Conduit and masonry ceiling

zubor

I am rewiring the lighting in a part of my basement which was an addition to the house and has a masonry ceiling. It seems as if they laid conduit in the masonry, but it is impossible to find the opening without some serious demolition I am not willing to do.

As an alternative, I would like to run some conduit along the surface of the ceiling. I have never worked with conduit before. I would be running nmd90 romex, so this would be just for mechanical protection. I will use fluorescent fixtures with integrated junction boxes to make the connections.

Any suggestions on type of conduit, what is required for entrance/exit of the cable into the conduit, etc? Sorry for such a broad question... just looking for a place to start.

Thanks!

Julius793

Go with PVC quite easy to install.

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zubor

I was thinking about PVC, but am worried about having to bend it where it comes off the ceiling to enter a box/light.

I am using fluorescent wraps where the 1/2" knockout on the ends is not right at the top (ceiling side) of the light.

Any thoughts?

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Julius793

Well get a hole-saw and make a knockout where you need it, goin to be a lot easier that bending an exact off-set. And PVC is quite flexible so if it's a drop off it won't be an issue.

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zubor

I could do that!!!

What is the proper way to connect the conduit to the 1/2" knockout and clamp the NM cable inside as it exits the conduit into the fixture?

Are there any requirements for the point of entry of NM cable into the conduit?

joed

What kind of protection do yo need on a ceiling? Just run the NMD90.

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zubor

It is > 1.5 m above the floor so exempt from 12-518 in the CEC.

I guess it's just piece of mind... high traffic area that I carry lots of equipment through and the ceiling is only 6.5 ft high

andrew79

Use bx and clip it nice

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zubor

Then I need to run BX all the way from the panel, or transition from NM to BX in a box somewhere.

From the panel most of the way to the light it is wooded joists. It's only a small addition at the very end of the run where the cable needs protection.

andrew79

You can run right from the panel or transition wherever you like in a box.

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I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.

Evstarr

Use minerelac (sp?) hangers and run the pipe in a straight line into the ko. No offset needed as the pipe will be off the surface by the right amount already.