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reduced cable

Hi guys just wanted to ask what you think of this. 


there is a bit of temporary kit which runs a 22KW motor. the FLC is 41 amps the cable supplying the motor is 10mm flex this then goes into a JB which someone has connected 6mm YY cable (4 core Lapp 130H) to extend the cable to a local isolater. the local isolator where the supply has been picked up from is a 100amp supply fed from a MCC approx 50 meters away. the method of starting is by soft start. 


I spoke to another Electrician who told me its fine as it is as the overload has been switched down. my thoughts were the overload protects the motor not the cable. I know the maximum capacity of the cable is 44amps so i can understand the overload should trip but is there an issue just relying on the overload. my suggestion was to down rate the fuses after the soft start to 40amps  i know its close but for a temporary measure, the motor runs at 32 amps normally.
Parents
  • So using an overload to protect the cable is fine. I understand circuit protection David sorry if I offended you in anyway i just wanted clarification if we could rely on protecting the cable through an overload relay as I’ve been told before they are purely just to protect the motor hence me asking if the addition of fuses are needed. I take it fuses would only be needed if the disconnection times cannot be met?
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  • So using an overload to protect the cable is fine. I understand circuit protection David sorry if I offended you in anyway i just wanted clarification if we could rely on protecting the cable through an overload relay as I’ve been told before they are purely just to protect the motor hence me asking if the addition of fuses are needed. I take it fuses would only be needed if the disconnection times cannot be met?
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