Exposed Run (ER) rated tray cable (type TC-ER) consists of insulated conductors bundled together with binder tape and covered with a jacket. The design of ER tray cable provides extra durability, allowing it to be run or dropped longer distances without the support of cable tray, raceway, or conduit.
BENEFITS OF ER RATED TRAY CABLE
ER tray cable offers a number of practical benefits for contractors.
- Faster Installation: cables can drop up to six feet directly from cable tray to a machine (waterfalling) without conduit.
- Lower Cost: less time and materials are used.
- Neater Layouts: ideal for routing cable across complex floor plans.
Waterfalling cable to a machine is a great example of how TC-ER can simplify industrial setups. Configuring cable in this way, instead of running it through conduit, is safer and simplifies installation and maintenance.
CRUSH TEST: ENSURING TOUGHNESS
To earn an ER rating, the cable must pass rigorous crush and impact tests, ensuring it remains functional under harsh conditions.
One of the critical tests for ER tray cable is the crush test. For this test, the cable rests on a steel rod while a steel plate is slowly pressed down on top, compressing the cable against the rod. Afterward, the cable undergoes a conductivity test to determine if it still functions normally.
In industrial and commercial environments, cables can be subjected to mechanical stresses from a variety of sources. This test helps to ensure that the cable will still perform safely under extremely tough conditions.
IMPACT TEST: WITHSTANDING FORCE
ER tray cables also undergo an MC cable impact test. For this test, a current-carrying cable rests on a steel rod while a heavy steel block is repeatedly dropped along its length.
The cable fails the test if its insulation cracks, breaks, or if any fault occurs along its length. This test is particularly difficult to pass, as each drop of the block progressively weakens the cable insulation. Only cables that endure these repeated impacts while maintaining their integrity earn the ER rating.