This article contains my technical opinion and is for general information purposes only.
There is a lot of information on an electrical cable spec sheet. I’ll attempt to highlight a few of the important items on a typical cable spec sheet.
Standards – Cables are built to various Canadian and international standards. Ensure there is a CSA standard listed that fits your application. For instance, a CSA Tray Rating might be a requirement of your project for cables installed on cable trays or an NFPA 130 might be a fire safety standard requirement for a transit project.
Applications – The CSA approvals, combined with the CE Code requirements, determine if a cable can be used in your application. CE Code Table 19 lists conditions of use for various cables based upon CSA cable type.
Construction – Does the cable construction match your intended use? The spec may list optional features, but these features often are made-to-order, with a minimum order quantity and lead time. Examples of common optional features are jacket types, different shields, low smoke rating, colors, stranding, and water blocking systems.
Dimensional information – Most dimensional information is determined by the CSA standard the cable is built to. Items like insulation, armor, and jacket thicknesses are typically mandated by the standard within specified tolerances and will be common among cable brands. Cables have manufacturing tolerances that should be considered when selecting cable glands to ensure that your cable OD is not too close to gland fit range limits. I have seen ODs range by up to 10% between cables from the same manufacturer due to manufacturing tolerances adding up over each layer of the cable.
Conductor stranding type – Concentric, compressed, or compact stranding will change the conductor OD. Higher strand counts will affect overall cable OD and the lug size.
Bonding conductor size – Check to see if the cable comes with a bonding conductor as not all cable types do. CSA standards mandate the bonding conductor size. Custom bonding conductors can often be made but probably aren’t necessary as CE Code 10-614(7) states that bonding means that it's integral to a cable assembly and meets minimum code sizing requirements.
Ampacity numbers – For a Canadian project, the ampacity must come from either a CE Code ampacity table with appropriate correction factors, as calculated by an IEEE835 method, or an inspection deviation applied for. All methods must consider the application details such as conductor spacing, burial depth, and circuit temperature limit. The ampacity listed in the spec sheet is only valid if the assumptions it is based upon, your application, and a matching CE Code table all line-up. Spec sheets are a risky source of ampacity values as the application assumptions may not reflect your application. It is possible to undersize a cable by using a spec sheet ampacity number based upon a different application. As with anything, it is important to read the fine print.
Flame ratings – Look for a CSA FT4 rating as a CE Code requirement for exposed cables in non-combustible construction per CE Code 2-130. Cables without an FT4 rating need to be installed in conduit, masonry walls, concrete slabs, or be totally enclosed.
Temperature Ratings – While the maximum operating temperature is mandated by the CSA Standard, handling temperature ratings are left to the cable manufacturer. The rule of thumb is -40ᵒC marked cables can be handled down to -25ᵒC, and -25ᵒC marked cables handled down to -10ᵒC.
Spec sheets found via online searches are not 100% reliable. Often, they are outdated or made-to-order items with manufacturing lead times or minimum order quantities that don’t match your project requirements. Feel free to contact us before adding it to your specification or RFQ to confirm if the gauge size or cable type is an item that is typically stocked and available in the quantities or lengths you require. If you’re lucky enough to have a large project with plenty of time to order cables, you can consider made-to-order constructions that best fit your specific application.
For more information on cable installation and handling, read our articles on cable pulling calculations, how to handle low temperature cables, and minimum cable bend radius for power & control.
