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I use screw terminals for a 230 VAC three-phase power supply, but it blasts in many PCBs, so I want to replace it. What would be a better solution?

ocrdu
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gaurav rajput
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  • You may want to show the damage also are you using creepage and clearance – Voltage Spike Mar 09 '23 at 07:15
  • @Voltage Spike I think no i am not using creepage and clearance – gaurav rajput Mar 09 '23 at 07:33
  • I see two problems in screw terminals: torque/force and creep. Please add to your question: in the *many blasts*, has there been an effective mechanical strain relief for the conductors/cables? (Dang. The mechanical effect isn't called *creepage* in English.) – greybeard Mar 09 '23 at 07:54
  • @greybeard kindly elaborate about screw terminals: torque and creep. and what does it stand for strain relief for conductors/cables?? – gaurav rajput Mar 09 '23 at 08:47
  • [With a strain relief component, the connection between a [potentially moving\] electrical line and its connection port is protected against mechanical stress.](https://en.m.wikipedia.org/wiki/Cable_management#Cable_strain_relief) Then, there is mechanical stress to terminal and board from the torque and axial force exerted when screwing the conductor tight (or loosen it) - with the terminal blocks shown, only the pins are there to counteract, and there are no mounting posts near to JP4. – greybeard Mar 09 '23 at 09:08
  • (P6 looks dislocated?!) – greybeard Mar 09 '23 at 10:03
  • _"I think no i am not using creepage and clearance"_ You are required by law and/or your insurance company in just about all countries to follow the rules for creepage and clearance. It's not just for compliance, but you will risk peoples lives by the fire hazard if you put a dangerous product on the market. – winny Mar 09 '23 at 10:59
  • How much current needs to pass through? Are the connector and PCB traces rated to handle that amount? What if there is a short on output, and the input connector acts as a fuse so the problem is not the input connector at all? – Justme Mar 09 '23 at 11:01

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Use terminal lugs and a screw block rated for me than 230V, terminal lugs have strain relief and good contact. Make sure there's adequate spacing between connectors. If there isn't spacing between conductors you will get arcing. If you are in a dirty environment with dust you have to have more spacing. The wire should also be able to carry current max current. There may also be issues with voltage spikes if you are switching 230 volt, it could be getting more than 230 volts if the spikes were getting up to say 400 volts you would have to have spacing on the terminal block for 400 volts otherwise you'll have arcing

Make sure you have enough space between the wires connectors and traces on the PCB.

Here are some tables that are defined by the IEC standards:

Creepage for printed boards / printed wiring material and IEC 60664

How far can mains voltage arc in air?

Voltage Spike
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