Cables through concrete block wall


Old 12-26-17, 03:12 PM
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Post Cables through concrete block wall

I want to pass two (or maybe three) new circuits through a concrete block wall, from the garage where the panel is, into the house to connect a new oven and stovetop. The oven and stovetop circuits each need to handle 40A, so 8/3 wire. While Im at it, Im considering adding the third circuit to provide a split receptacle in my workshop. That circuit would enter the house at the same place.

The wires from the panel will come down the block wall from the garage ceiling, and then go horizontally through that wall into the house. There is already one such cable servicing an air conditioner installed some years ago, photo attached. Id like to follow more or less the same route with my new cables. (Photo attached.)

What I'm wondering is...

1. Can I just enlarge the hole already in place for the existing cable and pass three new cables through it, in conduit like the existing cable?
If so, must the conduit/s continue all the way through the block wall?

- not too sure I like the idea of trying to enlarge the existing hole without damaging the cable already in place -

2. Or should I make a new hole through the wall, some inches away from existing cable, with perhaps a large conduit through the wall,and pass the new cables through that conduit? (Rough sketch attached) Plug the air space in the conduit with insulation and seal up the vapour barrier as much as possible.

I see elsewhere on this forum () the suggestion that a box be mounted where the wires exit into the garage, which seems a good idea. (Thank you, Tolyn!) If I do this, what size conduit is needed in the wall?

It seems to me that this option (#2) would give me the flexibility of adding the third circuit at a later time, rather than now.

I expect it would be easier to cut the wires and connect them in the box rather than try to pull them all the way through....

Many thanks for any thoughts!
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