I am looking at some PCBA's with ethernet RJ45 connector regarding surge test susceptibility. Common legal requirement are 1.5kV isolation.
The first issue that I see is PCBA's with RJ45 connector metal housing grounded to logical 0V (ground plane). Like Raspberry PI for example. Look at the bottom side of it. A surge impulse of 1,5kV on the shield of a STP cable will see no isolatation at all. It has direct galvanic connection to 0V. Surge impulse has lot of energy and as I see it will destroy the electronics at the first impulse.
The second issue I see is PCBA's with good isolation (4mm) between RJ45 connector and logical 0V, but with just 0.5mm isolation between the ethernet status LEDs (routed directed from the PHY) and RJ45 housing. This makes the 4mm barrier to have a weak spot of just 0.5mm, which definately should destroy the electronics too when STP ethernet cables are used.
What are your thoughts and experiences?
The first issue that I see is PCBA's with RJ45 connector metal housing grounded to logical 0V (ground plane). Like Raspberry PI for example. Look at the bottom side of it. A surge impulse of 1,5kV on the shield of a STP cable will see no isolatation at all. It has direct galvanic connection to 0V. Surge impulse has lot of energy and as I see it will destroy the electronics at the first impulse.
The second issue I see is PCBA's with good isolation (4mm) between RJ45 connector and logical 0V, but with just 0.5mm isolation between the ethernet status LEDs (routed directed from the PHY) and RJ45 housing. This makes the 4mm barrier to have a weak spot of just 0.5mm, which definately should destroy the electronics too when STP ethernet cables are used.
What are your thoughts and experiences?