jar546
Forum Coordinator
There are exceptions to every rule, and this section has two exceptions. I encourage you to read this short code section before your next inspection. Here is what it means.
When you're dealing with cables, pipes (raceways), or boxes under a roof made of metal-corrugated sheets, there's a specific way they need to be installed. You've got to make sure there's a gap of at least 1½ inches between the bottom of the roof decking and the top of whatever you're installing. This space is crucial.
Why the gap? Well, when roofs get repaired or replaced, workers often use long screws or similar tools that can pierce through the roof material. If your cables or raceways are too close to the roof, they could get damaged by these screws. That's a risk you don't want to take, both for safety and functionality.
However, there are a couple of exceptions to this rule. First, if you're using rigid metal conduits or intermediate metal conduits with the right fittings and boxes, you don't have to worry about this 1½-inch gap rule. These materials are tough enough to handle potential screw penetration.
Second, if the metal roof is covered with a concrete slab that's at least 2 inches thick, you also don't need to maintain this gap. The concrete provides enough protection.
This rule is kind of like making sure you don't build a shed too close to a tree. If the tree's branches grow, they could damage the shed. Similarly, if you don't leave enough space between the roof and your installations, future roofing work could damage your electrical setup.
It’s all about thinking ahead and preventing potential issues down the road. Just like how you'd plan a building project with future maintenance in mind, electrical installations need the same foresight, especially under something as variable as a roof.
When you're dealing with cables, pipes (raceways), or boxes under a roof made of metal-corrugated sheets, there's a specific way they need to be installed. You've got to make sure there's a gap of at least 1½ inches between the bottom of the roof decking and the top of whatever you're installing. This space is crucial.
Why the gap? Well, when roofs get repaired or replaced, workers often use long screws or similar tools that can pierce through the roof material. If your cables or raceways are too close to the roof, they could get damaged by these screws. That's a risk you don't want to take, both for safety and functionality.
However, there are a couple of exceptions to this rule. First, if you're using rigid metal conduits or intermediate metal conduits with the right fittings and boxes, you don't have to worry about this 1½-inch gap rule. These materials are tough enough to handle potential screw penetration.
Second, if the metal roof is covered with a concrete slab that's at least 2 inches thick, you also don't need to maintain this gap. The concrete provides enough protection.
This rule is kind of like making sure you don't build a shed too close to a tree. If the tree's branches grow, they could damage the shed. Similarly, if you don't leave enough space between the roof and your installations, future roofing work could damage your electrical setup.
It’s all about thinking ahead and preventing potential issues down the road. Just like how you'd plan a building project with future maintenance in mind, electrical installations need the same foresight, especially under something as variable as a roof.