Before we answer this question, we need to consider two aspects
(1) Is the camera going to be installed indoors or outdoors ?
(2) Is the site in a lightning prone area ?
Generally property developers install a lightning arrestor rod on top of buildings which is earthed. However this is no guarantee that lightning cannot strike any other area on that building, just that it reduces the probability. Therefore the answer to the above two follow-up questions assumes more significance.
Ans (1). An indoor camera DOES NOT need earthing or grounding. An Outdoor one does.
Ans (2). If the site is not in a lightning strike prone area, then any heavy weight earth protection will be very hard to justify, otherwise its should be implemented
Our site is India (Bengaluru) and that is not under a high risk zone. Outcomes incase of a strike can be one of the following:
(a) The strike NEITHER damages camera NOR SPREAD on the network
(b) The strike DAMAGES the camera but DOES NOT SPREAD on the network
(c) The strike DAMAGES the camera and SPREADS to other devices on the network potentially damaging them also, causing large scale damage
(c) is a no protection outcome while (a) is total protection. (b) is the balance point. If the site is a lightning prone zone, we have to invest in achieving (a) or (b) in worst case with (c) being unacceptable. If in a moderate probability zone (b) should be the target with (c) as being unacceptable. If in a safe zone , you maybe *tempted to ride your luck and just settle for (c) or no protection with (b) if you have spare cash, energy, time and possibly less appetite for gambling.
The mechanisms used to implementing earth are:
(1) The IP camera (or any outdoor device) housing is earthed - This maybe impractical to achieve
(2) The Outdoor IP camera cabling is Foiled (FTP) with drain wire [ensure its bonded to RJ45 shielded STP connectors only]
(3) Rack to rack ethernet connection is done using OFC uniformly instead of copper
(4) The switch supports lightning surge protection (ours don't) or an in-band PoE surge protection device (as shown below) is installed
(5) The switch chassis, rack and all metal parts in the rack is bonded to earth plate and that is earthed.
(6) The power supply to racks & switches is 3-pin (which has earthing) and it is ensured that ground is not open.
If all (1)-(6) of the above are implemented we will get outcome (a) or outcome (b). If (2) -(6) are implemented, likely outcome will be (b), which is what we want. If (4)-(6) or lesser are implemented the outcome will likely be (c) and if your luck holds up, (b). Anything less, you will probably ruin your equipment or endanger worker safety without lightning strikes even coming into the picture.
Our team has presently implemented (5), (4) & (2) and we want to implement (3) and till that time we are riding our luck (3 years now). Mainly not due to monetary or effort concerns, but due to in-band PoE surge protection device un-availability in local market [we expect this to change and then we will implement (3) also, but till then we are riding our luck].
- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee
(c) The strike DAMAGES the camera and SPREADS to other devices on the network potentially damaging them also, causing large scale damage
(c) is a no protection outcome while (a) is total protection. (b) is the balance point. If the site is a lightning prone zone, we have to invest in achieving (a) or (b) in worst case with (c) being unacceptable. If in a moderate probability zone (b) should be the target with (c) as being unacceptable. If in a safe zone , you maybe *tempted to ride your luck and just settle for (c) or no protection with (b) if you have spare cash, energy, time and possibly less appetite for gambling.
The mechanisms used to implementing earth are:
(1) The IP camera (or any outdoor device) housing is earthed - This maybe impractical to achieve
(2) The Outdoor IP camera cabling is Foiled (FTP) with drain wire [ensure its bonded to RJ45 shielded STP connectors only]
(3) Rack to rack ethernet connection is done using OFC uniformly instead of copper
(4) The switch supports lightning surge protection (ours don't) or an in-band PoE surge protection device (as shown below) is installed
(5) The switch chassis, rack and all metal parts in the rack is bonded to earth plate and that is earthed.
(6) The power supply to racks & switches is 3-pin (which has earthing) and it is ensured that ground is not open.
If all (1)-(6) of the above are implemented we will get outcome (a) or outcome (b). If (2) -(6) are implemented, likely outcome will be (b), which is what we want. If (4)-(6) or lesser are implemented the outcome will likely be (c) and if your luck holds up, (b). Anything less, you will probably ruin your equipment or endanger worker safety without lightning strikes even coming into the picture.
Our team has presently implemented (5), (4) & (2) and we want to implement (3) and till that time we are riding our luck (3 years now). Mainly not due to monetary or effort concerns, but due to in-band PoE surge protection device un-availability in local market [we expect this to change and then we will implement (3) also, but till then we are riding our luck].
- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee
No comments:
Post a Comment