Earth Grounding for AC and DC Voltage: Safety Precautions and Considerations

[AbbasC]

Can we Earth ground AC and DC voltage?
would this effect the components on the system?

 

[AbbasC]

I mean can we Earth Ground it together?

 

[Studiot]

Perhaps if you were to explain what you are trying to do ?

 

[AbbasC]

The system that I'm installing has power supply (input AC) and the output voltage is DC. The output voltage is connected to other DC components I also have 2 computers. I want to Earth GND the system could I connect the Gnd to one point. the system is inside a car so i was wondering if I can GND all the component to the Chassis of the car.
Thank you for your reply

 

[Studiot]

Now I'm even more confused.



You have an AC power supply to equipment in a vehicle?

Where does the AC come from?

 

[AbbasC]

lol its hard to explain the system :)

The AC comes from an inverter (input voltage is from the car battery) .The inverter is connected to UPS which is connected to the power supply and computer. And the power supply gives DC voltage (24V and 12 V) to the other parts of the system.

 

[Studiot]

Inverters such as this are isolated between input and output. Connecting one side of each to a common point will destroy that isolation.

The input is already connected via the battery supply to the vehicle chassis earth.
The AC is best left floating and well insulated. If you require real gold plated it could be encased in an metal armoured cable or conduit which is earthed vehicle chassis. This would on act electrically in a fault condition as a safety return.

Within the equipment supply the AC is converted back to DC which is also isolated from the incoming AC.

So this DC is then used to power the equipment.

You should not use the vehicle chassis to carry the power return (negative?) currents. There should be both positive and negative supply lines.

Is the powered equipment connected to the vehicle electrical system or just for use whithin the vehicle?

 

[AbbasC]

There is 2 lines for the DC voltage.But what is going on exactly is that some DC equipments have there chassis grounded to the main Earth GND.
The power system isn't connected to the vehicle electrical system.
So eventually all the components of the system is grounded to the Earth Ground.One of the DC component broke down so I was wondering if this happened because of the grounding.since all the system is mechanically grounded together.

 

[Studiot]

It is a basic safety principle that you should not use safety components or connections to carry working current. So the chassis of the various pieces of equipment should only be connected together for safety purposes. I have already noted this.

If you use these chassis connections ( as vehicle manufacturers once used to do) as one of the power leads it can lead to unreliability or even failure of something. That is why manufacturers have moved towards providing separate positive and negative power leads. Aircraft manufacturers have long lead the way forward in this respect.

Without full details of the system it would be unwise to comment further.