Cable Vibration When Starting a Motor

Yes, the magnetic force that comes from the current flowing in the cables will repel the adjacent cables' forces and the cables will bang around of not tied down or "triplexed", which means twisting them together prior to installation. It is a common mistake made by installers.

thank you very much

Use a "softstarter", and your cables (and as well the rest of your electric installation)will be at ease ...

While that will probably solve the immediate problem of cable rattling at startup, the fact that they are rattling means they are inadequately secured, which is a serious potential problem if there is a fault. The cable forces during a fault could cause separation from the terminals or physical damage to the insulation, which could make the entire situation exponentially worse. It's best to start out by properly securing the cables, then look into a soft starter because if you have that much energy being used to start the motor, that indicates that you may have a voltage drop problem. High starting current also could mean significant excess torque as well, which could be doing mechanical harm to other components.

Thanks JR, you completed my post !