Dedicated home theater line & surge protection - AVS Forum
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post #1 of 13 Old 01-18-2011, 02:34 PM - Thread Starter
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Let me start by saying that I have read through the massive 60+ page threads of people arguing about surge protection located in various subforums. I am aware that there is very little some people can agree on in this area.

Hopefully this is an appropriate forum for my question.

I have run a dedicated 20amp line from the breaker for my new home theater room. I have also installed a whole house surge protector at the service panel. My research and intuition leads me to believe I should "layer" the surge protection, so in addition to the whole house unit I am going to add protection to my 20 amp circuit.

I am looking to install a Surgex SX20ne http://www.surgex.com/products/sx20ne.html on my 20amp line. The installation instructions do not provide a clear answer, so my question is this: should I locate the protector close to the service panel, or close to the equipment?

If placed at the service panel, the protector would be roughly 70 feet of 12/2 romex away from the equipment racks.

This NEMA article http://www.nemasurge.com/ins/i-installer.html seems to generally indicate that protection should be added close to the service panel.

However, other sources all agree that the second layer of protection should be located as close to the equipment as possible. Since I already have protection at the panel, should I install my second layer of protection close to the equipment? This seems intuitively correct to me, because less wire length = less chance of interference with other lines, ect.

Any insight would be greatly appreciated.
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post #2 of 13 Old 01-18-2011, 04:44 PM
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I think I would go with what the folks at SurgeX recommend.
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post #3 of 13 Old 01-18-2011, 05:12 PM - Thread Starter
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Quote:
Originally Posted by Colm View Post

I think I would go with what the folks at SurgeX recommend.

Unfortunately they do not make any recommendations.
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post #4 of 13 Old 01-18-2011, 05:29 PM
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Well, if your gear is on a dedicated circuit, I can only think of two possible issues. If a nearby lightning strike induces a surge directly on the branch circuit wiring, having the device close to the gear might be advantageous. But you will still be left open to damage from surges induced on any other wiring to the AV gear like cable TV, etc. OTOH I think you will have more to worry about than your AV gear if that happens.

The second issue is the magnitude of the surge that the device might be exposed to. The UL testing requirements for point-of-use devices, those located at least 30 feet from wiring from the panel, are different than the requirements for devices located closer to the panel. Essentially, the closer to the panel, the larger the exposure. The impedance of 30' or more of branch wiring limits the surge that can be seen by the device. I would hope that SurgeX devices intended to protect an entire circuit are designed with that difference in mind, but I don't know. Optimally, we would have UL 1449 3rd. Ed. test results to go by. But they don't seem to be available yet.
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post #5 of 13 Old 01-18-2011, 11:20 PM - Thread Starter
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Quote:
Originally Posted by Colm View Post

Well, if your gear is on a dedicated circuit, I can only think of two possible issues. If a nearby lightning strike induces a surge directly on the branch circuit wiring, having the device close to the gear might be advantageous. But you will still be left open to damage from surges induced on any other wiring to the AV gear like cable TV, etc. OTOH I think you will have more to worry about than your AV gear if that happens.

The second issue is the magnitude of the surge that the device might be exposed to. The UL testing requirements for point-of-use devices, those located at least 30 feet from wiring from the panel, are different than the requirements for devices located closer to the panel. Essentially, the closer to the panel, the larger the exposure. The impedance of 30' or more of branch wiring limits the surge that can be seen by the device. I would hope that SurgeX devices intended to protect an entire circuit are designed with that difference in mind, but I don't know. Optimally, we would have UL 1449 3rd. Ed. test results to go by. But they don't seem to be available yet.

Thanks for the reply. According to SurgeX, the unit meets the UL requirements for the service entrance:

"SX20 NE units are 20-amp load-capable, 10" x 8" x 4" NEMA enclosures and meet code for use at the service entrance, sub-panels and in ceiling plenums. "

I was kind of hoping your point would answer my question, but I guess not.
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post #6 of 13 Old 01-19-2011, 12:12 AM
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I am not an expert in the area but having talked to an electrical engineer it was suggested to me that if you have a good quality surge protector at your panel that anything else is a waste of money. I am currently building a new house and will only install the panel protector due to this advice.
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post #7 of 13 Old 01-19-2011, 01:00 AM
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Quote:
Originally Posted by MasterChief View Post

"SX20 NE units are 20-amp load-capable, 10" x 8" x 4" NEMA enclosures and meet code for use at the service entrance, sub-panels and in ceiling plenums. "

Never doubted that it met code to install. Code is one thing. UL 1449 3rd Ed. test results for a Type 1 or Type 2 device are something else.

I doubt that it makes much difference where you install the device. But I think you should get some advice from an engineer at SurgeX. They are the experts on the device.
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post #8 of 13 Old 03-28-2012, 09:28 AM
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Anytime you are getting surge damage the first point to address is the grounding. If the electrical service ground is not below 10-Ohms then anything you do after that to protect will be minimal at best. All grounds should be referencing the same single point reference or you will experience noise, poor picture quality and equipment damage. Once you verify a single point ground reference of low impedance then you can move to the second step... proper surge protection. Most residential surge suppression is garbage. Plug in devices do very little or nothing at all. Remember that the surge suppression installed on electrical distribution panels should have an active transient filter to provide clean power. Most panel-mount surge suppressors are MOV based and therefore will only turn on and address the surge once it has elevated well above the electrical sine wave. That's fine for protecting motors but unfortunately by the time the surge energy has elevated that high your electronics are toast or degraded dramatically at best. The suge experience through the HDMI cable is still being generrated at the AC level and has sifted its way through the amp tot he HDMI port to seek ground. The surge "sees" the ground reference from the TV as separate from the ground reference from the amp. Even though the grounds originate at the same main electrical service, note that the ground conductor from the breaker panel to the receptacle is probably only 14 AWG wire and therefore the impedance (resistance) from that long wire run will change the ground reading between the two pieces of equipment. I recommend Total Protection Solutions surge suppression because they have a proprietary filter that provide computer grade power 24/7 and the best warranty in the business. They focus on large commercial and industrial applications but they have a residential division as well.
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post #9 of 13 Old 03-28-2012, 10:45 AM
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How about adding a UPS, it'll give you additional surge protection (if you decide you need it) plus protect your PJ by giving it time to shutdown properly in case of a power failure.
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post #10 of 13 Old 03-28-2012, 12:03 PM
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I had installed a whole-house protector (Square-D brand) at my old home and used no other protection. (I do have my PCs on UPSs). Lighting struck in the backyard between our house and our neighbor's about 6 years ago...nothing in my home was affected. My neighbor had to replace everything that was plugged in.

Needless to say, I'll be installing one of those at my new home as well.

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post #11 of 13 Old 03-30-2012, 09:07 PM
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Quote:
Originally Posted by trebor58 View Post

Anytime you are getting surge damage the first point to address is the grounding. If the electrical service ground is not below 10-Ohms then anything you do after that to protect will be minimal at best. .

How do you measure this?
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post #12 of 13 Old 03-31-2012, 04:31 AM
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Quote:
Originally Posted by hoffmand34 View Post

How do you measure this?

With a ground resistance tester. Not many electricians have them in my area, as they cost ~$1000 and that's basically all the tester can do.

Tim
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post #13 of 13 Old 03-31-2012, 09:56 AM
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Quote:
Originally Posted by chomperoni View Post

I am not an expert in the area but having talked to an electrical engineer it was suggested to me that if you have a good quality surge protector at your panel that anything else is a waste of money. I am currently building a new house and will only install the panel protector due to this advice.

Good advise...a whole house device should be the first thing installed...but a lot of electrical disturbances originate from within the home...and a point of use device can protect from those too.

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