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Discussion Starter · #1 ·
Hello, I am a newbie to this forum.
I spent a lot of time online trying to find an answer and thought this forum might be the best place.

Trying to install a ceiling fan in a ~1900 house. Knob and post still used in some places.

There is no no ground wire. There are two black wires coming out of the ceiling. How do I tell which is hot?

Would running a wire to the copper pipes under the sink in the other room to use as a ground work so I could test with a multimeter?

Any other suggestions? Thanks for any help.
 

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Hello, I am a newbie to this forum.
I spent a lot of time online trying to find an answer and thought this forum might be the best place.

Trying to install a ceiling fan in a ~1900 house. Knob and post still used in some places.

There is no no ground wire. There are two black wires coming out of the ceiling. How do I tell which is hot?

Would running a wire to the copper pipes under the sink in the other room to use as a ground work so I could test with a multimeter?

Any other suggestions? Thanks for any help.

You need to use a non-contact voltage tester, and when placed near a wire, it will beep continuously if the wire is hot. That is the hot wire. The other wire is neutral. But if the house and wiring are that old, then you have more serious electrical issues. Knob & tube wire is not safe anymore, given its age, and it is likely to deteriorate and cause a fire. Also, fans cannot be installed onto existing fixture boxes; they must be replaced with a fan-rated box.
 

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Discussion Starter · #5 · (Edited)
Bluegrassguy:Thanks for this info. Tester ordered.

Labradors: I believe so - would need to check.



Joed - only been here (just relocated) 4 days and have yet top see a grounded receptacle etc. The original wiring seems to be in place still but some not used and some is. I think most of the wiring in the house has been updated - but again - no receptacles with a ground.



I saw a video about an external ceiling fan mounting block that is screwed directly into a ceiling joist.


I admit I have not seen this before - does anyone know. if this is a legit option?
 

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....have yet top see a grounded receptacle etc. The original wiring seems to be in place still but some not used and some is. I think most of the wiring in the house has been updated - but again - no receptacles with a ground.
Old knob and tube isn't really the hazard in itself. It's when it's been modified, added to, worked around, insulated on top of, etc that it becomes an issue. Chances are all of the above have happened since 1900 so if it's at all feasible to rewire the house at this point, I'd do it.
The advantages besides not burning down in the middle of the night are that you'll be able to have grounded receptacles that are actually grounded, you can add receptacles, upgrade service to places like the kitchen, laundry, mechanicals, garage, and you'll probably get a lower insurance rate once it's rewired. After it's rewired you'll also then be able to insulate your walls and attic.
 

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Discussion Starter · #8 ·
Well it would not be the first old ~1900 house I have rewired...just the second :biggrin2:
I went down and looked at the wiring again. My guess is that some of the harder things to get to were left alone. This ceiling fan I want to install would be a hard thing to rewire since its the ceiling of the first floor, lath and plaster etc.



I had to take down the chandelier while in the process of unpacking b/c I kept hitting my head on it. So I thought I would put up a fan while I was at it. Will rewire when I can.



Does anyone know if that video showing the ceiling fan mounting block would be a legit way for now?
 

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Your mileage may vary so proceed with caution.


While they are not 'fan rated' most old pre 1950 ceiling boxes are more than adequately supported to handle up to a 52" standard ceiling fan. Before they invented the modern hanger bar design the old sparky often used scraps of 2x4 or 1x4 to create a bridge between the joists and screw the box to it. If it was simply nailed to the bridge add a couple of screws.

Edit: Calibrate your non contact test to avoid false positives by adjusting it on a live outlet. It should sound off on the hot side and not sound off on the neutral side of an outlet. Do this every time you use it.
Also note that with K&T when turning off a single breaker there may still be current on the neutral side due to shared commons.


I have installed them this way multiple times.


There is also the option of using a hugger style bracket which does not rely on the box for support.
 

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" An electrical snake wire".... gezz I hate snakes. Now I'll never want to touch my two Greenlee fish tapes again. :smile:


Lot of people may not think about this, but KT as long as was installed properly and has not been tapped on to improperly or mutilated, was a really safe wiring system in its day.

With the KT conductors OC protection being most times the old Type S screw- in glass top fuses, any overcurrent situations were covered well and dependable, with the Type S fuse's melting solder links. Short to ground/ fault protection ? Hmmm. not so much. :) .

I re-wired a lot of the early 1900's houses back in the day that had KT. And not one of them was because of a electrical fire caused from the KT though. And IMO, KT was good in its day because the KT conductors never touched wood.

Unlike the two more modern homes that I did service work on where the abuse of the electrical cable caused a fire. In one home, someone pulled a Type SE for a range cable 50 ft, across an attic. When it came over the last ceiling joist, apparently it was a inch too short for the installer.

So the wire puller put all their weight on as it came down through the top plates and then stapled it tight. The cable was as tight as a fiddle string across all the attic joists.

So over time, the sharp edge of the top of the joist at the wall's top plate from the homes slight movement over the passed 40 years, cut in to the cable. While exposing some of the hot copper strands to the wrapped neutral stranded conductors in the SE cable, making them arc and ignition followed.

And another electrical fire I was called to, was where a kitchen soffit had the 7 in. recess can lights installed in it. And one of the can lights had its 3/8" Romex cable connector screws on the cable so TIGHT where it entered the RC light's J-Box, it finally cut through the cables conductors and sparked, setting the soffit space on fire.

Neither event would have happened...with KT wiring IMO. But we all know that we have better wiring cables in our homes now. As long as they do not get the abuse, as the ones in my post here had done to them. JMO.
 

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Discussion Starter · #11 ·
Thanks for all the great info! I figured the current system as it is would support the weight b/c of the way it was made. I will do a bit more exploratory "surgery" to see exactly how the ceiling above where the fan would be installed is put together.



I just want to make sure I am getting this right. As it sits, the wiring is likely OK to use as the exposed areas still seem to have good insulation on them. As long as I make sure the "hardware" above the ceiling where the fan hanging bracket is mounted to, then I am assuming its OK to mount without worrying about replacing the old box with one specifically said to be for a fan? It seems to me that would almost be self defeating ("if it ain't broke, don't fix it!). Or would this mean if there ever was a fire that the insurance company would be able to weasel out on their responsibilities?
 
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