This blog post contains my technical opinion and is for general information purposes only. Your local Authority Having Jurisdiction may have a different interpretation, so please confirm your AHJ’s position prior to using this information. Please refer to the latest CE Code version for guidance on cable usage.
Type TC tray cables are unarmored cables rated for use in cable trays. While Teck90 has long been the standard Canadian industrial cable, tray cables are more typically used in equivalent US projects. Since the mid-1990’s, the Canadian petrochemical industry has been successfully using tray cables.
Type TC tray cables consist of power/control conductors or pairs/triads under a single overall jacket. The conductors are commonly insulated with XLPE and are housed in an overall PVC jacket. Tray cables are constructed per applicable CSA cable standards with the additional requirements of CSA C22.2 #230 for specific tray cable testing and marking. The #230 standard covers both single conductor and multi conductor cables for use in wet or dry cable tray applications, with FT4 and sunlight resistance ratings. Most CSA tray cables on the market are -40oC marked like Teck90, while most UL tray cables can only meet the -25oC tests.
CE Code Table 19 lists the various Type TC tray cable conditions of use. You will find that tray cables can be used in almost all the same applications as Teck90 cables, including cable trays, direct burial, duct banks, troughs, continuous rigid supports, and concrete encasement. One exception is that tray cable will typically not be HL marked for use in Class 1 Div 1 locations but per 18-152(1)(C) and Table 19, they can be installed in cable trays in Class 1 Div 2 and Class 2 Div 2 hazardous locations. You will still need an HL marked on the jacket armored cable for your Class 1 Div 1 locations.
CSA Cable Standards for Type TC Tray Cables:
|CSA C22.2 #38||Thermoset Cables|
|CSA C22.2 #75||Thermoplastic Cables|
|CSA C22.2 #239||Control & Instrumentation|
|CSA C22.2 #230||Tray Cables|
The pros of tray cables include cost savings, especially for smaller conductor/pair counts and gauge sizes up to about 2 AWG. The smaller OD makes the cable lighter and allows for a tighter bend radius and less tray fill. The lack of inner jacket and armor allows you to use less expensive connectors and less connector installation labor. The main cons were around unclear code rules on acceptable installations when they come off the cable trays. However, protection by location code deviations and changes in recent code update cycles have removed most of these concerns. In a future newsletter, I’ll expand on protection by location and TC-ER code rules. In the meantime, you can review CE Code rule 12-2202 for installation requirements of tray cables.
A common Canadian petrochemical corporate cable spec is to use tray cables for instrumentation, control, and power circuits up to 2 AWG circuits. Distribution inventories have responded to this demand by stocking these products in commonly used gauge sizes, reducing lead time and minimum order quantity challenges.
Caution: CE Code Rules
CE Code rule 12-2202 (2)(c) limits single conductors tray cables to 1/0 and larger
In Canada, we are conditioned to believe that only heavy-duty Teck90 cables can stand up to the severe requirements of our Industrial projects. Tray cables are much more robust than you might think. An engineer evaluating the use of tray cables in his large Alberta refinery project famously tested the durability of these cables by leaving them outside his home over the winter. When it would get especially cold, he would “test” them with a hammer. The cables passed his homemade testing set up with flying colors and they were specified for use in instrumentation, control, and power circuits.
Tray cables have become easier to use with each CE Code update and can provide many advantages over Teck90 cables. With cost savings especially critical to push projects ahead in today’s environment, now might be a good time to evaluate tray cables as a possible solution. It is always possible to overbuild products, but the incremental benefits may not be justified by economics.