Subscribing is a smart move!
You can subscribe to this board after you log in or create your free account.
Invite a Co-worker
Send a co-worker an invite to the portal.Just enter their email address and we'll connect them to register. After joining, they will belong to the same company.
Send Invite Cancel
Solved
Go to Solution
Link copied. Please paste this link to share this article on your social media post.
Accepted Solutions
Link copied. Please paste this link to share this article on your social media post.
The crackle is because the server power supply doesn't have good inrush current limiting and the plug is either being inserted too slowly or isn't making good contact. It is generating small sparks at the point of contact where the metal touches inside the plug and socket, and too much current is being drawn by the server power supply when there is not yet enough metal in contact to conduct that amount of electric current. If you shove the plugs in quickly then you minimise this problem and usually only get one small "click". In my own experience, crackles only happen when the plugs are not completely inserted, and sometimes they do need quite some force to get them to fully plug in. Sometimes people assume they are plugged in properly when in fact they just weren't pushing them in hard enough!
My understanding (I am not an electrical engineer) is that the inrush current is the same whether you hear a single crackle or not, but of course if you hear lots of crackles then you are probably causing repeated inrush events which increase the possibility that some current protection device will kick in. So it's not anything to panic about, but it is better to securely insert the plug as swiftly as you can to minimise the number of crackles you hear.
If you manage to cause too many crackles for too long a time, then it looks like an electrical overload (the opposite of a surge, where there is not enough power as opposed to too much power). I believe the ATS doesn't have any sort of current limiting in it, so the overload would just be passed up the chain to the next power distribution device (UPS, circuit breaker, etc.) If that decides there is too much power coming over the wire then it might trip, and the ATS will see there is no power coming from that source so it will switch to the secondary source. If the overload is still there then you might manage to trip your second source too! However this is extremely unlikely to happen from just inserting a power cable, unless there is an actual fault in the power supply.
Realistically the crackles are so brief that you are unlikely to cause anything to break because of them. Personally I prefer to minimise the number of crackles by inserting the plugs firmly and quickly, but for me this is more to ensure I don't provide bad quality power to the device I am plugging in. I'm sure if you intentionally made lots of crackles, the power supply in the device itself would fail long before the power cut out.
As a side note, I hate the relays APC use in the ATS devices, because the clicks they make when switching sound a lot like these crackles. It always makes me think the plugs are crackling like crazy when I plug in a source and I think something is going wrong when it turns out it's only the relays all clicking 
Link copied. Please paste this link to share this article on your social media post.
The crackle is because the server power supply doesn't have good inrush current limiting and the plug is either being inserted too slowly or isn't making good contact. It is generating small sparks at the point of contact where the metal touches inside the plug and socket, and too much current is being drawn by the server power supply when there is not yet enough metal in contact to conduct that amount of electric current. If you shove the plugs in quickly then you minimise this problem and usually only get one small "click". In my own experience, crackles only happen when the plugs are not completely inserted, and sometimes they do need quite some force to get them to fully plug in. Sometimes people assume they are plugged in properly when in fact they just weren't pushing them in hard enough!
My understanding (I am not an electrical engineer) is that the inrush current is the same whether you hear a single crackle or not, but of course if you hear lots of crackles then you are probably causing repeated inrush events which increase the possibility that some current protection device will kick in. So it's not anything to panic about, but it is better to securely insert the plug as swiftly as you can to minimise the number of crackles you hear.
If you manage to cause too many crackles for too long a time, then it looks like an electrical overload (the opposite of a surge, where there is not enough power as opposed to too much power). I believe the ATS doesn't have any sort of current limiting in it, so the overload would just be passed up the chain to the next power distribution device (UPS, circuit breaker, etc.) If that decides there is too much power coming over the wire then it might trip, and the ATS will see there is no power coming from that source so it will switch to the secondary source. If the overload is still there then you might manage to trip your second source too! However this is extremely unlikely to happen from just inserting a power cable, unless there is an actual fault in the power supply.
Realistically the crackles are so brief that you are unlikely to cause anything to break because of them. Personally I prefer to minimise the number of crackles by inserting the plugs firmly and quickly, but for me this is more to ensure I don't provide bad quality power to the device I am plugging in. I'm sure if you intentionally made lots of crackles, the power supply in the device itself would fail long before the power cut out.
As a side note, I hate the relays APC use in the ATS devices, because the clicks they make when switching sound a lot like these crackles. It always makes me think the plugs are crackling like crazy when I plug in a source and I think something is going wrong when it turns out it's only the relays all clicking
Create your free account or log in to subscribe to the board - and gain access to more than 10,000+ support articles along with insights from experts and peers.