Whether you’re using a low-voltage cable for your audio equipment or for a power tool, it’s wise to understand resistance and reactance, the two resistances that make up impedance. Resistance and reactance resist the flow of electricity in the low-voltage cable and will affect your equipment and its performance.
Getting the best quality sound, and taking the best care of your equipment, may depend on choosing a low-voltage cable with the right levels of resistance and reactance. Here’s what you need to know.
The Basics of Resistance and ReactanceResistance is like a large rock in a river. It resists the flow of electrical current in your cable. Reactance is different in that it is in opposition to the flow of a varying current. Resistance and reactance matter because your sound equipment will have a rating for what impedance level they work best at. Too low, and you can stress your equipment unless it was designed to handle the additional current. Too high, and your equipment won’t get what it needs to work. Most amplified receivers need 6 to 8 Ohms of impedance, but it will depend on your specific equipment.
Which Wire Has the Most Resistance?That depends. The resistance in a wire depends on many factors, including the length of the wire, the temperature and the material. It is best to get the exact resistance range that you need. The range will not be listed as resistance. Instead, it will be listed as overall impedance, which is measured in ohms. We have a range of wires that may be suitable for you available for rent. They range in sizes from #6 – 500MCM, voltages from 120V to 29kV and lengths from 5’ft to 100’ft. We can help you find a suitable cable for your purposes. To learn more on how you can protect your sound equipment and the importance of resistance and reactance in low voltage cables, contact our experts at VCM Solutions today.
How to Test Low-Voltage WiringHaving some trouble with your low-voltage wiring? Here is how to test it:
- Compare your drawings to your cable data. Is everything as it should be?
- Check cables for physical damage. Is the cable jacket intact, and are the connection points as they should be on your diagram?
- Use a low-resistance ohmmeter and compare the values of similarly bolted connects. If any deviate from the lowest value by more than 50%, they are worth investigating.
- Test the insulation resistance on each conductor as compared to its adjacent conductors and those on the ground. Test for one minute and follow your manufacturer’s instructions.
- What about cable connection and phasing? You can perform continuity tests to find incorrect phasing.
- Using that same low-resistance ohmmeter, verify that parallel conductors have uniform resistance. If they don’t, then you should investigate them.