Are you an industrial plant engineer about to begin a...
What is the difference between a cable tray and a cable ladder?Cable ladders comprise multiple rungs used to support heavy cabling that has significant spans between each support. On the other hand, cable trays are a preferred option for less industrial-grade projects, tubing, and supporting instrumentation. Cable ladders are designed with parallel rails that are linked with rungs and set out at equal intervals. If you need to use cable ties with cable ladders, you’ll have no problems, and your wires will also benefit as there is hardly any moisture or dust accumulation. Cable trays don’t have the rungs that cable ladders have. They are one sheet of metal with slots that are arranged in patterns. You can also use cable ties with cable trays, and this type of cable support is ideal for electromagnetic interference mitigation.
What are some different types of cable ladders?Some of the main types of cable ladders include Nema 1, Nema 20b, Nema 16a, and Nema 2. Here’s more information on each of these cable ladder types.
What is the Nema 1 cable ladder?The Nema 1 cable ladder is a cable ladder that’s ideal for supporting cable lengths that span 1.5 meters and weigh approximately 248kg per meter. You can also use a Nema 1 cable ladder for supporting cable lengths that span three meters and weigh about 112kg per meter. Depending on your requirements, you can opt for the three-meter-long Nema 1 ladder or the six-meter-long option. The Nema 1 cable ladder has a cabling loading depth of 43 millimeters.
What is the Nema 20b cable ladder?The Nema 20b cable ladder is ideal for supporting cable lengths that span six meters and weigh 112kg per meter. Keep in mind that the cabling loading depth of the Nema 20b cable ladder is 109 millimeters.
What is the Nema 16a cable ladder?The Nema 16a cable ladder is ideal for supporting cable lengths that span six meters and weigh 79kg per meter. It’s also crucial to keep in mind that the cabling loading depth of the Nema 16a cable ladder is 72 millimeters.
What is the Nema 2 cable ladder?The Nema 2 cable ladder is perfect for supporting cable lengths spanning four meters and weighing 113kg per meter. Keep in mind that the cabling loading depth of the Nema 2 cable ladder is 75 millimeters.
How do you choose cable size from the current rating?You can effortlessly calculate and choose the correct cable sizing by using the following calculation:
- Cable sizing = voltage through cable / target current
How do I choose the suitable cable?When selecting a cable, you have three factors to think about: the cable’s maximum current capacity, voltage regulation, and the short circuit rating.
1. Note the maximum current that the cable can withstandWhen noting the maximum current that the cable can withstand, remember that larger cable cross-sections will result in less loss in current resistance. For this reason, you may want to select cables that have bigger cross-sections.
2. Work out the voltage dropSee the formula below to determine the voltage drop, which is essential because as the current flows, it’s essential to factor in the change in voltage:
- Voltage drop = voltage drop per meter for each ampere x circuit conductor length x current / 1000
3. Determine the conditions for short-circuitingSince high currents can damage cables, it’s essential to consider the conditions for short-circuiting to determine the minimum cable size. Use the following formula to determine the minimum cable size:
- Minimum cable size = √(short circuit current2 x time for the short circuit) / short circuit temperature