Hi,
I would like to shield my board from noise coming from the outside world. I have opted to use an aluminium enclosure to house my PCB. I am hoping that by connecting the enclosure to the mains' Earth that the aluminium will conduct the radiated energy into the ground.
Just for background, in South Africa our mains plugs have 3 pins. We call it Live, Neutral and Earth (I noticed some other countries have different names for it). Live and Neutral comes directly from the mains transformer outside. In the distribution board they will run through an earth leakage circuit breaker and will be distributed through various other breakers. From each mains wall plug, the Earth wire will usually run through an Earth bus bar in the distribution board directly to the physical ground (usually a copper rod in the ground). Any current that flows from Live to Earth will trip the earth leakage breaker.
Now, back to the enclosure. The enclosure has slots on its side walls where my PCB can slide into. My idea is to have bare copper strips on both edges of the PCB which will make contact with the enclosure when the PCB is inserted in the enclosure's slots. Both copper strips will then each have a trace running to a central point on the PCB where I will connect the Earth wire. My theory is that this will provide a direct path to ground from the aluminium enclosure in order to catch and conduct any radiated energy into the ground and away from my circuits (obviously also any energy radiated from my circuit as well). It will also serve as a safety mechanism in case of the Live coupling to the enclosure.
It has occurred to me, though, that by connecting the Earth to both edges of the PCB I am effectively creating a loop through the enclosure metal. Is this a problem?
I would like to shield my board from noise coming from the outside world. I have opted to use an aluminium enclosure to house my PCB. I am hoping that by connecting the enclosure to the mains' Earth that the aluminium will conduct the radiated energy into the ground.
Just for background, in South Africa our mains plugs have 3 pins. We call it Live, Neutral and Earth (I noticed some other countries have different names for it). Live and Neutral comes directly from the mains transformer outside. In the distribution board they will run through an earth leakage circuit breaker and will be distributed through various other breakers. From each mains wall plug, the Earth wire will usually run through an Earth bus bar in the distribution board directly to the physical ground (usually a copper rod in the ground). Any current that flows from Live to Earth will trip the earth leakage breaker.
Now, back to the enclosure. The enclosure has slots on its side walls where my PCB can slide into. My idea is to have bare copper strips on both edges of the PCB which will make contact with the enclosure when the PCB is inserted in the enclosure's slots. Both copper strips will then each have a trace running to a central point on the PCB where I will connect the Earth wire. My theory is that this will provide a direct path to ground from the aluminium enclosure in order to catch and conduct any radiated energy into the ground and away from my circuits (obviously also any energy radiated from my circuit as well). It will also serve as a safety mechanism in case of the Live coupling to the enclosure.
It has occurred to me, though, that by connecting the Earth to both edges of the PCB I am effectively creating a loop through the enclosure metal. Is this a problem?