[sirsparksalot]

Should the plastic knockouts (correct term?) be completely removed, or should they be used to hold the cable? My concern is that the tabs are very strong (it seems) and might damage the outer sheath of NM.

 

[AllanJ]

Those tabs stay in place to hold the cables.

 

[Jim Port]

Only the knockouts in the single gang boxes are removed.

In the type boxes shown those are clamps and not removed. You just push the cable thru. They do not damage the cable.

 

[frenchelectrican]

Those two box you posted in the photo the K.O tabs are not removeable but just push the cable in I Know it will be hard at first but once the cable in the place it is not a issue.

even single gang old work box have same pattern as you show the photo the new work box do not have that type of hold in clip like that just punch it out.

Just beaware two things .,

• wire capicity fill. just don't overfull the box

• old work round box if you mount them on wall or ceiling they are limited to about 3 KG or 6 pounds anything hevier than that get a old work ceiling fan box they will have expandable spanner to lock to the studs otherwise a pancake box will work if you hit the stud.

Merci,
Marc