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Of grounds, electrical wiring and safety practices.

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Computeruser:
I have had five houses in three different states or provinces in two different countries in the space of 7 years. I am still in the fifth house. This has lead to interesting electrical code practices and indeed errors.

The first house was wired with aluminum wiring. It was code at the time; I did not like it; and I moved out (for business reasons) after about 2 years. Now I did have to replace some outlets because the outlets were cheap (still code) and broke down with repeated use. Additionally, I noted that plugging in a toaster and a kettle would blow a fuse. This is not code. So I took out the fuse block for that circuit, went upstairs, stuffed my big screwdriver (plastic handle) across the hot screw and into the box. Big sparks and more fuses go. What was supposed to happen was 3 split outlets into 3 fuse blocks, but the electrician had cross-connected the wires. I have no idea how it passed inspection. Indeed, one wire came from upstairs down into the basement and was not connected. It was cross connected in a light box on the main floor. I had a licenced electrician make repairs and moved on (indeed out, later). But it was a specific lesson that led me to check all wiring in all houses ever after.

We did not stay in the second house long before leaving our native country for the United States. It had two prong outlets (no grounds) but was fundamentally safe if one used safe practices. I did nothing in this house. It is about 60 years old at this point, and code was different at the time it was built.

The third house was new and in Connecticut. Code then (30 years ago) was much the same as Code now. Basic 100 amp service, copper wiring, fuses, and grounded outlets everywhere. No issues, no changes.

The forth house was also new and in New York. It was different in that wire from street to house was aluminum, and wire for the fixed range, heat pump, and electric furnace were also aluminum, but all other wiring was copper. All outlets were ground and I did not make any changes.

The fifth house was (is) back in Canada and where we have lived for 30 years. A quick inspection showed (a) that everything worked properly and (b) the fuse box was a cheap box and fuse blocks would break up when pulled out (checking split outlet kitchen sockets). I quickly engaged a reputable contractor to discard the fuse box and install a Square D circuit breaker box. The wire from the street was code rated at 125 amps, so we put in a 125 amp service. I was informed that special wires with special (expensive insulation) could be installed in the existing conduit from the street to provide code rated 150 amp service, but we have never needed that.

I learned during this work that the refigerator was on the same circuit as the basement lights (code at the time). Again, I found that I could purchase an (expensive) breaker with two 15 amp breakers in one slot. I long ago put the refrigerator on its own ciruit and that is indeed Code practice today. I had some wiring added when we renovated and added an independent Microwave ciruit at the time. I put two 15 amp circuits in my workshop and did some other changes. The bathroom outlets and the outside outlet in on a GFI ciruit which is a good idea, but I often wished there had been two.

So I have learned enough from bad practice and errors to spend the time when purchasing a house to ensure that grounding, wiring and outlets are all completely safe. This is also North American practice and may not apply to you, but whatever applies means hobby work in my electronics workshop will be safe at all times. All five of these homes have 2 live wires coming in from outside and the third (neutral wire) is clamped to earth ground. I have always found this to be desirable.

.... C

alm:

--- Quote from: Computeruser on September 04, 2011, 11:01:12 pm ---So I have learned enough from bad practice and errors to spend the time when purchasing a house to ensure that grounding, wiring and outlets are all completely safe. This is also North American practice and may not apply to you, but whatever applies means hobby work in my electronics workshop will be safe at all times.

--- End quote ---
The assumption is that just because you follow code or take certain precautions it is completely safe is more dangerous than poor wiring with a vigilant attitude, in my opinion. No matter how much time and money you spend, nothing is ever completely safe.

hitachi8:
reminds me of yesterday; i realize that some of my house wall-plug were not installed correctly (inverted polarity), and that some of the light socket were always live.
be sure to always check your house circuit before touching anything, you never know.

IanB:
What alm says is true. Mains electricity is not safe, it is hazardous. It is always wise to respect that hazard.

As for grounding or earthing arrangements you have to go along with the local distribution system. For example in some countries (like the UK) the system earth is usually provided by the electricity company and you are not supposed to make your own earth on the consumer side. It is, however, required that all metal pipework in the house is securely bonded to the system earth.

Computeruser:
To both above - that is why I said I check ALL outlets and wiring upon purchase of a house. Once checked and randomly checked thereafter, it is a reasonable guess that wiring is safe. Children will plug in computers, hair dryers, clocks and whatever. It is ESSENTIAL that wiring be checked and be KNOWN safe. Beyond that, care, of course is required. But I was very clear on that in my post. My attitude is NOT dangerous and NOT vigilante.

Please allow me to remind you of the Normal Distribution in Mathematics (Engineers should know this): Everything, distributed enough times, turns normal.  So when you say "nothing is ever completely safe" - True, but also out in the tiny ends of probability.

Do you grounds check your own outlets before you allow children or guests to plug anything in?

... C

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