Surge Protector Joule Rating

[Anonymous user]

I've got a model PF11VNT3 surge protector that I bought several years ago. There are 2 Joule ratings for the amount of energy they can withstand. According to APC's website and the box it came in, it has a "surge energy rating" of 2030 Joules. It also states that it has an "eP Joule rating" of 3400 Joules. Can someone explain the difference between these 2 values? Also, which one should I normally refer to in choosing a surge protector? And how should I use these ratings to compare to other manufacturers' surge protestors, such as Belkin? I have a simple home PC network consisting of 2 PC's fed by a coaxial cable system and modem and router, and I intend on using this surge protector to protect it. Thanks.

[Anonymous user]

Hi triumphshowdog, are there any other model number on the unit you are referring too? I am trying to figure out exactly what product we are dealing with. When it comes to surge devices typically the most important number or measurement is the let through voltage. The let through voltage is the measurement of how much voltage gets passed on to the connected load. While the joule rating can be helpful, it does not tell anything about the voltage being passed to your load (which is what we are effectively trying to reduce/eliminate with a surge product). Hope this helps.

[Anonymous user · Accepted solution]

Thanks for getting back so quickly. I bought the surge protector several years ago, and it looks like it's been replaced by a newer model by looking at APC's website. The literature I have on it again has a model # of PF11VNT3. It's described as a "SurgeArrest Performance" surge protector. It has EMI/RFI Noise rejection of 70 dB, Peak current normal mode= 20 kA, Peak current common mode = 60 kA, data line protection for RJ-11 modem/fax/dsl, RJ-45 10/100 Base T-Ethernet potection coaxial video/cable protection. It also has a let through voltage rating of < 40V. The serial # is 4Z0333P42060.
Up until now, I've had a Belkin "Isolator" surge protector on my small home pc network. This just protects my phone landline and the electrical connections to my equipment. I however have a cable/coaxial moden feeding me the internet, so I see a hole in my protection as to lightning getting in via my cable system. I've recently had a problem with my router losing connection frequently in conjunction to a recent bad lightning storm in my area. So I thought maybe lightning got in through the cable and damaged the router.
One problem I've heard with surge protectors on cable systems is that they limit the internet signal and that internet connection has been compromised or lost. As an add-on to my original question, I was wondering if anyone had any experience with this happening.
I didn't know if this existing APC surge protector I have would be better suited for my pc network, or if the existing Belkin I have on it now would be adequate protection.
I've been able to get my router working again, but I thought that this does bring to light a hole in my lightning protection.
Any comments on any of the above would be certainly welcome. Thanks again.