on willas comment about the breaker box. the reason a fuse is safer than a circuit breaker is because it relies on a fuse element that the power has to pass through. If too much energy is put through, such as a short or by overloading the wire reaches its maximum and burns out.
a circuit breaker is a mechanism that senses the current draw and if excess current is detected it is designed to open the circuit. They can stick. If you have a short and the breaker sticks the wires leading to the breaker can get red hot before the wire burns and acts as a fuse but that might accompany a fire in the wall.
for this reason I would replace vintage breakers. they dont often stick but relying on really old parts could cause a failure. it is possible.
fuses are so simple they really can't fail , they cannot stick, they have no moving parts. just dont put pennies behind the fuses, that will basically eliminate them and its a stupid old trick that is dangerous. its worth checking to be sure others have not resorted to that. just unscrew and look. no penny - good ( if you don't look you can't see the penny)
and yes someone could try to reset a breaker or replace a fuse while you are in some other room not communicating so if there are others at least use a sign. locking the breaker is prefered and often the only legal way. If I work on machienry I must lock it out not just turn it off, that's the law.
the 1/2" designation comes from 1/2" pipe. it refers to the inner diameter of the pipe not the physical size of the fitting so it will look larger than a 1/2" bolt. more like 3/4...
the threads on pipe fittings are tapered so that they tighten up as they are tightened to prevent leaks. you can wrap the threads in teflon tape but if they are brass it may not really be necessary. the teflon lubricates the treads and helps it seal but the pipe thread fittings should seal without it. it can help prevent rusting together somewhat.
NPT is common. unlike regular nits and bolts you dont have "metric NPT and standard NPT" just NPT ( national pipe thread) other fittings can have all sorts of threads but this is about the pipe connections. usually plumbers use the white tape gas fitters use a thicker yelow tape and you can also get stuff in a liquid or gell form.
backflow preventers are designed to shut if they see an improper pressure differential. I know a bit about them as I am being trained to repair them by a team of plumbers but it really isn't my job. they protect the city water from becoming contaminated by a user feeding water into the system. you have to be trained to service them here in Canada there is a ticket for that in addition to a plumbers ticket. I'm not sure if they are used in new houses or just commercially but they are required in certain circumstances and you can check the law rather than me being off track with the laws. these backflow preventers are quite expensive.
the hose bib outside will crack when it freezes unless you have a second tap inside. If you ave that second tap you can open the tap outside then close the one inside so that the outside tap doesn't have water in it otherwise it can freeze and break from the water expansion. 3/4 is a big one you can probably use 1/2 unless you need a big sized garden hose. I put a big one in case I clean gutters and such and I run it at full street pressure so it is before my regulator. I figure it is also good fire safety to have a big hose at street pressure. mine relly blasts the water my city might vary but its normally a lot higher than my house pressure.
check if you even have a pressure regulator in your house. it will limit the pressure in the house to about 25 lbs or where it is adjusted to. mine did not have one so my old plumbing was seeing high pressures and that could cause a failure in old piping. how that surfaced for me was when the water tank started blowing its pressure relief valve and spilling water. old houses might not have ever had one, mine did not so I put one in.
if you want to check your house pressure you might have a fitting that looks like an air valve on a tire , a schrader valve. a water pressure gauge or a tire gauge will work. you can also thread a fitting onto any tap to check it. if you do have a pressure regulator this valve connection may be part of it so look there first.
if you like you can install a hose bib that has the shutoff inside the house where it is warm. this will prevent you from forgetting to open the outside tap and close the inside one. if you forget the outside tap will freeze and break. this will prevent that scenario. here is an example of that. its long and the tap opens and closes the valve which is inside the house where it is warm.
https://www.homedepot.ca/product/aqua-d ... 1000117469perhaps what your plumber was referring to is something like this
https://www.familyhandyman.com/plumbing ... or-faucet/note the following:
"Second, an anti-siphon device (vacuum breaker in a water spigot), now required by all building codes, is built into some new sill cocks (or can be added on to existing ones; step 11). It prevents unsanitary water from being pulled back through a garden hose and contaminating your water system."
I think its unlikely you will ever backfeed the water system with your garden hose. maybe if you hooked it to a pump backwards or ran a really long hose up a very steep hill you could put pressure on the system but it seems very unlikely... evidently this must be a possibility so the city wants assurance against people contaminating the public potable water system so laws like this are perhaps getting more strict. you'd have to do something strange for that to happen but It is possible to contaminate the system and that's something they are trying to safeguard against. it could make a lot of people sick if one person did some really dumb thing like pumping dirty water from a hot tub into the city water system. this doesn't look so serious as the backflow presenters I am being trained to repair. I didn't get time to do the official course, I was just herded into a situation and I will help the ticketed plumbers and they are helping me understand how to troubleshoot them they connect some fancy gauges to measure different pressure differentials . I am not a plumber by trade .
in order to get water to flow from the garden hose into the house system you would have to overcome the pressure in the house with pressure in the hose.. possible perhaps but I cant; see a likely scenario.. at our summer pace where we pump our own water from a well then perhaps it could happen as we shut the pump down. maybe similar could happen if the city does shut down the house pressure to repair piping or something like that. maybe some unusual situation could cause suction on the city side during city repairs.. for good reason the city is extremely sensitive about is supply being contaminated so this is a precautionary measure and a new law perhaps?
