Fusing 220 volt and grounding everything

2 posts in this topic

Hi there all, this is my first post.

I am DIY novice, building a control panel for my 5 axis CNC router. I need help with a few questions.

I have 5 power supplies that are 220 volt. Is it an acceptable practice to fuse just one leg of the power input. It seems when using fuses instead of a circuit breaker that trip both legs together, Using a single or double fuse would protect the unit. It seems the problem is if one or two fuses are used, just one fuse would blow and the other leg is left hot, is that a problem? Can I fuse just one leg?

Next question. Should I use the same grounding buss bar to ground everything. The main 220 volt power input, the computer, the DC power, the DC control circuit, the machine tool, the stepper motors, VFD, everything? Is there a potential for a ground loop or any other problem?

Thanks for your help


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5 power supplies that are 220 volt? Single phase 220 volt is a combination of 2- 110 volt wires. 3 phase 220 volt is the combination of 3- 110 volt lines used to power reversable electric motors. When a motor is turning in the wrong direction, swap 2 of the 110 volt wires and the motor will turn in the opposite direction.

Always disconnect all power before doing anything. After power is off check it with a meter. Check the meter. NOW CALL AN ELECTRICIAN.

Circuit breakers shut off power to all the lines the that go through them at the same time, protecting the whole cirçuit.

A Fuse only protects 1 part of the circuit. Sometimes only a small part of a cîrcuit is fused to protect a delicate component.

AC grounding is always grounded to the same ground and a bus bar is used to join many wire together.

DC is not ground. DC is 12 or 24 ,36... volt positive and 0 volts negative and needs to be connected to the negative post of the power supply. An AC to DC transformer should have power, neutral and grounding lugs on the AC side.

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