This is as good of a place to stick this as any. In my opinion, if a cable overcurrent caused by a tripping surge suppressor can blow an injector, then something is not right in the injection circuitry, not the surge suppressor. There are a few cable faults one cannot protect against. This is not one of them.
As an poe injector manufacturer, I feel strongly that the responsibility for this type of failure rests solely on the manufacturer of the PoE injector. The overcurrent protection circuitry in the device should be designed well enough to handle most common faults, including this one. On Mar 20, 2017 6:50 PM, "Faisal Imtiaz" <[email protected]> wrote: >>>>Netonix. Toughswitch. Tycon. Anything that isn't AF and is passive PoE blows. That would be an in-correct statement or an in-correct assumption at best. Most passive switches have some-sort of over load protection built into them. The question of how fast they react would be a valid one. Matt you have to keep in mind that most equipment damage is not due to the 'short' but due to the current flowing in the wrong direction.. Regards Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: [email protected] ----- Original Message ----- > From: "Chuck McCown" <[email protected]> > To: "Matt Hoppes" <[email protected]> > Cc: [email protected] > Sent: Monday, March 20, 2017 7:58:53 PM > Subject: Re: [AFMUG] Question on APC Arresters > You never know which direction the surge is coming from, many times, perhaps > most times, it comes from the power lines and originates in the NOC gear. > And with a piece of CAT 5 going in and out of a surge protector, you never > know what the surge protector is connected to. A surge protector is > essentially a piece of CAT 5 or a CAT 5 coupler with a few extra components. > There really is no direction to them or a "tower side" to them. > > I could fuse all 8 wires. And have double surge suppressors. Or just put > surge on one side and label it "tower". > > How do you detect the direction of a nanosecond rise time pulse? You would > have to have an RF reflectometer on each of the 8 wires tied to some fast > logic. You would want sub microsecond switches that open the CAT5 and > logic to figure out where the pulse comes from and send it where? If it is > a powered wire on the POE where do you want that connected to during the > pulse? > > All surge suppressors I have ever seen do things essentially the same way I > do things. > > In any event, I will post this to the group. Perhaps there is a learning > opportunity for me here. Like to see if others have seen their POE blow > when shorted. I personally have not seen this before. > > -----Original Message----- > From: Matt Hoppes > Sent: Monday, March 20, 2017 5:46 PM > To: Chuck McCown > Subject: Re: Question on APC Arresters > > I'm not sure what the better option is. Not clamp on the power side, isolate > and clamp on the tower side only? > > So a surge comes in, break the connection between ground and tower and only > shunt tower side to ground. > > Honestly we were extremely surprised to find these did anything on the near > side of the unit. That came as a shock. > > Netonix. Toughswitch. Tycon. Anything that isn't AF and is passive PoE > blows. > >> On Mar 20, 2017, at 19:29, Chuck McCown <[email protected]> wrote: >> >> So, what would you have a suppressor do? Not clamp to ground? >> I have not run into POE switches that will blow if shorted. They are >> energy limited. >> What kind of switch? >> >> -----Original Message----- From: Matt Hoppes >> Sent: Monday, March 20, 2017 4:28 PM >> To: Chuck McCown >> Subject: Re: Question on APC Arresters >> >> So the problem we are running into is the suppressor fires and clamps >> which shorts the power supply on the switch, which kills the switch >> port. Now I'm out both a switch port and a suppressor.... I'm not sure >> what I've gained. >> >> River Valley Internet >> "We Never Forget You Have a Choice" >> 570-433-7070 x 700 >> >>> On 3/20/17 6:13 PM, Chuck McCown wrote: >>> Yes, they are clamping the wire. So think of most of our devices as 8 >>> individual surge suppressors. They will short the impulses to ground. >>> If (as is common) the impulses come in on all 8 wires at the same time, >>> all 8 wires are connected to ground and as a result they are also >>> connected to each other. >>> >>> -----Original Message----- From: Matt Hoppes >>> Sent: Monday, March 20, 2017 4:06 PM >>> To: [email protected] >>> Subject: Question on APC Arresters >>> >>> Hey Chuck... was discussing your Ethernet arresters last night. >>> >>> Is it normal operating mode for them, when they take a strike, to go >>> into a "short circuit" situation on both sides of the Ethernet port?
