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Old Home Wiring
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Since early on when electricity started to be used it has been a learning process for this industry which still continuous even today. Unfortunately that learning process has come over the years with a heavy price and through fires and tragedies we have learned to better prevent accidents & tragedies and the industry continually comes up with new ways to make electricity even safer to use.
Wiring practices / methods used today better protect us from electrical accidents / tragedies than the standards where years ago, yet years ago the standards at that time where thought to be safe but considered unsafe by today's standards, as mentioned that lesson has unfortunately been learned the hard way.
Most jurisdictions do not force you to update old wiring, unless it actually was declared condemned but any new electrical work must meet the current codes.
I know an elderly couple living in a very old home, they are both retired and since the husband grew up in Jamaica, they also have a home in Jamaica where every year they go and get out of the Canadian winters and go to Jamaica and then return to Canada for the warmer months, and we check up the home here while they are gone.
One year we thought we would surprise them and resurface the hardwood floor and repaint the walls, then we realized issues with the electrical wiring. First ungrounded electrical outlets, next when I plugged something into the outlet the plug would not stay but fall out and you had to put something under the cord to prevent it from falling out of the outlet socket. Some light switches you could see flashes from arcing when switched on or off. All this was something that gave me a big uneasy feeling about the electrical safety in that home. I did not feel even safe to plug in a rental hard floor sander into any electrical outlet there. It was my feeling the whole home should have been rewired, but since I was not prepared to pay to have someone else's home rewired, and I knew the elderly couple would not have done it, I thought on how I could make it safer perhaps not safest but at least safer, safest would be re-wiring top to bottom, the home in my view was a fire waiting to happen. Safer meant changing every light switch and every outlet in the home, and grounding outlets, checking polarity on so on.
So with the help of a friend, I bought enough brand new modern day outlets, light switches, even new light fixtures and lots of green 14 gage rolls of wire, what I found as we open all the outlet / fixture / switch boxes you could literally see the history of the home and realize that the home had been wired in stages, with different types of wiring, I suspect the home electrical was added on as the home was expanded to new additions. 3 way switches had all wires identical in color.
So armed with a multi meter (shutting done the electrical at times to the entire home, other times just individual circuits), I found some electrical boxes had a grounding connection but others did not. Even though the wires where most often not coloured, but using the multi meter I was able to figure out which wire was the grounded conductor (neutral), and which one was the ungrounded conductor (hot), and also was able to check on the existence of a electrical box ground. It would have been a nightmare to open walls up to run new wires something I was not going to get into. But we ran green wires and in instances where we could not drill through the inside into the basement, we would run it along the edge of the baseboards and drilled a small hole to get the wire into the basement, not sure if that method would have met code but the aim was to make it safer but not necessarily safest in hopes of avoiding a fire waiting to happen. Some switch boxes we where not able to ground as these where not near the floor, but the switches where replaced. One wire at a ceiling fixture had wires so brittle that the insulation was breaking off as you touched it, although it crossed my mind I decided not to open the ceiling up to replace the wire cable but to carefully use electrical tape around the brittle exposed area and was careful not to work the wire any more than needed in installing a new fixture.
We bought some electrical pipe grounding clamps and grounded everything to metal water pipes in the basement, in some jurisdictions it is allowed to ground to a metal water pipe, in other jurisdictions it is not allowed.
I would like to say even after that was all done I still would have felt better if all the wiring was replaced, but at least I was comfortable to say that it was safer and we may have just prevented a tragedy. We also added two battery operated smoke detectors to the home where it previously had none, and replaced the upstairs bathroom outlet with a GFI outlet.
Two or three years later, a unfortunate incident happen to the home of this same couple in which the furnace failed while they where spending the winter in Jamaica and the heater radiators busted and the resultant freeze up did expensive damage to the home, fortunately insurance covered everything, so it was a hidden blessing in a way as the home was gutted by the restorer, removed some asbestos that they discovered as well as re-wired the entire home top to bottom now the wiring is as I referred to safest.
If you have bought a really old home, it may be built like a mac truck as they say, but unless the wiring has been updated it will not be to today's safety standards and not likely grounded, if the outlet has only a 2 prong then it is not a grounded outlet. Some electrical codes allow the use of a GFI to give some protection to an ungrounded outlet, in these cases a label must be placed on the outlet indicating it is not grounded. My preference is to not do work a around but to have the outlets properly grounded.
My preference is to not mess around and if you are able to then re-wire to today's standards but if you cannot afford re-wiring the whole home, then at least....
a) Replace ALL outlets with modern grounded outlets, running ground wires as required.
b) Replace ALL light switches
c) Replace all light fixtures.
d) check with the electrical authority in charge of your area to find out the acceptable routing of grounding wires and rather grounding to metal water pipes is allowed in your jurisdiction.
e) Because of the age of the wiring I would recommend using only 15 amp fuses / breakers for general purpose circuits even if the wire gage is rated for 20 amps.
f) when connecting wires that cannot be identified, in fact with older wiring I would check anyway, use a multi meter to to identify (or an outlet tester) which wire is the ungrounded conductor (hot) and which wire is the grounded conductor (neutral), I will go into more details on how to identify these wires in an article on a sister website, see links to current and future websites on the main page of this website. If using an outlet tester, the indicator lights will tell if it is wired correctly, and if not which wires are incorrect.
Fortunately the very old homes will not likely have aluminium wiring concerns as that was introduced I believe in the mid 1960's.
Written: Jan. 16. 2012
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Donald Kerr / Wiring Done Right