The tray cable rating applies to the properties of the outer jacket for the individual conductors not the properties of the individual conductors inside. Tray rated cable is obviously intended for use in cable trays. I have 20+years experience in various power plants, up to 1000mw nukes.
Some cable trays can carry hundreds of individual cables, with each cable carrying anywhere up to hundreds of individual conductors. Common instrumentation cable is routinely 14awg with conductors in the teens per cable.
When these cables are initially installed they are probably the most abused they will ever be as they are dragged & stretched. Once installed they must dissipate heat when randomly laid in the tray on top of each other. They must then take the abuse of technicians troubleshooting which can include tools laid/dropped on them, excessive strain to move them out of the way to get to the circuit a tech is looking for, etc. Most importantly they must minimize propagation of fire. Major cable trays are often routed through dedicated "tunnels" that are more heavily protected with automated fire fighting equipment.
Tray rated cable is meant to be more rugged than Romex since it is designed for harsher environments. Generally it will be more expensive than Romex for that reason.
I'm not familiar with a code requirement that forbids installation of tray cable in a residential location but I agree that you should check with your local inspector.
Some cable trays can carry hundreds of individual cables, with each cable carrying anywhere up to hundreds of individual conductors. Common instrumentation cable is routinely 14awg with conductors in the teens per cable.
When these cables are initially installed they are probably the most abused they will ever be as they are dragged & stretched. Once installed they must dissipate heat when randomly laid in the tray on top of each other. They must then take the abuse of technicians troubleshooting which can include tools laid/dropped on them, excessive strain to move them out of the way to get to the circuit a tech is looking for, etc. Most importantly they must minimize propagation of fire. Major cable trays are often routed through dedicated "tunnels" that are more heavily protected with automated fire fighting equipment.
Tray rated cable is meant to be more rugged than Romex since it is designed for harsher environments. Generally it will be more expensive than Romex for that reason.
I'm not familiar with a code requirement that forbids installation of tray cable in a residential location but I agree that you should check with your local inspector.