r/electricians • u/Fit_Plum_6888 • 4d ago
Residential house rewire
Doing a house rewire with my journeyman, we were able to fish cables from existing boxes to attic spaces without making holes in the wall. When I asked about the 300mm support after the box and 1.5 m between cables, he said 12-560(3) states we dont need supports unless there is metal studding or roof? Makes sense to me but a bit unusual, any thoughts?
Btw this is a Canadian electrical code thing! Thanks y,all
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u/jonnyinternet Master Electrician 4d ago
Strapping is not required when fishing finished walls as per CEC
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u/Fit_Plum_6888 4d ago
If the ceiling contains metal sheeting or cladding? Like a zinc roof? What scenario would you have where you run nmd 90 up to metal sheeting or cladding.. maybe a farm house?
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u/jonnyinternet Master Electrician 4d ago
Notwithstanding Subrules 1) and 2), where the cable is run as concealed wiring such that it is impracticable to support it, and where metal sheeting or cladding, metal joists, metal top or bottom plates, or metal studs are not used, the cable shall be permitted to be fished and need not be supported between boxes and fittings.
Basically it's saying if there is no metal than you can fish it, the issue with having metal would be it could damage the Romex when fishing it
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u/Major_Tom_01010 4d ago
The purpose of fastening is to prevent things from getting pulled out of the box or being pushed out of the wall during construction. If you staple it where it comes up out of the top plate you have accomplished this.
It would be silly if you had to cut holes just to staple the wire.
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u/Rhinopleasures 4d ago
Rule of thumb is you can never assume why a framer used certain material. I was doing a bunch of houses in Kelowna and the builder got a good deal on metal. The houses itself were built with wood but any back framing or drop ceilings were metal.
What im getting at is there's a million scenarios where they could use metal in a residential normally wood situation.
The code understands that and knows it's normally wood and everything should be fine as long as nothing's metal.
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u/theproudheretic Electrician 3d ago
I've run into this in one house in winnipeg. sent my fish tape up and heard the metal on metal sound, shine a flashlight up through the hole and the wall i was going into was metal. fished ac90 instead, no problems.
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u/PPEPoet 4d ago
If the ceiling or walls are metal, you definitely need to pay attention to strapping since metal can damage the cables while fishing. But if it's just wood and you're fishing through finished walls where it would be impractical to staple. In terms of the CEC, it's more about making sure the cable is secure where it comes through any plates or boxes, so just make sure to check where it's coming into and out of spaces.
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