How common are homes without 3-prong grounded outlets in Toronto?

[Eug]

I've only ever lived in relatively new builds, or renovated older properties in Toronto. Every single one of my rentals or owned homes have had 3-prong grounded outlets, and GFI outlets in the bathroom. I've lived in Toronto since the early 90s.

How common is it not to have that?

The reason I ask is because I moved into an area into a 15 year old home that was a tear-down and rebuild of an old bungalow. After I got to know my neighbours, I found out that several of them in the original bungalows (50s) still mostly just have 2-prong outlets, although some of them have a very limited number of 3-prong outlets in very specific areas of the house.

How common is this? How hard is it to retrofit electrical wiring to fully grounded wiring without doing major renovations? All I know is that my friend with knob-and-tube wiring basically had to rip most of her walls apart to update her wiring. However, that's knob-and-tube, in a much older house.

 

[W. K. Lis]

Before the 1950's, it was common to have only 60-amp service and knob-n-tube wiring.

Ground? What ground?

Click on this link for more information.

As well as this link.

 

[Eug]

Thanks, but as I understand it the homes in question don't have knob and tube wiring, yet they're full of 2-pronged outlets. These homes were built in the 50s.

The friend I mentioned with the knob and tube wiring had a much older home. It was a major PITA to retrofit that home with modern wiring.

Would the retrofit of a home with 2-pronged outlets but no knob and tube be as involved as with knob and tube? Or are those homes actually wired with 3-wire runs, and for some reason are just terminated with 2-pronged outlets?

Or am I just completely confused?

 

[cdr108]

does it have copper or aluminum wiring?

isn't the 2-prong vs 3-prong issue more about the socket?

 

[Eug]

does it have copper or aluminum wiring?

Didn't ask.

isn't the 2-prong vs 3-prong issue more about the socket?

That's what I was wondering, especially because it's already 2009, and instead of switching out the sockets, they just limited their 3-prong electonics/appliance usage to specific sockets, or worse, used cheater adapters.

 

[AGTO]

does it have copper or aluminum wiring?

isn't the 2-prong vs 3-prong issue more about the socket?

A 3 conductor socket must have a 3 conductor cable attached to it, otherwise it's just dangerous cosmetics.

 

[Eug]

That was what I was getting at:

These people claim they do not have knob and tube, yet they are stuck with 2-conductor outlets. I assume more of them haven't converted to 3-conductor grounded outlets because it is cost prohibitive to do so. ie. Their wiring doesn't support it, so it would take major work to convert to modern wiring and outlets. I assume this, but don't actually know for a fact.

Doing some Googling, it seems this may make sense. Knob and tube fell out of favour by the 1940s, as by the 50s, plastic sheathed (copper) wiring was available. However, grounded wiring didn't become a requirement until the 1950s, and even then, only for very specific spots in (US) homes. More generalized requirements for grounded wiring didn't become standard until later. As for aluminum wiring, that didn't become popular until the 60s and 70s.

So, it seems to me that these original-bungalow-owning neighbours of mine are stuck in that transition period when fortunately knob and tube wiring was no longer used, but unfortunately, fully grounded 3-wire electrical cabling was not a requirement. Does this sound right?

 

[DJankowski]

I suspect any older homes still featuring 2-prong outlets just didn't drop the cash to replace all their outlets after removing the knob and tube service. However, I have personally seen worse: When my wife and I were house hunting two years ago, we got to tour a two-story detatched built in 1911 that was, according to the realtor, just through a complete renovation, including a new electrical service. Light fixtures had been removed, now showing brand-new three-wire cables ready for use; outlets were replaced with new three-prong versions, including safety versions in bathrooms and the kitchen. Money had been spent to open up the main floor, fix walls, etc. The price was tempting.

That all came to an end once I checked the basement. There was a brand new circuit breaker where the power came into the house, but after tracing some of the modern wiring from it, discovered it went into a separate area of the basement where it was patched into the existing knob and tube wiring. An old lightbulb attached to the k&t still turned on, confirming my suspicions. We had an electrician friend of our realtor double check it, and he discovered the "new" wiring in the second floor only went as far as the first junction box, where it was drawing power from the knob and tube wiring, out of view.

We walked away from the deal. The realtor apparently was fooled by the owners/renovators and ended up dropping them as clients the same day. However, a couple of weeks later, the house was relisted by a different realtor.

 

[Eug]

I suspect any older homes still featuring 2-prong outlets just didn't drop the cash to replace all their outlets after removing the knob and tube service.

Again, AFAIK, these houses were built without knob-and-tube. They were built in the 1950s.

[EDIT]

I just found this Canadian page:

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1910–1950: "Knob and tube"

1950–1962: Ungrounded twin-conductor cable, NMD 1

Twin-conductor cable replaced knob-and tube in early 1950s due to ease of installation. Contained two insulated conductors wrapped in paper and black tar-based cloth casing. Originally contained no ground wire (NMD1), thus the receptacles were not grounded. The insulation temperature rating of this cable was 60°C. Grounded receptacles were not required until 1962.

Risk in modern homes: As with knob-&-tube circuits, original 2-prong ungrounded receptacles have often been exchanged for modern 3-prong receptacles, giving false impression of ground protection. This is an easy check and an easy repair. Ground-fault circuit interruption (GFCI) receptacles or breakers can be installed, providing 3-prong receptacles with ground protection.

----

This makes sense in the context of these homes. So, basically, when you're looking at a home in the post knob-and-tube era, you still have the problem of ungrounded 2-conductor wiring, unless the home was built or renovated after the early 1960s.

Also from that page: In the mid-60s and 70s everything was grounded, but many used aluminum wiring, which potentially brings a different set of issues, especially if the wiring hasn't been inspected recently. Furthermore, grounded wiring from that era was only rated to 60 degrees Celcius, and that is a fire hazard in certain usage (like recessed lighting). And then post 70s, you still have the issues of DIY wiring, which often is done incorrectly.

The interesting thing from that page is that it suggests that GFCI 3-prong outlets can be used in these 50s homes with 2-conductor wiring, but it makes no mention of that for knob and tube wiring. I don't understand why there is a difference here, but if that's true, that would make them much, much easier to upgrade than knob and tube. Sure, each outlet is 10 bucks, but that's a heluvalot better than ripping your walls apart.

 

[paraone]

Don't be too concerned. I just bought a new place that had quite a bit of knob and tube, two bedrooms, the living room, dining room all over head fixtures, a porch light and a basement light were all on knob and tube. It's being replaced right now, will take 3-4 days and is costing $2400, that including having 6 pot lights installed in the living room. I am saving some money by doing the patch work myself, but it's really minimal.
Knob and tube is actually harder to replace than the twin conductor cable your referring to. Basically they have to fish new wiring everywhere, with existing conventional covered wiring, the can "pull" alot of the wires, meaning they disconnect the old, tie the new onto that and pull the old wire out thus fishing the new wire in the process, this saves a bit of $$$$

Either way don't freak out, not a huge job and no, they don't have to destroy your home to do it. Let me know if you need a number.

 

[cdr108]

We walked away from the deal. The realtor apparently was fooled by the owners/renovators and ended up dropping them as clients the same day. However, a couple of weeks later, the house was relisted by a different realtor.

when i hear something like that, i think it's the duty of the realtor and CREA to red-flag the property/listing as having K&T if they know it, instead of passing the buck to the next realtor and unsuspecting buyer.

it is fraud to advertise a complete renovation with new electrical service, yet only done some to hide the fact that it was not done.

 

[Eug]

Don't be too concerned. I just bought a new place that had quite a bit of knob and tube, two bedrooms, the living room, dining room all over head fixtures, a porch light and a basement light were all on knob and tube. It's being replaced right now, will take 3-4 days and is costing $2400, that including having 6 pot lights installed in the living room. I am saving some money by doing the patch work myself, but it's really minimal.

--

Either way don't freak out, not a huge job and no, they don't have to destroy your home to do it. Let me know if you need a number.

Thanks, but it was just for my own information. I just didn't understand why my neighbours were in this odd situation I don't hear much about in Toronto: No knob-and-tube, but restricted to 2-prong outlets. Now I know. And if that GFCI advice is accurate, then getting protected outlets is not such a big deal, since you can just change the outlets (albeit at $10 per receptacle just for the outlet).

However, I will say my friend who had knob and tube replaced spent over $20000 to get the house rewired, and it took many weeks. (However, it was a big house, and the whole house was knob and tube.)

My house was actually built in the mid 90s, with an addition less than 10 years ago, so I actually have the most up to date wiring.

Knob and tube is actually harder to replace than the twin conductor cable your referring to. Basically they have to fish new wiring everywhere, with existing conventional covered wiring, the can "pull" alot of the wires, meaning they disconnect the old, tie the new onto that and pull the old wire out thus fishing the new wire in the process, this saves a bit of $$$$

Hmmm. That seems optimistic. My (very superficial) understanding is that much of the wire is anchored down in a lot of areas, so fishing is very problematic. It's not like pulling CAT5e network cable that exists within conduits.

when i hear something like that, i think it's the duty of the realtor and CREA to red-flag the property/listing as having K&T if they know it, instead of passing the buck to the next realtor and unsuspecting buyer.

it is fraud to advertise a complete renovation with new electrical service, yet only done some to hide the fact that it was not done.

Agreed, but if I were ever to buy a house of that age, I think for the inspection I'd hire a plumber to snake the pipes and an electrician to check the wiring.

 

[Eug]

Thanks, but it was just for my own information. I just didn't understand why my neighbours were in this odd situation I don't hear much about in Toronto: No knob-and-tube, but restricted to 2-prong outlets. Now I know. And if that GFCI advice is accurate, then getting protected outlets is not such a big deal, since you can just change the outlets (albeit at $10 per receptacle just for the outlet).

Hmmm... Further reading suggests even that is not necessary.

Assuming you don't want to use GFCI breakers, you can simply use one GFCI outlet per circuit. So, if you have a circuit with 3 outlets, you use one GFCI outlet, and the other two outlets can be wired with the usual non-GFCI 3-prong outlets.

Nice. I should tell my neighbours to consult an electrician. Perhaps they can get a whole bunch of properly protected 3-prong outlets for just hundreds instead of thousands like it would cost for knob-and-tube.

 

[paraone]

Thanks, but it was just for my own information. I just didn't understand why my neighbours were in this odd situation I don't hear much about in Toronto: No knob-and-tube, but restricted to 2-prong outlets. Now I know. And if that GFCI advice is accurate, then getting protected outlets is not such a big deal, since you can just change the outlets (albeit at $10 per receptacle just for the outlet).

Yes I believe that to correct as well, you can add a GFI breaker and outlet and ground the circuit.

However, I will say my friend who had knob and tube replaced spent over $20000 to get the house rewired, and it took many weeks. (However, it was a big house, and the whole house was knob and tube.)

it does vary, our place is 1800 sqft, and again I'd say that we are rewiring about 40% of the house. Also many other things have to be considered, we aren't adding many new lights or circuits or new outlets, we are simply rewiring what exists. Also by doing the drywall myself I've saved about $800-1600 dollars.

Hmmm. That seems optimistic. My (very superficial) understanding is that much of the wire is anchored down in a lot of areas, so fishing is very problematic. It's not like pulling CAT5e network cable that exists within conduits.

Actually it is alot like running CAT5e, yes the wire is anchored down in places, normally at a change of direction or vertical run, but normally it's just treaded through the studs for a horizontal run. Again you do have to punch holes in the wall but nothing that would require you to replace the entire wall, unless of course it is old paster.

 

[AGTO]

Ground-fault circuit interruption (GFCI) receptacles or breakers can be installed, providing 3-prong receptacles with ground protection.

This is incorrect, GFCI breakers do not create a ground out of nothing.

Yes I believe that to correct as well, you can add a GFI breaker and outlet and ground the circuit

A GFCI outlet or breaker DOES NOT ground the circuit or provide a safety ground.

Perhaps they can get a whole bunch of properly protected 3-prong outlets for just hundreds instead of thousands like it would cost for knob-and-tube.

No.

A GFCI device monitors the current flowing through the hot and neutral wires to the load, and imbalance in this current indicates a third path for current to flow. This is the result of a fault in the load. The GFCI breaker trips when this is detected to prevent electrocution....since there IS NO safety ground present.