducting situations ? Seems like a hot spot is possible. Bare wire in an open area, OK ? Electrical experts please ?

The 'owner' of a name is the authority on its pronunciation. For instance here in GA we have a county, no doubt named after the Great Rev War guy, DeKalb. We pronounce it dee-CAB county. People from up North (Illinois and Indiana) correct us and say it is pronounced 'dee-CAWLB' county. When in Indiana etc.., but here etc. We also have another county "Taliaferro" You would never guess - TOLLiver (rhymes with DOLL-iver)

I haven't done this in a long time and I'm sure there are easier ways to crank it out on the internet, but I got out my Psychrometric Chart E-7 that came with my Thermal Environmental Engineering text by Threlkeld (1960s era) Assume upfront that 2 ounces of water (about 0.125 lb H2O ) remain available after the cooling cycle to go back into the air continuously passing over the coil. Assume at the end of the cooling cycle the air is sea level atmospheric pressure, 78F and an R.H. of 45%. I locate that point on the Chart and that the W (lbs water/lb dry air ) is about 0.0096. If we assume an 1800 sq ft home the the air volume is about 1800 x 8 ft = 14400 ft^3 with 8 ft ceilings and no furniture. So let's guess that we have about 10,000 ft^3. Using the specific volume on the chart at our point and inverting it, we get about 0.073 lbs air/ft^3. This results in about 730 lbs of air in our house. The increase in W is then about 0.125 lb/730 lb = 0.0002 lbs H2O/lb air. That bumps the number from 0.0096 to 0.0098. I have to estimate on the Chart, but it looks like about a 1% increase in the RH depending how long it takes to evaporate and assuming we don't start another cooling cycle before that is accomplished. The biggest error possibility I immediately see is the air volume estimate in the house. If I'm low the effect is significantly lower than 1% and if I'm high it could come closer to 2% I don't know how sensitive we are to 1 or 2% differences in R.H.

Marc I am familiar w/ Propane's refrigerant characteristics, but note its unlikely presence in consumer grade refrigeration equipment. I have experienced old SO2 refrigerators as I grew up in the 1950s with 'old' refrigerators

Marc: From DURACOOL's bolierplate: "In the United States it is illegal to use a hydrocarbon refrigerant as a substitute for a Class I or Class II ODS refrigerant for any end use other than industrial process refrigeration systems, or retail food refrigerators and freezers (stand-alone units only)." I think what you are referring to is Propane fueled absorption refrigeration systems that generally use ammonia as the refrigerant.

Could you make a life safety argument against an inward opening door ? A person who has become unconscious and is blocking the travel space for the hinged panels would make rescue difficult.

I understand bends like that can slow the current down from about 0.9 the speed of light to about 0.8.... The cyclic bending associated with manufacturing and installation is so mild that the EC copper would almost never be work hardened enough to fail on the rebend. But, I would leave it alone too...

And why does it appear to be plumbed for both H & C on an outside fixture ? Nice to have for some outside jobs.

The design principle that was beat into me about 50 years ago is that you locate assemblies and sub assemblies with details - not with fasteners. And fasteners should be loaded in their preferential mode - nails should be loaded in shear, bolt/nut combinations or machine screws primarily in tension etc.

I would infer that Mr./Ms Retail is regularly using some of the breakers in the panelboard as switches (and SWD marked breakers are rated for such use as I understand) The tape is there as a guide or reminder to 'Don't open these circuits' rather than some brute force method of keeping the circuits energized. I have worked in an operation like that years ago. Usually the circuits that are a 'natural' for that are lighting circuits.

Thanks Kurt - I see the left one disappearing into the dirt

My machine design 'perfesser' would not like that stress concentration point at the 90 degree bend. I would feel more comfortable with gusset plates welded on. That unit is going to be vibrating on the end of those cantilever beams for years and years. Oh, I'm sure they will be well tended, the rust wire brushed off, and painted regularly

Large parts of NE Georgia are served by the Jackson Electric Membership Corp that was formed in the late 1930s. Parts of Gwinnett, most all of Barrow, Jackson, and Madison counties are served by JEMC. It is one of the largest (by customers) electric co-ops in the US.

If I remember the rules for braces correctly (NG if less than 45 degrees) and following the basic trig here, the braces add nothing and may actually contribute to the load by their weight, No ?

Horse stuff was everywhere about 100 years ago when we just about all got our construction stuff together My Daddy was born in 1908. The first vehicles he remembered seeing were horse drawn wagons. Thus it had been for almost forever. Trucks were the first engine powered vehicles he remembered. They had obvious commercial value. Horse drawn vehicles were still around (for produce sales and junk collecting) into the early 1960s in my own experiences. We forget how central everything 'horse' once was to our society.

Jim: It looks like your cite clears it up for UF being Ok. Thanks The connections at the pump is not the condition I was concerned about. I was looking at the possible degradation of the dielectric strength of the insulation (both directly on the wires and any sheathing material) between two (or more) closely spaced conductors at different potentials. That possible degradation being a result of the 100x pressure driving water molecules into the polymer structures of cable not specifically designed for the application. We had to fight that battle decades ago in the communications cable field.

I don't know how much the physics gets into this but you can see that normally UF is going to be buried a few feet underground and if said ground is water saturated the max static head you would expect is a few feet. A well, on the other hand, could subject the UF up to two orders of magnitude (100x) the static head on the UF. Ever how much pressure is a factor in driving the water molecules into/through the polymer structure of the UF as opposed to the purpose designed submersible cable is the question that seems relevant to me.