Contractors often have many tray cable options available when performing a job but knowing which type to use for what application can be confusing.
Despite being a large category, each tray cable has a general or specific use.
TC – This is the most common type of tray cable used in construction and electrical work. It’s a rugged and reliable workhorse that can be used inside and outside and adapts to nearly any use.
PLTC – Power-limited tray cables are cables only rated for 300V, as opposed to the 600V you see with a standard TC cable.
ITC – Instrumentation tray cable is a type of PLTC but is meant to be buried underground and can only have a drop length of 50 feet, regardless of the support structure. Like PLTC, this cable only has a 300V rating.
Despite all three types of cable having different uses, voltages, and applications, they share one thing in common. Each can be rated for exposed runs (-ER) and have the code printed on its jacketing.
Although ER often stands for “exposed run,” the abbreviation can also be referred to as “exposed reach” or “extended run.” Older tray cable installations could be printed with “Open Wiring,” which means the same thing. No matter what you call them, these cables can be used in the open air without needing to have a conduit, cable tray, or metal cladding protecting it.
Exposed run tray cable has been available since the 1990s, following updates made to the National Electrical Code (NEC) and Underwriters Laboratories requirements allowing for a new tray cable classification.
Tray cable typically needs armor outside the cable tray, but ER cabling doesn’t need the same protection. However, to be marked with the ER designation, the cables must meet strict crush and impact safety standards.
Cables with an ER rating don’t need raceways, conduits, or a cable tray. Instead, ER tray cable only needs to be supported every six feet using struts or another support structure.
Depending on the application, TC-ER cables could save you time and costs for a job.
In many cases, exposed run tray cables are a cost-effective approach to running electrical wire because they don’t require protection once leaving the tray. ER-rated tray cables remove the need for additional protection, which can ultimately save time and money for an entire project. Designers can even spec in type TC-ER wire from the start to keep the project budget-friendly.
Using traditional tray cable outside conduit, trays, or other raceways may not seem like a big deal, but it could run you afoul of the NEC.
All non-ER cabling has to be protected if it leaves the tray. Any situation where the cable isn’t protected with metal armor or other protection is non-compliant with NEC regulations and could lead to a hefty fine. It’s better to be safe and use a power cable with the correct cable markings.
So, what exactly do the regulations say? According to the NEC, exposed run cables must be installed between a cable tray and any electrical equipment. Most ER-rated cables don’t have any length guidelines (if they’re supported), though ITC-ER is limited to runs of 50 feet or less from the cable tray to its endpoint.
No matter what cable is used, if it’s run in the open, it needs to be supported using struts or other supports to avoid unintended damage.
Both may have “tray cable” in their name and maintain many of the same qualities, but TC-ER and direct bury are not entirely the same.
Direct bury tray cable has better crush and impact resistance than TC-ER because of where it is typically used. This cable is meant to be buried in a trench or used for other underground applications and will be under increased abrasion and crushing stress. It will also encounter moisture, chemicals, and other dangers that could impact its reliability and durability, along with needing to be sunlight resistant.
However, like TC-ER, direct bury cable can connect to electrical equipment without needing to be protected by conduit or other protective materials.
The type of cable you use can make a world of difference on the worksite. Understanding the differences between TC-ER and other tray cables could be what stands in the way between a safe, simple installation or a costly fine for not following the rules.
Not sure of what type of tray cable you need for the job? Kris-Tech has an entire team of experts who can help you find the industrial cabling you need for the job, quickly produce it with as much or as little custom work as you need and ship it out fast.
Contact us today to learn more about our products and how you can better we can help with your next installation.
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