220V AC source on Universal PCB

Hi...I would want to ask if it is ok to connect a 220V AC source on my Universal PCB. I have a light bulb and a 5V SPDT relay which I would control through the microcontroller. I would want to connect the AC source and the bulb on the isolated part of the relay. I am planning to use terminal block for this and wire the connection on the universal PCB. Is it okay to do this? Thanks

Hi, what is a Universal PCB, if it is a proto board, with hundreds of holes and rows of conductors underneath, then NO.
They will not provide anywhere the insulation required to carry 220Vac.

If you mount the relay that is switching the 220Vac on a separate properly insulated piece of board and then run the wires that send current through the coil across to the low voltage control board then that should be okay.
But be careful with 220Vac..
Please post a copy of a circuit diagram showing us what you want to do.

Tom....... :slight_smile:

Hi. Thanks for the response.

Yes a universal PCB is like the one you have described consisting of grid of holes with very minimum spacing.

The schematic diagram is similar to that of the relay,
http://www.phidgets.com/docs/Mechanical_Relay_Primer.

The 5V input will be connected and controlled by the microcontroller, when the relay switches 'on' , i'm planning to turn on a load (bulb) that is rated 220V. I am planning to place all the components on one single PCB and what I have now is a universal PCB. Thanks

To isolate mains voltage on a PCB you need something like at least 1/4 inch clear board
with solder resist, or 1/2 inch without. Adding slots to further protect against flash-over is
wise. Consider an ant crawling over the board - you don't want it to be able to touch 220V
and low-voltage circuitry simulatenously or you'll short them together - a true killer ant.

This might be useful too:
http://qandasys.info/mains-to-low-voltage-seperation-between-fr4-pcb-layers/