Old rewiring job

[Eddie702]

Ran into a few issues rewiring a 100-year-old house.

Just out of curiosity has anyone run into old BX that had like a brass or copper sleeve about 3/4" long installed over the end of the BX where the box clamp clamped the BX? Probably there to help improve the ground I assume.

I figured out today when this place was originally wired it had like 1-2 receptacles in each room and a pull chain light in the ceiling.

Most of the device boxes are typical old work boxes screwed/nailed to the lath, guess they didn't make boxes with side brackets to attach to the studs back in the day. These had the box ears on top of the plaster and they screwed through the plaster and into the lath. No problem with those

Most are only 2 1/2" deep so box fill is an issue. Usually just pull 1 Romex down to the basement and J box it as the box fill won't allow daisy chain. Plus most of the interior walls are 2 x 3 studs so a 3" deep box is as large as you can go. Trying not to chop too much plaster

These were pretty easy, tie a string to the BX and pull it down to the basement, ty the Romex on and pull it up. No staples on the BX in the walls.

You know your into the old stuff when the BX is secured in the basement with 2 6d nails bent over the BX in opposite directions. Guess they didn't have staples back then.

But then I ran into some of the original device boxes. These boxes don't have the "flat bottom" pry outs like the newer boxes. You pull the bx out and you can't use Romex because the old bx ko has a sharp edge that will cut into the Romex.

So I guess I have 2 choices. Chop the plaster out and put in a Romex box. I did two boxes like this and it makes a mess that I have to patch and paint. They actually screwed the box ears to the lath and plastered over the lath and the box ears so you have to cut the plaster out to change the box and becomes a mess.

So tomorrow I am going to try leaving the old boxes in place and I picked up some BX to get out of the box and get to the next box in the cellar. Problem is I have to try and get some of the pry outs out of the old boxes which won't be easy. The old boxes have no 1/2" KOs so can't use a connector.

I have a tiny 90 deg angle attachment for my drill. I am hoping it will be small enough to fit in the box and drill a sheet metal screw through the BX Ko and pry it out. If not I will have a lot of patching.

 

[tortuga]

So I guess I have 2 choices. Chop the plaster out and put in a Romex box. I did two boxes like this and it makes a mess that I have to patch and paint. They actually screwed the box ears to the lath and plastered over the lath and the box ears so you have to cut the plaster out to change the box and becomes a mess.

Old lathe and plaster house rewiring in finished home a real art, its been a while since I did one, I typically go the route of cutting in new boxes, those plastic 'slider' or 'smart' boxes that mount to a stud. The fragile old plaster and lathe is a challenge, some I have had to make a deep score in the plaster with a knife then carefully chip out the plaster, finally I cut the lathe with a drywallers 'roto zip' tool careful not to hit the plaster for which the penalty is a instantly dull blade. A plaster guy told me to use that tool many years ago. He said the plaster forms hooks thru the lathe and once those hooks break off inside the wall the plaster starts to fail.
Most people just sheet over it with sheetrock, or gut the house then its easy.
Other tools like sawzall /oscillating tool I have not had tons of luck with on lathe, unless the lathe is in really good shape they vibrate the wall too much and loosen the plaster. I have seen a carpenter that did some trick with a really small cordless saw or angle grinder, I want to say he had a old wood blade on backwards not sure, but he had it down.
Best of luck and wear a mask, that dust is rough,

 

[hbiss]

Most of the device boxes are typical old work boxes screwed/nailed to the lath, guess they didn't make boxes with side brackets to attach to the studs back in the day. These had the box ears on top of the plaster and they screwed through the plaster and into the lath.

I have a house that is a modular, built in 1989. It has plastic boxes with ears that are screwed to what looks like scrap 1x2 material top and bottom on the inside of the sheetrock. I assume the wood strips are screwed through the sheetrock to hold them in place. In most locations NM is fished down from the top. Trying to understand why they would do something like that. I'm waiting for a reason to cut a section of sheetrock out so I can see what they did.

-Hal

 

[don_resqcapt19]

I have a house that is a modular, built in 1989. It has plastic boxes with ears that are screwed to what looks like scrap 1x2 material top and bottom on the inside of the sheetrock. I assume the wood strips are screwed through the sheetrock to hold them in place. In most locations NM is fished down from the top. Trying to understand why they would do something like that. I'm waiting for a reason to cut a section of sheetrock out so I can see what they did.

-Hal

For cutting boxes into existing walls, that provides better support than most any other method, unless you can screw the box to a stud. No idea why that would ever be used for new construction, unless a box was missed at rough in.

 

[tortuga]

Residential rewiring of say pre 1940's housing is a underrated under appreciated skill, I worked for years with a semi retired residential electrician who could read a old house the way a good fisherman reads a lake and just knows a good fishing spot. He could guess how knob and tube was routed. He had a trick for everything, and knew how they were framed and stuff the framers did like angle blocking.

 

[hbiss]

For cutting boxes into existing walls, that provides better support than most any other method, unless you can screw the box to a stud. No idea why that would ever be used for new construction, unless a box was missed at rough in.

Sure, done it myself. But here it was like they built the partitions, rocked them then brought them over to the floor platform and screwed them down. Then they did the ceiling joists. Before they did the roof framing, somebody got up on a step ladder, drilled holes and dropped all the wiring. Then they came around and cut-in all the boxes. For some reason they even put 1/2" EMT sleeves in the off-center top plate holes- maybe so nails wouldn't damage the cable if they installed crown molding? Trying to visualize building this thing inside an aircraft hangar.

Dunno, I've worked on modulars before but never saw anything like this.

-Hal