Commercial wiring question

[Marc Voorhees]

I am helping some friends rewire some lights in a commercial space in a basement. The building was built in 1908 and electrified after that. Currently, the wiring going to the lights is bx cable without a ground, but it is in the floor joists in the ceiling (in drilled holes in the joists). There need to be some changes to a few crcuits like removing the plugs from the same circuit as the lights. They want to have an exposed ceiling, so I am planning on using the existing holes in the joists and drill additional ones as needed. Outlets will have emt conduit down the wall to the boxes
I don't want to use the existing either sure to grounding issues and wanting to upgrade everything anyway.


My question is this: in a commercial application, can I run romex in the joists as I would in a residential application? Or do I need to run bx with a ground through the existing holes? Or something. Else? I just want to make sure I only do this once. I hope this is enough I formation to answer this question

We are in Michigan, we are using some exceptions to the nec (for example, no afci requirements). But any guidance would be great.

Thank you all in advance!

 

[loganb]

This is a question for the authority having jurisdiction (AHJ). Use of the building and circuit load may impact things as well, but you need to start with the inspecting agency's website and review the local codes which are generally available on the building depts website.

 

[wyliesdiesels]

NM-b is permitted in commercial spaces except above drop ceilings... check with AHJ if they have local WRITTEN amendments

 

[Marc Voorhees]

NM-b is permitted in commercial spaces except above drop ceilings... check with AHJ if they have local WRITTEN amendments

Thank you!!!!

 

[TRWham]

If it’s really AC (aka BX) and not MC then the armor is the EGC if it’s terminated correctly.

 

[Marc Voorhees]

If it’s really AC (aka BX) and not MC then the armor is the EGC if it’s terminated correctly.

Yes, this is correct. I am unsure if it is done right throughout the whole layout. As an example, none of the three prong plugs that are currently installed have any ground wires. Almost all of the plugs spark heavily if you plug something into them, and I genuinely would prefer to start fresh with the wiring in some places, And if I go that route, personally, I prefer having a ground wire rather than using the armor as a ground.

I suppose I could reuse the bx that is there and just ensure it it installed properly if i needed

Also, given the age of the work, I genuinely don't k ow if this bx has a bonding strip in it

 

[TRWham]

I wouldn't argue with your assessment. You might be able to skip a step and pull all new wire into the BX already in place if there is room in the armor to add the EGC. As for NM in a "commercial" building, it is generally accepted in class III, IV and V structures but that will vary by location and, no matter how correct and safe, exposed NM may look out of place depending on how the space is to be used and how they want it to look.

 

[Terry D]

There are 5 classes of building construction. It all has to do with the fire rating of the building. NM is not allowed in class I and class II structures unless installed in raceways that are permitted to be install in class I and II construction

 

[Terry D]

I wouldn't argue with your assessment. You might be able to skip a step and pull all new wire into the BX already in place if there is room in the armor to add the EGC. As for NM in a "commercial" building, it is generally accepted in class III, IV and V structures but that will vary by location and, no matter how correct and safe, exposed NM may look out of place depending on how the space is to be used and how they want it to look.

I don't see anyway possible to remove and pull new wire into BX cable. Even if you could, it would not be permitted. You would have to treat it as FMC, and anything under 1/2" is not permitted for building wiring. It is manufactured as a cable assembly

 

[Marc Voorhees]

I don't see anyway possible to remove and pull new wire into BX cable. Even if you could, it would not be permitted. You would have to treat it as FMC, and anything under 1/2" is not permitted for building wiring. It is manufactured as a cable assembly

Yeah, not going to try this one.

I think I am just going to use new bx and do the correct bonding. The nm would look out of place for sure even if it is"right" in an application

 

[Terry D]

Yeah, not going to try this one.

I think I am just going to use new bx and do the correct bonding. The nm would look out of place for sure even if it is"right" in an application

Use MC cable, it has the ground in it.

 

[Marc Voorhees]

Use MC cable, it has the ground in it.

Makes even more sense

 

[Terry D]

The also make a MC cable without a actual EGC, cant remember the name of it. It has a purple strip on the outer jacket. When used with the approved connectors, it eliminates the need for a EGC. But it costs more

 

[rlitman]

If it’s really AC (aka BX) and not MC then the armor is the EGC if it’s terminated correctly.

I've got some real BX (FYI, BX is a brans name, whereas AC is an NEC designation) in my house from 1929. BX has cloth covered rubber insulation, and NO aluminum grounding wire. Whenever you have the opportunity to replace BX, take it!

AC in stores today has modern insulation and an aluminum bonding wire that lowers the ground resistance of the armor. I wouldn't buy AC any more, but I've used a lot of it over the years. It's fine.

If you're buying wire today, consider MC-Lite. The aluminum armor cuts the weight of the cable significantly. It's MUCH easier to work with.

 

[Marc Voorhees]

I've got some real BX (FYI, BX is a brans name, whereas AC is an NEC designation) in my house from 1929. BX has cloth covered rubber insulation, and NO aluminum grounding wire. Whenever you have the opportunity to replace BX, take it!

AC in stores today has modern insulation and an aluminum bonding wire that lowers the ground resistance of the armor. I wouldn't buy AC any more, but I've used a lot of it over the years. It's fine.

If you're buying wire today, consider MC-Lite. The aluminum armor cuts the weight of the cable significantly. It's MUCH easier to work with.

This is what I was planning on using

https://www.lowes.com/pd/Southwire-Armorlite-250-ft-12-2-Solid-Aluminum-MC-Cable/50189129

 

[TRWham]

I don't see anyway possible to remove and pull new wire into BX cable. Even if you could, it would not be permitted. You would have to treat it as FMC, and anything under 1/2" is not permitted for building wiring. It is manufactured as a cable assembly

That's what I was thinking might work (armor as FMC) but I don't know what size the armor is or how long the runs are. If in doubt, pull it out and start over.

 

[Marc Voorhees]

If in doubt, pull it out

This motto got me through college and I think it will get me through this project as well

 

[TRWham]

This motto got me through college and I think it will get me through this project as well

GJ never lets me down where double entendres is concerned.